STL rework

- fixed lots of bugs
- overlay libraries work correctly and reliably
- the STL is an overlay library
- examples updated

Cargo.lock

@@ -24,6 +24,15 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "aho-corasick"
+version = "0.7.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc936419f96fa211c1b9166887b38e5e40b19958e5b895be7c1f93adec7071ac"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "anstream"
 version = "0.3.2"
@@ -85,6 +94,25 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "block-buffer"
+version = "0.10.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3078c7629b62d3f0439517fa394996acacc5cbc91c5a20d8c658e77abd503a71"
+dependencies = [
+ "generic-array",
+]
+
+[[package]]
+name = "bstr"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a246e68bb43f6cd9db24bea052a53e40405417c5fb372e3d1a8a7f770a564ef5"
+dependencies = [
+ "memchr",
+ "serde",
+]
+
 [[package]]
 name = "cc"
 version = "1.0.79"
@@ -109,9 +137,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "4.2.7"
+version = "4.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "34d21f9bf1b425d2968943631ec91202fe5e837264063503708b83013f8fc938"
+checksum = "80672091db20273a15cf9fdd4e47ed43b5091ec9841bf4c6145c9dfbbcae09ed"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -120,9 +148,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.2.7"
+version = "4.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "914c8c79fb560f238ef6429439a30023c862f7a28e688c58f7203f12b29970bd"
+checksum = "c1458a1df40e1e2afebb7ab60ce55c1fa8f431146205aa5f4887e0b111c27636"
 dependencies = [
  "anstream",
  "anstyle",
@@ -133,9 +161,9 @@ dependencies = [
 
 [[package]]
 name = "clap_derive"
-version = "4.2.0"
+version = "4.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3f9644cd56d6b87dbe899ef8b053e331c0637664e9e21a33dfcdc36093f5c5c4"
+checksum = "b8cd2b2a819ad6eec39e8f1d6b53001af1e5469f8c177579cdaeb313115b825f"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -145,9 +173,9 @@ dependencies = [
 
 [[package]]
 name = "clap_lex"
-version = "0.4.1"
+version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8a2dd5a6fe8c6e3502f568a6353e5273bbb15193ad9a89e457b9970798efbea1"
+checksum = "2da6da31387c7e4ef160ffab6d5e7f00c42626fe39aea70a7b0f1773f7dd6c1b"
 
 [[package]]
 name = "colorchoice"
@@ -155,6 +183,35 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "acbf1af155f9b9ef647e42cdc158db4b64a1b61f743629225fde6f3e0be2a7c7"
 
+[[package]]
+name = "cpufeatures"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3e4c1eaa2012c47becbbad2ab175484c2a84d1185b566fb2cc5b8707343dfe58"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "crypto-common"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bfb12502f3fc46cca1bb51ac28df9d618d813cdc3d2f25b9fe775a34af26bb3"
+dependencies = [
+ "generic-array",
+ "typenum",
+]
+
+[[package]]
+name = "digest"
+version = "0.10.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ed9a281f7bc9b7576e61468ba615a66a5c8cfdff42420a70aa82701a3b1e292"
+dependencies = [
+ "block-buffer",
+ "crypto-common",
+]
+
 [[package]]
 name = "dyn-clone"
 version = "1.0.11"
@@ -188,6 +245,22 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "fnv"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
+
+[[package]]
+name = "generic-array"
+version = "0.14.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85649ca51fd72272d7821adaf274ad91c288277713d9c18820d8499a7ff69e9a"
+dependencies = [
+ "typenum",
+ "version_check",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.8"
@@ -199,6 +272,19 @@ dependencies = [
  "wasi",
 ]
 
+[[package]]
+name = "globset"
+version = "0.4.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "029d74589adefde59de1a0c4f4732695c32805624aec7b68d91503d4dba79afc"
+dependencies = [
+ "aho-corasick",
+ "bstr",
+ "fnv",
+ "log",
+ "regex",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.12.3"
@@ -273,6 +359,21 @@ version = "0.3.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ece97ea872ece730aed82664c424eb4c8291e1ff2480247ccf7409044bc6479f"
 
+[[package]]
+name = "log"
+version = "0.4.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abb12e687cfb44aa40f41fc3978ef76448f9b6038cad6aef4259d3c095a2382e"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "memchr"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
+
 [[package]]
 name = "num-traits"
 version = "0.2.15"
@@ -299,15 +400,16 @@ dependencies = [
  "itertools",
  "ordered-float",
  "paste",
+ "rust-embed",
  "thiserror",
  "trait-set",
 ]
 
 [[package]]
 name = "ordered-float"
-version = "3.6.0"
+version = "3.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13a384337e997e6860ffbaa83708b2ef329fd8c54cb67a5f64d421e0f943254f"
+checksum = "2fc2dbde8f8a79f2102cc474ceb0ad68e3b80b85289ea62389b60e66777e4213"
 dependencies = [
  "num-traits",
 ]
@@ -345,6 +447,58 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "regex"
+version = "1.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b1f693b24f6ac912f4893ef08244d70b6067480d2f1a46e950c9691e6749d1d"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.6.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f162c6dd7b008981e4d40210aca20b4bd0f9b60ca9271061b07f78537722f2e1"
+
+[[package]]
+name = "rust-embed"
+version = "6.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b68543d5527e158213414a92832d2aab11a84d2571a5eb021ebe22c43aab066"
+dependencies = [
+ "rust-embed-impl",
+ "rust-embed-utils",
+ "walkdir",
+]
+
+[[package]]
+name = "rust-embed-impl"
+version = "6.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4d4e0f0ced47ded9a68374ac145edd65a6c1fa13a96447b873660b2a568a0fd7"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "rust-embed-utils",
+ "syn 1.0.109",
+ "walkdir",
+]
+
+[[package]]
+name = "rust-embed-utils"
+version = "7.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "512b0ab6853f7e14e3c8754acb43d6f748bb9ced66aa5915a6553ac8213f7731"
+dependencies = [
+ "globset",
+ "sha2",
+ "walkdir",
+]
+
 [[package]]
 name = "rustix"
 version = "0.37.19"
@@ -359,6 +513,32 @@ dependencies = [
  "windows-sys",
 ]
 
+[[package]]
+name = "same-file"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
+dependencies = [
+ "winapi-util",
+]
+
+[[package]]
+name = "serde"
+version = "1.0.160"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb2f3770c8bce3bcda7e149193a069a0f4365bda1fa5cd88e03bca26afc1216c"
+
+[[package]]
+name = "sha2"
+version = "0.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "82e6b795fe2e3b1e845bafcb27aa35405c4d47cdfc92af5fc8d3002f76cebdc0"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "digest",
+]
+
 [[package]]
 name = "stacker"
 version = "0.1.15"
@@ -431,6 +611,12 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "typenum"
+version = "1.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "497961ef93d974e23eb6f433eb5fe1b7930b659f06d12dec6fc44a8f554c0bba"
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.8"
@@ -449,6 +635,16 @@ version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
 
+[[package]]
+name = "walkdir"
+version = "2.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "36df944cda56c7d8d8b7496af378e6b16de9284591917d307c9b4d313c44e698"
+dependencies = [
+ "same-file",
+ "winapi-util",
+]
+
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"
@@ -471,6 +667,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"

Cargo.toml

@@ -23,11 +23,12 @@ doc = false
 
 [dependencies]
 thiserror = "1.0"
-chumsky = "0.9.2"
+chumsky = "0.9"
-hashbrown = "0.13.2"
+hashbrown = "0.13"
-ordered-float = "3.0"
+ordered-float = "3.7"
 itertools = "0.10"
-dyn-clone = "1.0.11"
+dyn-clone = "1.0"
-clap = { version = "4.2.4", features = ["derive"] }
+clap = { version = "4.3", features = ["derive"] }
-trait-set = "0.3.0"
+trait-set = "0.3"
-paste = "1.0.12"
+paste = "1.0"
+rust-embed = { version = "6.6", features = ["include-exclude"] }

examples/calculator/main.orc

@@ -1,16 +1,15 @@
-import std::(parse_float, to_string)
+import std::(proc::*, to_float, to_string, io::(readline, print))
-import std::(readline, print)
 
 export main := do{
   cps print "left operand: ";
   cps data = readline;
-  let a = parse_float data;
+  let a = to_float data;
   cps print "operator: ";
   cps op = readline;
   cps print ("you selected \"" ++ op ++ "\"\n");
   cps print "right operand: ";
   cps data = readline;
-  let b = parse_float data;
+  let b = to_float data;
   let result = (
     if op == "+" then a + b
     else if op == "-" then a - b

examples/hello-world/main.orc

@@ -1,3 +1,3 @@
-import std::print
+import std::io::print
 
 main := print "Hello, world!\n" "goodbye"

examples/list-processing/list.orc

@@ -1,41 +0,0 @@
-import option
-import super::fn::*
-
-pair := \a.\b. \f. f a b
-
--- Constructors
-
-export cons := \hd.\tl. option::some (pair hd tl)
-export end := option::none
-
-export pop := \list.\default.\f.list default \cons.cons f
-
--- Operators
-
-export reduce := \list.\acc.\f. (
-  loop r on (list acc) with
-    pop list acc \head.\tail. r tail (f acc head)
-)
-
-export map := \list.\f. (
-  loop r on (list) with
-    pop list end \head.\tail. cons (f head) (r tail)
-)
-
-export skip := \list.\n. (
-  loop r on (list n) with
-    if n == 0 then list
-    else pop list end \head.\tail. r tail (n - 1)
-)
-
-export take := \list.\n. (
-  loop r on (list n) with
-    if n == 0 then end
-    else pop list end \head.\tail. cons head $ r tail $ n - 1
-)
-
-new[...$item, ...$rest:1] =0x2p84=> (cons (...$item) new[...$rest])
-new[...$end] =0x1p84=> (cons (...$end) end)
-new[] =0x1p84=> end
-
-export ::(new)

examples/list-processing/main.orc

@@ -1,6 +1,4 @@
-import std::(to_string, print)
+import std::(proc::*, io::print, to_string)
-import super::list
-import fn::*
 
 export main := do{
   let foo = list::new[1, 2, 3, 4, 5, 6];

examples/list-processing/option.orc

@@ -1,6 +0,0 @@
-export some := \v. \d.\f. f v
-export none := \d.\f. d
-
-export map := \option.\f. option none f
-export flatten := \option. option none \opt. opt
-export flatmap := \option.\f. option none \opt. map opt f

examples/maps/fn.orc

@@ -1,15 +0,0 @@
-export Y := \f.(\x.f (x x))(\x.f (x x))
-
-export loop $r on (..$parameters) with ...$tail =0x5p129=> Y (\$r.
-  bind_names (..$parameters) (...$tail)
-) ..$parameters
-
--- bind each of the names in the first argument as a parameter for the second argument
-bind_names ($name ..$rest) $payload =0x1p250=> \$name. bind_names (..$rest) $payload
-bind_names () (...$payload) =0x1p250=> ...$payload
-
-export ...$prefix $ ...$suffix:1 =0x1p34=> ...$prefix (...$suffix)
-export ...$prefix |> $fn ..$suffix:1 =0x2p32=> $fn (...$prefix) ..$suffix
-
-export (...$argv) => ...$body =0x2p129=> (bind_names (...$argv) (...$body))
-$name => ...$body =0x1p129=> (\$name. ...$body)

examples/maps/main.orc

@@ -1,8 +1,4 @@
-import list
+import std::(proc::*, io::print, to_string)
-import map
-import option
-import fn::*
-import std::(print, to_string)
 
 export main := do{
   let foo = map::new[

orchid.code-workspace

@@ -36,35 +36,13 @@
 	},
 	"extensions": {
 		"recommendations": [
-			"tomoki1207.pdf",
-			"james-yu.latex-workshop",
 			"bungcip.better-toml",
 			"maptz.regionfolder",
 			"serayuzgur.crates",
 			"tamasfe.even-better-toml",
-			"haskell.haskell",
-			"justusadam.language-haskell",
 			"yzhang.markdown-all-in-one",
-			"goessner.mdmath",
+			"gruntfuggly.todo-tree",
-			"gruntfuggly.todo-tree"
+			"vadimcn.vscode-lldb"
 		]
 	},
-	"launch": {
-		"version": "0.2.0",
-		"configurations": [
-			{
-				"type": "lldb",
-				"request": "launch",
-				"name": "Cargo launch",
-				"cwd": "${workspaceFolder:orchid}",
-				"program": "${workspaceFolder}/target/debug/orchid",
-				"cargo": {
-					"args": [
-						"run",
-					]
-				},
-				"args": []
-			}
-		]
-	}
 }

rustfmt.toml

@@ -12,7 +12,6 @@ newline_style = "Unix"
 normalize_comments = true
 wrap_comments = true
 overflow_delimited_expr = true
-single_line_if_else_max_width = 50
 use_small_heuristics = "Max"
 
 # literals

src/bin/cli/mod.rs

@@ -0,0 +1,2 @@
+mod prompt;
+pub use prompt::cmd_prompt;

src/bin/cli/prompt.rs

@@ -0,0 +1,11 @@
+use std::io::{self, Error, Write};
+
+pub fn cmd_prompt(prompt: &str) -> Result<(String, Vec<String>), Error> {
+  print!("{}", prompt);
+  io::stdout().flush()?;
+  let mut cmdln = String::new();
+  io::stdin().read_line(&mut cmdln)?;
+  let mut segments = cmdln.split(' ');
+  let cmd = if let Some(cmd) = segments.next() { cmd } else { "" };
+  Ok((cmd.to_string(), segments.map(str::to_string).collect()))
+}

src/bin/main.rs

@@ -1,127 +1,129 @@
-use std::borrow::Borrow;
+mod cli;
+
 use std::fs::File;
 use std::path::{Path, PathBuf};
-use std::rc::Rc;
+use std::process;
 
 use clap::Parser;
 use hashbrown::HashMap;
 use itertools::Itertools;
 use orchidlang::interner::{InternedDisplay, Interner, Sym};
-use orchidlang::pipeline::file_loader::{mk_cache, Loaded};
+use orchidlang::{ast, ast_to_interpreted, interpreter, pipeline, rule, stl};
-use orchidlang::pipeline::{
+
-  collect_consts, collect_rules, from_const_tree, parse_layer, ProjectTree,
+use crate::cli::cmd_prompt;
-};
-use orchidlang::rule::Repo;
-use orchidlang::sourcefile::{FileEntry, Import};
-use orchidlang::{ast_to_interpreted, interpreter, stl};
 
 /// Orchid interpreter
 #[derive(Parser, Debug)]
 #[command(author, version, about, long_about = None)]
 struct Args {
-  /// Folder containing main.orc
+  /// Folder containing main.orc or the manually specified entry module
   #[arg(short, long, default_value = ".")]
-  pub project: String,
+  pub dir: String,
+  /// Entrypoint for the interpreter
+  #[arg(short, long, default_value = "main::main")]
+  pub main: String,
+  /// Maximum number of steps taken by the macro executor
+  #[arg(long, default_value_t = 10_000)]
+  pub macro_limit: usize,
+  /// Print the parsed ruleset and exit
+  #[arg(long)]
+  pub dump_repo: bool,
+  /// Step through the macro execution process in the specified symbol
+  #[arg(long, default_value = "")]
+  pub macro_debug: String,
 }
 impl Args {
-  pub fn chk_proj(&self) -> Result<(), String> {
+  /// Validate the project directory and the
-    let mut path = PathBuf::from(&self.project);
+  pub fn chk_dir_main(&self) -> Result<(), String> {
-    path.push(PathBuf::from("main.orc"));
+    let dir_path = PathBuf::from(&self.dir);
-    if File::open(&path).is_ok() {
+    if !dir_path.is_dir() {
+      return Err(format!("{} is not a directory", dir_path.display()));
+    }
+    let segs = self.main.split("::").collect::<Vec<_>>();
+    if segs.len() < 2 {
+      return Err("Entry point too short".to_string());
+    }
+    let (pathsegs, _) = segs.split_at(segs.len() - 1);
+    let mut possible_files = pathsegs.iter().scan(dir_path, |path, seg| {
+      path.push(seg);
+      Some(path.with_extension("orc"))
+    });
+    if possible_files.all(|p| File::open(p).is_err()) {
+      return Err(format!(
+        "{} not found in {}",
+        pathsegs.join("::"),
+        PathBuf::from(&self.dir).display()
+      ));
+    }
     Ok(())
-    } else {
-      Err(format!("{} not found", path.display()))
   }
+
+  pub fn chk_proj(&self) -> Result<(), String> {
+    self.chk_dir_main()
   }
 }
 
-fn main() {
+/// Load and parse all source related to the symbol `target` or all symbols
-  let args = Args::parse();
+/// in the namespace `target` in the context of the STL. All sourcefiles must
-  args.chk_proj().unwrap_or_else(|e| panic!("{e}"));
+/// reside within `dir`.
-  run_dir(PathBuf::try_from(args.project).unwrap().borrow());
+fn load_dir(dir: &Path, target: Sym, i: &Interner) -> pipeline::ProjectTree {
-}
+  let file_cache = pipeline::file_loader::mk_dir_cache(dir.to_path_buf(), i);
-
+  let library = stl::mk_stl(i, stl::StlOptions::default());
-static PRELUDE_TXT: &str = r#"
+  pipeline::parse_layer(
-import std::(
+    &[target],
-  add, subtract, multiply, remainder, divide,
+    &|path| file_cache.find(&path),
-  equals, ifthenelse,
+    &library,
-  concatenate
+    &stl::mk_prelude(i),
-)
-
-export ...$a + ...$b =0x2p36=> (add (...$a) (...$b))
-export ...$a - ...$b:1 =0x2p36=> (subtract (...$a) (...$b))
-export ...$a * ...$b =0x1p36=> (multiply (...$a) (...$b))
-export ...$a % ...$b:1 =0x1p36=> (remainder (...$a) (...$b))
-export ...$a / ...$b:1 =0x1p36=> (divide (...$a) (...$b))
-export ...$a == ...$b =0x3p36=> (equals (...$a) (...$b))
-export ...$a ++ ...$b =0x4p36=> (concatenate (...$a) (...$b))
-
-export do { ...$statement ; ...$rest:1 } =0x2p130=> statement (...$statement) do { ...$rest }
-export do { ...$return } =0x1p130=> ...$return
-
-export statement (let $name = ...$value) ...$next =0x1p230=> (
-  (\$name. ...$next) (...$value)
-)
-export statement (cps $name = ...$operation) ...$next =0x2p230=> (
-  (...$operation) \$name. ...$next
-)
-export statement (cps ...$operation) ...$next =0x1p230=> (
-  (...$operation) (...$next)
-)
-
-export if ...$cond then ...$true else ...$false:1 =0x1p84=> (
-  ifthenelse (...$cond) (...$true) (...$false)
-)
-
-export ::(,)
-"#;
-
-fn prelude_path(i: &Interner) -> Sym {
-  i.i(&[i.i("prelude")][..])
-}
-fn mainmod_path(i: &Interner) -> Sym {
-  i.i(&[i.i("main")][..])
-}
-fn entrypoint(i: &Interner) -> Sym {
-  i.i(&[i.i("main"), i.i("main")][..])
-}
-
-fn load_environment(i: &Interner) -> ProjectTree {
-  let env = from_const_tree(
-    HashMap::from([(i.i("std"), stl::mk_stl(i))]),
-    &[i.i("std")],
     i,
-  );
-  let loader = |path: Sym| {
-    if path == prelude_path(i) {
-      Ok(Loaded::Code(Rc::new(PRELUDE_TXT.to_string())))
-    } else {
-      panic!(
-        "Prelude pointed to non-std path {}",
-        i.extern_vec(path).join("::")
   )
-    }
-  };
-  parse_layer(&[prelude_path(i)], &loader, &env, &[], i).expect("prelude error")
-}
-
-fn load_dir(i: &Interner, dir: &Path) -> ProjectTree {
-  let environment = load_environment(i);
-  let file_cache = mk_cache(dir.to_path_buf(), i);
-  let loader = |path| file_cache.find(&path);
-  let prelude =
-    [FileEntry::Import(vec![Import { path: prelude_path(i), name: None }])];
-  parse_layer(&[mainmod_path(i)], &loader, &environment, &prelude, i)
   .expect("Failed to load source code")
 }
 
-pub fn run_dir(dir: &Path) {
+pub fn to_sym(data: &str, i: &Interner) -> Sym {
+  i.i(&data.split("::").map(|s| i.i(s)).collect::<Vec<_>>()[..])
+}
+
+/// A little utility to step through the resolution of a macro set
+pub fn macro_debug(repo: rule::Repo, mut code: ast::Expr, i: &Interner) {
+  let mut idx = 0;
+  println!("Macro debugger working on {}", code.bundle(i));
+  loop {
+    let (cmd, _) = cmd_prompt("cmd> ").unwrap();
+    match cmd.trim() {
+      "" | "n" | "next" =>
+        if let Some(c) = repo.step(&code) {
+          idx += 1;
+          code = c;
+          println!("Step {idx}: {}", code.bundle(i));
+        },
+      "p" | "print" => println!("Step {idx}: {}", code.bundle(i)),
+      "d" | "dump" => println!("Rules: {}", repo.bundle(i)),
+      "q" | "quit" => return,
+      "h" | "help" => println!(
+        "Available commands:
+        \t<blank>, n, next\t\ttake a step
+        \tp, print\t\tprint the current state
+        \tq, quit\t\texit
+        \th, help\t\tprint this text"
+      ),
+      _ => {
+        println!("unrecognized command \"{}\", try \"help\"", cmd);
+        continue;
+      },
+    }
+  }
+}
+
+pub fn main() {
+  let args = Args::parse();
+  args.chk_proj().unwrap_or_else(|e| panic!("{e}"));
+  let dir = PathBuf::try_from(args.dir).unwrap();
   let i = Interner::new();
-  let project = load_dir(&i, dir);
+  let main = to_sym(&args.main, &i);
-  let rules = collect_rules(&project);
+  let project = load_dir(&dir, main, &i);
-  let consts = collect_consts(&project, &i);
+  let rules = pipeline::collect_rules(&project);
-  println!("Initializing rule repository with {} rules", rules.len());
+  let consts = pipeline::collect_consts(&project, &i);
-  let repo = Repo::new(rules, &i).unwrap_or_else(|(rule, error)| {
+  let repo = rule::Repo::new(rules, &i).unwrap_or_else(|(rule, error)| {
     panic!(
       "Rule error: {}
       Offending rule: {}",
@@ -129,42 +131,36 @@ pub fn run_dir(dir: &Path) {
       rule.bundle(&i)
     )
   });
-  println!("Repo dump: {}", repo.bundle(&i));
+  if args.dump_repo {
+    println!("Parsed rules: {}", repo.bundle(&i));
+    return;
+  } else if !args.macro_debug.is_empty() {
+    let name = to_sym(&args.macro_debug, &i);
+    let code = consts
+      .get(&name)
+      .unwrap_or_else(|| panic!("Constant {} not found", args.macro_debug));
+    return macro_debug(repo, code.clone(), &i);
+  }
   let mut exec_table = HashMap::new();
   for (name, source) in consts.iter() {
-    // let nval = entrypoint(&i); let name = &nval; let source = &consts[name];
-    let mut tree = source.clone();
     let displayname = i.extern_vec(*name).join("::");
-    let macro_timeout = 100;
+    let (unmatched, steps_left) = repo.long_step(source, args.macro_limit + 1);
-    println!("Executing macros in {displayname}...",);
+    assert!(steps_left > 0, "Macro execution in {displayname} did not halt");
-    let mut idx = 0;
+    let runtree = ast_to_interpreted(&unmatched).unwrap_or_else(|e| {
-    let unmatched = loop {
+      panic!("Postmacro conversion error in {displayname}: {e}")
-      if idx == macro_timeout {
+    });
-        panic!("Macro execution in {displayname} didn't halt")
-      }
-      match repo.step(&tree) {
-        None => break tree,
-        Some(phase) => {
-          println!("Step {idx}/{macro_timeout}: {}", phase.bundle(&i));
-          tree = phase;
-        },
-      }
-      idx += 1;
-    };
-    let runtree = ast_to_interpreted(&unmatched)
-      .unwrap_or_else(|e| panic!("Postmacro conversion error: {e}"));
     exec_table.insert(*name, runtree);
   }
-  println!("macro execution complete");
   let ctx =
     interpreter::Context { symbols: &exec_table, interner: &i, gas: None };
-  let entrypoint = exec_table.get(&entrypoint(&i)).unwrap_or_else(|| {
+  let entrypoint = exec_table.get(&main).unwrap_or_else(|| {
+    let main = args.main;
+    let symbols =
+      exec_table.keys().map(|t| i.extern_vec(*t).join("::")).join(", ");
     panic!(
-      "entrypoint not found, known keys are: {}",
+      "Entrypoint not found!
-      exec_table
+      Entrypoint was {main}
-        .keys()
+      known keys are {symbols}"
-        .map(|t| i.r(*t).iter().map(|t| i.r(*t)).join("::"))
-        .join(", ")
     )
   });
   let io_handler = orchidlang::stl::handleIO;
@@ -173,12 +169,11 @@ pub fn run_dir(dir: &Path) {
     ret.unwrap_or_else(|e| panic!("Runtime error: {}", e));
   if inert {
     println!("Settled at {}", state.expr().clause.bundle(&i));
-    println!(
+    if let Some(g) = gas {
-      "Remaining gas: {}",
+      println!("Remaining gas: {g}")
-      gas.map(|g| g.to_string()).unwrap_or(String::from("∞"))
-    );
     }
-  if gas == Some(0) {
+  } else if gas == Some(0) {
-    println!("Ran out of gas!")
+    eprintln!("Ran out of gas!");
+    process::exit(-1);
   }
 }

src/foreign_macros/atomic_impl.rs

@@ -6,14 +6,21 @@ use std::fmt::Debug;
 #[allow(unused)] // for the doc comments
 use dyn_clone::DynClone;
 
+#[allow(unused)] // for the doc comments
+use crate::define_fn;
 #[allow(unused)] // for the doc comments
 use crate::foreign::{Atomic, ExternFn};
 #[allow(unused)] // for the doc comments
+use crate::write_fn_step;
+#[allow(unused)] // for the doc comments
 use crate::Primitive;
 
 /// A macro that generates implementations of [Atomic] to simplify the
 /// development of external bindings for Orchid.
 ///
+/// Most use cases are fulfilled by [define_fn], pathological cases can combine
+/// [write_fn_step] with manual [Atomic] implementations.
+///
 /// The macro depends on implementations of [`AsRef<Clause>`] and
 /// [`From<(&Self, Clause)>`] for extracting the clause to be processed and then
 /// reconstructing the [Atomic]. Naturally, supertraits of [Atomic] are also
@@ -32,34 +39,35 @@ use crate::Primitive;
 ///
 /// _definition of the `add` function in the STL_
 /// ```
+/// use orchidlang::{Literal};
 /// use orchidlang::interpreted::ExprInst;
-/// use orchidlang::stl::Numeric;
+/// use orchidlang::stl::litconv::with_lit;
 /// use orchidlang::{atomic_impl, atomic_redirect, externfn_impl};
 ///
+/// /// Convert a literal to a string using Rust's conversions for floats, chars and
+/// /// uints respectively
 /// #[derive(Clone)]
-/// pub struct Add2;
+/// struct ToString;
-/// externfn_impl!(Add2, |_: &Self, x: ExprInst| Ok(Add1 { x }));
 ///
-/// #[derive(Debug, Clone)]
+/// externfn_impl!{
-/// pub struct Add1 {
+///   ToString, |_: &Self, expr_inst: ExprInst|{
-///   x: ExprInst,
+///     Ok(InternalToString {
+///       expr_inst
+///     })
 ///   }
-/// atomic_redirect!(Add1, x);
-/// atomic_impl!(Add1);
-/// externfn_impl!(Add1, |this: &Self, x: ExprInst| {
-///   let a: Numeric = this.x.clone().try_into()?;
-///   Ok(Add0 { a, x })
-/// });
-///
-/// #[derive(Debug, Clone)]
-/// pub struct Add0 {
-///   a: Numeric,
-///   x: ExprInst,
 /// }
-/// atomic_redirect!(Add0, x);
+/// #[derive(std::fmt::Debug,Clone)]
-/// atomic_impl!(Add0, |Self { a, x }: &Self, _| {
+/// struct InternalToString {
-///   let b: Numeric = x.clone().try_into()?;
+///   expr_inst: ExprInst,
-///   Ok((*a + b).into())
+/// }
+/// atomic_redirect!(InternalToString, expr_inst);
+/// atomic_impl!(InternalToString, |Self { expr_inst }: &Self, _|{
+///   with_lit(expr_inst, |l| Ok(match l {
+///     Literal::Char(c) => c.to_string(),
+///     Literal::Uint(i) => i.to_string(),
+///     Literal::Num(n) => n.to_string(),
+///     Literal::Str(s) => s.clone(),
+///   })).map(|s| Literal::Str(s).into())
 /// });
 /// ```
 #[macro_export]
@@ -92,7 +100,11 @@ macro_rules! atomic_impl {
         // branch off or wrap up
         let clause = if inert {
           let closure = $next_phase;
-          match closure(&next_self, ctx) {
+          let res: Result<
+            $crate::interpreted::Clause,
+            std::rc::Rc<dyn $crate::foreign::ExternError>,
+          > = closure(&next_self, ctx);
+          match res {
             Ok(r) => r,
             Err(e) => return Err($crate::interpreter::RuntimeError::Extern(e)),
           }

src/foreign_macros/define_fn.rs

@@ -26,6 +26,15 @@ use crate::write_fn_step;
 /// defined in the first step and returns a [Result] of the success type or
 /// `Rc<dyn ExternError>`.
 ///
+/// To avoid typing the same expression a lot, the conversion is optional.
+/// If it is omitted, the field is initialized with a [TryInto::try_into] call
+/// from `&ExprInst` to the target type. In this case, the error is
+/// short-circuited using `?` so conversions through `FromResidual` are allowed.
+/// The optional syntax starts with `as`.
+///
+/// If all conversions are omitted, the alias definition (`expr=$ident in`) has
+/// no effect and is therefore optional.
+///
 /// Finally, the body of the function is provided as an expression which can
 /// reference all of the arguments by their names, each bound to a ref of the
 /// specified type.
@@ -45,13 +54,59 @@ use crate::write_fn_step;
 ///   }
 /// }
 /// ```
+///
+/// A simpler format is also offered for unary functions:
+///
+/// ```
+/// use orchidlang::stl::litconv::with_lit;
+/// use orchidlang::{define_fn, Literal};
+///
+/// define_fn! {
+///   /// Convert a literal to a string using Rust's conversions for floats,
+///   /// chars and uints respectively
+///   ToString = |x| with_lit(x, |l| Ok(match l {
+///     Literal::Char(c) => c.to_string(),
+///     Literal::Uint(i) => i.to_string(),
+///     Literal::Num(n) => n.to_string(),
+///     Literal::Str(s) => s.clone(),
+///   })).map(|s| Literal::Str(s).into())
+/// }
+/// ```
 #[macro_export]
 macro_rules! define_fn {
+  // Unary function entry
+  ($( #[ $attr:meta ] )* $qual:vis $name:ident = $body:expr) => {paste::paste!{
+    $crate::write_fn_step!(
+      $( #[ $attr ] )* $qual $name
+      >
+      [< Internal $name >]
+    );
+    $crate::write_fn_step!(
+      [< Internal $name >]
+      {}
+      out = expr => Ok(expr);
+      {
+        let lambda = $body;
+        lambda(out)
+      }
+    );
+  }};
+  // xname is optional only if every conversion is implicit
+  ($( #[ $attr:meta ] )* $qual:vis $name:ident {
+    $( $arg:ident: $typ:ty ),+
+  } => $body:expr) => {
+    $crate::define_fn!{expr=expr in
+      $( #[ $attr ] )* $qual $name {
+        $( $arg: $typ ),*
+      } => $body
+    }
+  };
+  // multi-parameter function entry
   (expr=$xname:ident in
     $( #[ $attr:meta ] )*
     $qual:vis $name:ident {
-      $arg0:ident: $typ0:ty as $parse0:expr
+      $arg0:ident: $typ0:ty $( as $parse0:expr )?
-      $(, $arg:ident: $typ:ty as $parse:expr )*
+      $(, $arg:ident: $typ:ty $( as $parse:expr )? )*
     } => $body:expr
   ) => {paste::paste!{
     // Generate initial state
@@ -64,8 +119,10 @@ macro_rules! define_fn {
     $crate::define_fn!(@MIDDLE $xname [< Internal $name >] ($body)
       ()
       (
-        ($arg0: $typ0 as $parse0)
+        ( $arg0: $typ0 $( as $parse0)? )
-        $( ($arg: $typ as $parse) )*
+        $(
+          ( $arg: $typ $( as $parse)? )
+        )*
       )
     );
   }};
@@ -80,10 +137,10 @@ macro_rules! define_fn {
     // later fields
     (
       // field that should be processed by this step
-      ( $arg0:ident: $typ0:ty as $parse0:expr )
+      ( $arg0:ident: $typ0:ty $( as $parse0:expr )? )
       // ensure that we have a next stage
       $(
-        ( $arg:ident: $typ:ty as $parse:expr )
+        ( $arg:ident: $typ:ty $( as $parse:expr )? )
       )+
     )
   ) => {paste::paste!{
@@ -93,7 +150,7 @@ macro_rules! define_fn {
         $( $arg_prev:ident : $typ_prev:ty ),*
       }
       [< $name $arg0:upper >]
-      where $arg0:$typ0 = $xname => $parse0;
+      where $arg0:$typ0 $( = $xname => $parse0 )? ;
     );
     $crate::define_fn!(@MIDDLE $xname [< $name $arg0:upper >] ($body)
       (
@@ -101,7 +158,9 @@ macro_rules! define_fn {
         ($arg0: $typ0)
       )
       (
-        $( ($arg: $typ as $parse) )+
+        $(
+          ( $arg: $typ $( as $parse)? )
+        )+
       )
     );
   }};
@@ -113,7 +172,7 @@ macro_rules! define_fn {
     )
     // the last one is initialized before the body runs
     (
-      ($arg0:ident: $typ0:ty as $parse0:expr)
+      ($arg0:ident: $typ0:ty $( as $parse0:expr )? )
     )
   ) => {
     $crate::write_fn_step!(
@@ -121,7 +180,7 @@ macro_rules! define_fn {
       {
         $( $arg_prev: $typ_prev ),*
       }
-      $arg0:$typ0 = $xname => $parse0;
+      $arg0:$typ0 $( = $xname => $parse0 )? ;
       $body
     );
   };

src/foreign_macros/write_fn_step.rs

@@ -1,13 +1,17 @@
 #[allow(unused)] // for doc
 use crate::define_fn;
 #[allow(unused)] // for doc
+use crate::foreign::Atomic;
+#[allow(unused)] // for doc
 use crate::foreign::ExternFn;
 #[allow(unused)] // for doc
 use crate::interpreted::ExprInst;
 
 /// Write one step in the state machine representing a simple n-ary non-variadic
-/// Orchid function. There are no known use cases for it that aren't expressed
+/// Orchid function. Most use cases are better covered by [define_fn] which
-/// better with [define_fn] which generates calls to this macro.
+/// generates calls to this macro. This macro can be used in combination with
+/// manual [Atomic] implementations to define a function that only behaves like
+/// a simple n-ary non-variadic function with respect to some of its arguments.
 ///
 /// There are three ways to call this macro for the initial state, internal
 /// state, and exit state. All of them are demonstrated in one example and
@@ -25,14 +29,14 @@ use crate::interpreted::ExprInst;
 /// // Middle state
 /// write_fn_step!(
 ///   CharAt1 {}
-///   CharAt0 where s = x => with_str(x, |s| Ok(s.clone()));
+///   CharAt0 where s: String = x => with_str(x, |s| Ok(s.clone()));
 /// );
 /// // Exit state
 /// write_fn_step!(
 ///   CharAt0 { s: String }
 ///   i = x => with_uint(x, Ok);
 ///   {
-///     if let Some(c) = s.chars().nth(i as usize) {
+///     if let Some(c) = s.chars().nth(*i as usize) {
 ///       Ok(Clause::P(Primitive::Literal(Literal::Char(c))))
 ///     } else {
 ///       RuntimeError::fail(
@@ -52,7 +56,7 @@ use crate::interpreted::ExprInst;
 /// struct definition. A field called `expr_inst` of type [ExprInst] is added
 /// implicitly, so the first middle state has an empty field list. The next
 /// state is also provided, alongside the name and conversion of the next
-/// parameter from a [&ExprInst] under the provided alias to a
+/// parameter from a `&ExprInst` under the provided alias to a
 /// `Result<_, Rc<dyn ExternError>>`. The success type is inferred from the
 /// type of the field at the place of its actual definition. This conversion is
 /// done in the implementation of [ExternFn] which also places the new
@@ -67,6 +71,12 @@ use crate::interpreted::ExprInst;
 /// argument names bound. The arguments here are all references to their actual
 /// types except for the last one which is converted from [ExprInst] immediately
 /// before the body is evaluated.
+///
+/// To avoid typing the same parsing process a lot, the conversion is optional.
+/// If it is omitted, the field is initialized with a [TryInto::try_into] call
+/// from `&ExprInst` to the target type. In this case, the error is
+/// short-circuited using `?` so conversions through `FromResidual` are allowed.
+/// The optional syntax starts with the `=` sign and ends before the semicolon.
 #[macro_export]
 macro_rules! write_fn_step {
   // write entry stage
@@ -87,7 +97,7 @@ macro_rules! write_fn_step {
       $( $arg:ident : $typ:ty ),*
     }
     $next:ident where
-    $added:ident $( : $added_typ:ty )? = $xname:ident => $extract:expr ;
+    $added:ident $( : $added_typ:ty )? $( = $xname:ident => $extract:expr )? ;
   ) => {
     $( #[ $attr ] )*
     #[derive(std::fmt::Debug, Clone)]
@@ -100,8 +110,8 @@ macro_rules! write_fn_step {
     $crate::externfn_impl!(
       $name,
       |this: &Self, expr_inst: $crate::interpreted::ExprInst| {
-        let $xname = &this.expr_inst;
+        let $added $( :$added_typ )? =
-        let $added $( :$added_typ )? = $extract?;
+          $crate::write_fn_step!(@CONV &this.expr_inst $(, $xname $extract )?);
         Ok($next{
           $( $arg: this.$arg.clone(), )*
           $added, expr_inst
@@ -114,23 +124,37 @@ macro_rules! write_fn_step {
     $( #[ $attr:meta ] )* $quant:vis $name:ident {
       $( $arg:ident: $typ:ty ),*
     }
-    $added:ident $(: $added_typ:ty )? = $xname:ident => $extract:expr ;
+    $added:ident $(: $added_typ:ty )? $( = $xname:ident => $extract:expr )? ;
     $process:expr
   ) => {
     $( #[ $attr ] )*
     #[derive(std::fmt::Debug, Clone)]
     $quant struct $name {
-      $( $arg: $typ, )+
+      $( $arg: $typ, )*
       expr_inst: $crate::interpreted::ExprInst,
     }
     $crate::atomic_redirect!($name, expr_inst);
     $crate::atomic_impl!(
       $name,
       |Self{ $($arg, )* expr_inst }: &Self, _| {
-        let $xname = expr_inst;
+        let added $(: $added_typ )? =
-        let $added $(: $added_typ )? = $extract?;
+          $crate::write_fn_step!(@CONV expr_inst $(, $xname $extract )?);
+        let $added = &added;
         $process
       }
     );
   };
+  // Write conversion expression for an ExprInst
+  (@CONV $locxname:expr, $xname:ident $extract:expr) => {
+    {
+      let $xname = $locxname;
+      match $extract {
+        Err(e) => return Err(e),
+        Ok(r) => r,
+      }
+    }
+  };
+  (@CONV $locxname:expr) => {
+    ($locxname).try_into()?
+  };
 }

src/interner/monotype.rs

@@ -52,7 +52,7 @@ impl<T: Eq + Hash + Clone> TypedInterner<T> {
   pub fn r(&self, t: Tok<T>) -> &T {
     let values = self.values.borrow();
     let key = t.into_usize() - 1;
-    values[key].0
+    values[key].0.borrow()
   }
 
   /// Intern a static reference without allocating the data on the heap
@@ -91,7 +91,7 @@ impl<T: Eq + Hash + Clone> Drop for TypedInterner<T> {
       if !owned {
         continue;
       }
-      unsafe { Box::from_raw((item as *const T).cast_mut()) };
+      let _ = unsafe { Box::from_raw((item as *const T).cast_mut()) };
     }
   }
 }

src/lib.rs

@@ -18,6 +18,7 @@ pub mod rule;
 pub mod stl;
 mod utils;
 
+pub use interner::Sym;
 pub use representations::ast_to_interpreted::ast_to_interpreted;
 pub use representations::{
   ast, interpreted, sourcefile, tree, Literal, Location, PathSet, Primitive,

src/parse/import.rs

@@ -83,11 +83,7 @@ pub fn import_parser<'a>(
         Some(Import {
           path: ctx.interner().i(&path),
           name: {
-            if name == ctx.interner().i("*") {
+            if name == ctx.interner().i("*") { None } else { Some(name) }
-              None
-            } else {
-              Some(name)
-            }
           },
         })
       })

src/parse/lexer.rs

@@ -115,11 +115,7 @@ impl InternedDisplay for Lexeme {
       Self::PH(Placeholder { name, class }) => match *class {
         PHClass::Scalar => write!(f, "${}", i.r(*name)),
         PHClass::Vec { nonzero, prio } => {
-          if nonzero {
+          if nonzero { write!(f, "...") } else { write!(f, "..") }?;
-            write!(f, "...")
-          } else {
-            write!(f, "..")
-          }?;
           write!(f, "${}", i.r(*name))?;
           if prio != 0 {
             write!(f, ":{}", prio)?;

src/pipeline/file_loader.rs

@@ -1,8 +1,11 @@
-//! File system implementation of the source loader callback
+//! Source loader callback definition and builtin implementations
 use std::path::{Path, PathBuf};
 use std::rc::Rc;
 use std::{fs, io};
 
+use chumsky::text::Character;
+use rust_embed::RustEmbed;
+
 use crate::interner::{Interner, Sym};
 use crate::pipeline::error::{
   ErrorPosition, ProjectError, UnexpectedDirectory,
@@ -86,13 +89,52 @@ pub fn load_file(root: &Path, path: &[impl AsRef<str>]) -> IOResult {
 }
 
 /// Generates a cached file loader for a directory
-pub fn mk_cache(root: PathBuf, i: &Interner) -> Cache<Sym, IOResult> {
+pub fn mk_dir_cache(root: PathBuf, i: &Interner) -> Cache<Sym, IOResult> {
   Cache::new(move |token: Sym, _this| -> IOResult {
     let path = i.r(token).iter().map(|t| i.r(*t).as_str()).collect::<Vec<_>>();
     load_file(&root, &path)
   })
 }
 
+/// Load a file from the specified path from an embed table
+pub fn load_embed<T: 'static + RustEmbed>(path: &str, ext: &str) -> IOResult {
+  let file_path = path.to_string() + ext;
+  if let Some(file) = T::get(&file_path) {
+    let s = file.data.iter().map(|c| c.to_char()).collect::<String>();
+    Ok(Loaded::Code(Rc::new(s)))
+  } else {
+    let entries = T::iter()
+      .map(|c| c.to_string())
+      .filter_map(|path: String| {
+        let item_prefix = path.to_string() + "/";
+        path.strip_prefix(&item_prefix).map(|subpath| {
+          let item_name = subpath
+            .split_inclusive('/')
+            .next()
+            .expect("Exact match excluded earlier");
+          item_name
+            .strip_suffix('/') // subdirectory
+            .or_else(|| item_name.strip_suffix(ext)) // file
+            .expect("embed should be filtered to extension")
+            .to_string()
+        })
+      })
+      .collect::<Vec<String>>();
+    Ok(Loaded::Collection(Rc::new(entries)))
+  }
+}
+
+/// Generates a cached file loader for a [RustEmbed]
+pub fn mk_embed_cache<'a, T: 'static + RustEmbed>(
+  ext: &'a str,
+  i: &'a Interner,
+) -> Cache<'a, Sym, IOResult> {
+  Cache::new(move |token: Sym, _this| -> IOResult {
+    let path = i.extern_vec(token).join("/");
+    load_embed::<T>(&path, ext)
+  })
+}
+
 /// Loads the string contents of a file at the given location.
 /// If the path points to a directory, raises an error.
 pub fn load_text(

src/pipeline/import_resolution/apply_aliases.rs

@@ -3,14 +3,14 @@ use std::rc::Rc;
 use hashbrown::HashMap;
 
 use super::alias_map::AliasMap;
-use super::decls::InjectedAsFn;
+use super::decls::{InjectedAsFn, UpdatedFn};
 use crate::ast::{Expr, Rule};
 use crate::interner::{Interner, Sym, Tok};
 use crate::pipeline::{ProjectExt, ProjectModule};
 use crate::representations::tree::{ModEntry, ModMember};
 use crate::utils::Substack;
 
-fn resolve(
+fn resolve_rec(
   token: Sym,
   alias_map: &AliasMap,
   i: &Interner,
@@ -18,7 +18,7 @@ fn resolve(
   if let Some(alias) = alias_map.resolve(token) {
     Some(i.r(alias).clone())
   } else if let Some((foot, body)) = i.r(token).split_last() {
-    let mut new_beginning = resolve(i.i(body), alias_map, i)?;
+    let mut new_beginning = resolve_rec(i.i(body), alias_map, i)?;
     new_beginning.push(*foot);
     Some(new_beginning)
   } else {
@@ -26,6 +26,18 @@ fn resolve(
   }
 }
 
+fn resolve(
+  token: Sym,
+  alias_map: &AliasMap,
+  injected_as: &impl InjectedAsFn,
+  i: &Interner,
+) -> Option<Sym> {
+  injected_as(&i.r(token)[..]).or_else(|| {
+    let next_v = resolve_rec(token, alias_map, i)?;
+    Some(injected_as(&next_v).unwrap_or_else(|| i.i(&next_v)))
+  })
+}
+
 fn process_expr(
   expr: &Expr,
   alias_map: &AliasMap,
@@ -33,16 +45,7 @@ fn process_expr(
   i: &Interner,
 ) -> Expr {
   expr
-    .map_names(&|n| {
+    .map_names(&|n| resolve(n, alias_map, injected_as, i))
-      injected_as(&i.r(n)[..]).or_else(|| {
-        let next_v = resolve(n, alias_map, i)?;
-        // println!("Resolved alias {} to {}",
-        //   i.extern_vec(n).join("::"),
-        //   i.extern_all(&next_v).join("::")
-        // );
-        Some(injected_as(&next_v).unwrap_or_else(|| i.i(&next_v)))
-      })
-    })
     .unwrap_or_else(|| expr.clone())
 }
 
@@ -54,10 +57,9 @@ fn apply_aliases_rec(
   alias_map: &AliasMap,
   i: &Interner,
   injected_as: &impl InjectedAsFn,
+  updated: &impl UpdatedFn,
 ) -> ProjectModule {
-  let items = module
+  let items = (module.items.iter())
-    .items
-    .iter()
     .map(|(name, ent)| {
       let ModEntry { exported, member } = ent;
       let member = match member {
@@ -65,9 +67,7 @@ fn apply_aliases_rec(
           ModMember::Item(process_expr(expr, alias_map, injected_as, i)),
         ModMember::Sub(module) => {
           let subpath = path.push(*name);
-          let is_ignored =
+          let new_mod = if !updated(&subpath.iter().rev_vec_clone()) {
-            injected_as(&subpath.iter().rev_vec_clone()).is_some();
-          let new_mod = if is_ignored {
             module.clone()
           } else {
             let module = module.as_ref();
@@ -77,6 +77,7 @@ fn apply_aliases_rec(
               alias_map,
               i,
               injected_as,
+              updated,
             ))
           };
           ModMember::Sub(new_mod)
@@ -85,23 +86,18 @@ fn apply_aliases_rec(
       (*name, ModEntry { exported: *exported, member })
     })
     .collect::<HashMap<_, _>>();
-  let rules = module
+  let rules = (module.extra.rules.iter())
-    .extra
-    .rules
-    .iter()
     .map(|rule| {
       let Rule { pattern, prio, template } = rule;
       Rule {
         prio: *prio,
         pattern: Rc::new(
-          pattern
+          (pattern.iter())
-            .iter()
             .map(|expr| process_expr(expr, alias_map, injected_as, i))
             .collect::<Vec<_>>(),
         ),
         template: Rc::new(
-          template
+          (template.iter())
-            .iter()
             .map(|expr| process_expr(expr, alias_map, injected_as, i))
             .collect::<Vec<_>>(),
         ),
@@ -113,7 +109,11 @@ fn apply_aliases_rec(
     imports: module.imports.clone(),
     extra: ProjectExt {
       rules,
-      exports: module.extra.exports.clone(),
+      exports: (module.extra.exports.iter())
+        .map(|(k, v)| {
+          (*k, resolve(*v, alias_map, injected_as, i).unwrap_or(*v))
+        })
+        .collect(),
       file: module.extra.file.clone(),
       imports_from: module.extra.imports_from.clone(),
     },
@@ -125,6 +125,14 @@ pub fn apply_aliases(
   alias_map: &AliasMap,
   i: &Interner,
   injected_as: &impl InjectedAsFn,
+  updated: &impl UpdatedFn,
 ) -> ProjectModule {
-  apply_aliases_rec(Substack::Bottom, module, alias_map, i, injected_as)
+  apply_aliases_rec(
+    Substack::Bottom,
+    module,
+    alias_map,
+    i,
+    injected_as,
+    updated,
+  )
 }

src/pipeline/import_resolution/collect_aliases.rs

@@ -1,12 +1,13 @@
+use core::panic;
 use std::rc::Rc;
 
 use super::alias_map::AliasMap;
-use super::decls::InjectedAsFn;
+use super::decls::UpdatedFn;
 use crate::interner::{Interner, Tok};
 use crate::pipeline::error::{NotExported, ProjectError};
 use crate::pipeline::project_tree::{split_path, ProjectModule, ProjectTree};
 use crate::representations::tree::{ModMember, WalkErrorKind};
-use crate::utils::{pushed, Substack};
+use crate::utils::{pushed, unwrap_or, Substack};
 
 /// Assert that a module identified by a path can see a given symbol
 fn assert_visible(
@@ -15,18 +16,24 @@ fn assert_visible(
   project: &ProjectTree,
   i: &Interner,
 ) -> Result<(), Rc<dyn ProjectError>> {
-  let (tgt_item, tgt_path) = if let Some(s) = target.split_last() {
+  let (tgt_item, tgt_path) = unwrap_or!(target.split_last(); return Ok(()));
-    s
-  } else {
-    return Ok(());
-  };
   let shared_len =
     source.iter().zip(tgt_path.iter()).take_while(|(a, b)| a == b).count();
-  let shared_root =
+  let vis_ignored_len = usize::min(tgt_path.len(), shared_len + 1);
-    project.0.walk(&tgt_path[..shared_len], false).expect("checked in parsing");
+  let private_root =
-  let direct_parent =
+    (project.0).walk(&tgt_path[..vis_ignored_len], false).unwrap_or_else(|e| {
-    shared_root.walk(&tgt_path[shared_len..], true).map_err(|e| {
+      let path_slc = &tgt_path[..vis_ignored_len];
-      match e.kind {
+      let bad_path = i.extern_all(path_slc).join("::");
+      eprintln!(
+        "Error while walking {bad_path}; {:?} on step {}",
+        e.kind, e.pos
+      );
+      eprintln!("looking from {}", i.extern_all(source).join("::"));
+      panic!("")
+    });
+  let direct_parent = private_root
+    .walk(&tgt_path[vis_ignored_len..], true)
+    .map_err(|e| match e.kind {
       WalkErrorKind::Missing => panic!("checked in parsing"),
       WalkErrorKind::Private => {
         let full_path = &tgt_path[..shared_len + e.pos];
@@ -40,11 +47,9 @@ fn assert_visible(
         }
         .rc()
       },
-      }
     })?;
   let tgt_item_exported = direct_parent.extra.exports.contains_key(tgt_item);
-  let target_prefixes_source =
+  let target_prefixes_source = shared_len == tgt_path.len();
-    shared_len == tgt_path.len() && source.get(shared_len) == Some(tgt_item);
   if !tgt_item_exported && !target_prefixes_source {
     let (file, sub) = split_path(target, project);
     let (ref_file, ref_sub) = split_path(source, project);
@@ -69,20 +74,30 @@ fn collect_aliases_rec(
   project: &ProjectTree,
   alias_map: &mut AliasMap,
   i: &Interner,
-  injected_as: &impl InjectedAsFn,
+  updated: &impl UpdatedFn,
 ) -> Result<(), Rc<dyn ProjectError>> {
   // Assume injected module has been alias-resolved
   let mod_path_v = path.iter().rev_vec_clone();
-  if injected_as(&mod_path_v).is_some() {
+  if !updated(&mod_path_v) {
     return Ok(());
   };
-  for (&name, &target_mod) in module.extra.imports_from.iter() {
+  for (&name, &target_mod_name) in module.extra.imports_from.iter() {
-    let target_mod_v = i.r(target_mod);
+    let target_mod_v = i.r(target_mod_name);
     let target_sym_v = pushed(target_mod_v, name);
     assert_visible(&mod_path_v, &target_sym_v, project, i)?;
     let sym_path_v = pushed(&mod_path_v, name);
     let sym_path = i.i(&sym_path_v);
-    let target_sym = i.i(&target_sym_v);
+    let target_mod = (project.0.walk(target_mod_v, false))
+      .expect("checked above in assert_visible");
+    let target_sym =
+      *target_mod.extra.exports.get(&name).unwrap_or_else(|| {
+        panic!(
+          "error in {}, {} has no member {}",
+          i.extern_all(&mod_path_v).join("::"),
+          i.extern_all(target_mod_v).join("::"),
+          i.r(name)
+        )
+      });
     alias_map.link(sym_path, target_sym);
   }
   for (&name, entry) in module.items.iter() {
@@ -97,7 +112,7 @@ fn collect_aliases_rec(
       project,
       alias_map,
       i,
-      injected_as,
+      updated,
     )?
   }
   Ok(())
@@ -109,14 +124,7 @@ pub fn collect_aliases(
   project: &ProjectTree,
   alias_map: &mut AliasMap,
   i: &Interner,
-  injected_as: &impl InjectedAsFn,
+  updated: &impl UpdatedFn,
 ) -> Result<(), Rc<dyn ProjectError>> {
-  collect_aliases_rec(
+  collect_aliases_rec(Substack::Bottom, module, project, alias_map, i, updated)
-    Substack::Bottom,
-    module,
-    project,
-    alias_map,
-    i,
-    injected_as,
-  )
 }

src/pipeline/import_resolution/decls.rs

@@ -4,4 +4,5 @@ use crate::interner::{Sym, Tok};
 
 trait_set! {
   pub trait InjectedAsFn = Fn(&[Tok<String>]) -> Option<Sym>;
+  pub trait UpdatedFn = Fn(&[Tok<String>]) -> bool;
 }

src/pipeline/import_resolution/resolve_imports.rs

@@ -1,11 +1,9 @@
 use std::rc::Rc;
 
-use itertools::Itertools;
-
 use super::alias_map::AliasMap;
 use super::apply_aliases::apply_aliases;
 use super::collect_aliases::collect_aliases;
-use super::decls::InjectedAsFn;
+use super::decls::{InjectedAsFn, UpdatedFn};
 use crate::interner::Interner;
 use crate::pipeline::error::ProjectError;
 use crate::pipeline::project_tree::ProjectTree;
@@ -16,21 +14,11 @@ pub fn resolve_imports(
   project: ProjectTree,
   i: &Interner,
   injected_as: &impl InjectedAsFn,
+  updated: &impl UpdatedFn,
 ) -> Result<ProjectTree, Rc<dyn ProjectError>> {
   let mut map = AliasMap::new();
-  collect_aliases(project.0.as_ref(), &project, &mut map, i, injected_as)?;
+  collect_aliases(project.0.as_ref(), &project, &mut map, i, updated)?;
-  println!(
+  let new_mod =
-    "Aliases: {{{:?}}}",
+    apply_aliases(project.0.as_ref(), &map, i, injected_as, updated);
-    map
-      .targets
-      .iter()
-      .map(|(kt, vt)| format!(
-        "{} => {}",
-        i.extern_vec(*kt).join("::"),
-        i.extern_vec(*vt).join("::")
-      ))
-      .join(", ")
-  );
-  let new_mod = apply_aliases(project.0.as_ref(), &map, i, injected_as);
   Ok(ProjectTree(Rc::new(new_mod)))
 }

src/pipeline/mod.rs

@@ -6,7 +6,6 @@ mod import_resolution;
 mod parse_layer;
 mod project_tree;
 mod source_loader;
-mod split_name;
 
 pub use parse_layer::parse_layer;
 pub use project_tree::{

src/pipeline/parse_layer.rs

@@ -34,13 +34,16 @@ pub fn parse_layer(
   };
   let source =
     source_loader::load_source(targets, prelude, i, loader, &|path| {
-      injected_as(path).is_some()
+      environment.0.walk(&i.r(path)[..], false).is_ok()
     })?;
   let tree = project_tree::build_tree(source, i, prelude, &injected_names)?;
   let sum = ProjectTree(Rc::new(
-    environment.0.as_ref().clone() + tree.0.as_ref().clone(),
+    environment.0.as_ref().clone().overlay(tree.0.as_ref().clone()),
   ));
-  let resolvd = import_resolution::resolve_imports(sum, i, &injected_as)?;
+  let resolvd =
+    import_resolution::resolve_imports(sum, i, &injected_as, &|path| {
+      tree.0.walk(path, false).is_ok()
+    })?;
   // Addition among modules favours the left hand side.
   Ok(resolvd)
 }

src/pipeline/project_tree/build_tree.rs

@@ -57,11 +57,7 @@ fn source_to_module(
   let imports = data
     .iter()
     .filter_map(|ent| {
-      if let FileEntry::Import(impv) = ent {
+      if let FileEntry::Import(impv) = ent { Some(impv.iter()) } else { None }
-        Some(impv.iter())
-      } else {
-        None
-      }
     })
     .flatten()
     .cloned()
@@ -182,6 +178,10 @@ fn files_to_module(
   i: &Interner,
 ) -> Rc<Module<Expr, ProjectExt>> {
   let lvl = path.len();
+  debug_assert!(
+    files.iter().map(|f| f.path.len()).max().unwrap() >= lvl,
+    "path is longer than any of the considered file paths"
+  );
   let path_v = path.iter().rev_vec_clone();
   if files.len() == 1 && files[0].path.len() == lvl {
     return source_to_module(
@@ -227,6 +227,7 @@ pub fn build_tree(
   prelude: &[FileEntry],
   injected: &impl InjectedOperatorsFn,
 ) -> Result<ProjectTree, Rc<dyn ProjectError>> {
+  assert!(!files.is_empty(), "A tree requires at least one module");
   let ops_cache = collect_ops::mk_cache(&files, i, injected);
   let mut entries = files
     .iter()

src/pipeline/project_tree/collect_ops/exported_ops.rs

@@ -1,16 +1,13 @@
-use std::println;
 use std::rc::Rc;
 
 use hashbrown::HashSet;
-use itertools::Itertools;
 use trait_set::trait_set;
 
 use crate::interner::{Interner, Sym, Tok};
 use crate::pipeline::error::{ModuleNotFound, ProjectError};
 use crate::pipeline::source_loader::LoadedSourceTable;
-use crate::pipeline::split_name::split_name;
 use crate::representations::tree::WalkErrorKind;
-use crate::utils::Cache;
+use crate::utils::{split_max_prefix, unwrap_or, Cache};
 
 pub type OpsResult = Result<Rc<HashSet<Tok<String>>>, Rc<dyn ProjectError>>;
 pub type ExportedOpsCache<'a> = Cache<'a, Sym, OpsResult>;
@@ -33,22 +30,12 @@ pub fn collect_exported_ops(
   i: &Interner,
   injected: &impl InjectedOperatorsFn,
 ) -> OpsResult {
-  if let Some(ops) = injected(path) {
+  let injected = injected(path).unwrap_or_else(|| Rc::new(HashSet::new()));
-    if path == i.i(&[i.i("prelude")][..]) {
-      println!("%%% Prelude exported ops %%%");
-      println!("{}", ops.iter().map(|t| i.r(*t)).join(", "));
-    }
-    return Ok(ops);
-  }
   let is_file = |n: &[Tok<String>]| loaded.contains_key(&i.i(n));
   let path_s = &i.r(path)[..];
-  let name_split = split_name(path_s, &is_file);
+  let name_split = split_max_prefix(path_s, &is_file);
-  let (fpath_v, subpath_v) = if let Some(f) = name_split {
+  let (fpath_v, subpath_v) = unwrap_or!(name_split; return Ok(Rc::new(
-    f
+    (loaded.keys())
-  } else {
-    return Ok(Rc::new(
-      loaded
-        .keys()
       .copied()
       .filter_map(|modname| {
         let modname_s = i.r(modname);
@@ -58,9 +45,9 @@ pub fn collect_exported_ops(
           None
         }
       })
+      .chain(injected.iter().copied())
       .collect::<HashSet<_>>(),
-    ));
+  )));
-  };
   let fpath = i.i(fpath_v);
   let preparsed = &loaded[&fpath].preparsed;
   let module = preparsed.0.walk(subpath_v, false).map_err(|walk_err| {
@@ -70,8 +57,7 @@ pub fn collect_exported_ops(
       },
       WalkErrorKind::Missing => ModuleNotFound {
         file: i.extern_vec(fpath),
-        subpath: subpath_v
+        subpath: (subpath_v.iter())
-          .iter()
           .take(walk_err.pos)
           .map(|t| i.r(*t))
           .cloned()
@@ -80,12 +66,11 @@ pub fn collect_exported_ops(
       .rc(),
     }
   })?;
-  let out: HashSet<_> =
+  let out = (module.items.iter())
-    module.items.iter().filter(|(_, v)| v.exported).map(|(k, _)| *k).collect();
+    .filter(|(_, v)| v.exported)
-  if path == i.i(&[i.i("prelude")][..]) {
+    .map(|(k, _)| *k)
-    println!("%%% Prelude exported ops %%%");
+    .chain(injected.iter().copied())
-    println!("{}", out.iter().map(|t| i.r(*t)).join(", "));
+    .collect::<HashSet<_>>();
-  }
   Ok(Rc::new(out))
 }
 

src/pipeline/project_tree/collect_ops/ops_for.rs

@@ -1,7 +1,6 @@
 use std::rc::Rc;
 
 use hashbrown::HashSet;
-use itertools::Itertools;
 
 use super::exported_ops::{ExportedOpsCache, OpsResult};
 use crate::interner::{Interner, Tok};
@@ -34,13 +33,11 @@ pub fn collect_ops_for(
 ) -> OpsResult {
   let tree = &loaded[&i.i(file)].preparsed.0;
   let mut ret = HashSet::new();
-  println!("collecting ops for {}", i.extern_all(file).join("::"));
   tree_all_ops(tree.as_ref(), &mut ret);
   tree.visit_all_imports(&mut |modpath, _module, import| {
     if let Some(n) = import.name {
       ret.insert(n);
     } else {
-      println!("\tglob import from {}", i.extern_vec(import.path).join("::"));
       let path = import_abs_path(file, modpath, &i.r(import.path)[..], i)
         .expect("This error should have been caught during loading");
       ret.extend(ops_cache.find(&i.i(&path))?.iter().copied());
@@ -48,9 +45,5 @@ pub fn collect_ops_for(
     Ok::<_, Rc<dyn ProjectError>>(())
   })?;
   ret.drain_filter(|t| !is_op(i.r(*t)));
-  if file == &[i.i("map")][..] {
-    println!(" %%% ops in map %%% ");
-    println!("{}", ret.iter().map(|t| i.r(*t)).join(", "))
-  }
   Ok(Rc::new(ret))
 }

src/pipeline/project_tree/tree.rs

@@ -41,6 +41,7 @@ impl Add for ProjectExt {
 pub type ProjectModule = Module<Expr, ProjectExt>;
 
 /// Module corresponding to the root of a project
+#[derive(Debug, Clone)]
 pub struct ProjectTree(pub Rc<ProjectModule>);
 
 fn collect_rules_rec(bag: &mut Vec<Rule>, module: &ProjectModule) {

src/pipeline/source_loader/load_source.rs

@@ -3,12 +3,12 @@ use std::rc::Rc;
 
 use super::loaded_source::{LoadedSource, LoadedSourceTable};
 use super::preparse::preparse;
-use crate::interner::{Interner, Sym, Tok};
+use crate::interner::{Interner, Sym};
 use crate::pipeline::error::ProjectError;
 use crate::pipeline::file_loader::{load_text, IOResult, Loaded};
 use crate::pipeline::import_abs_path::import_abs_path;
-use crate::pipeline::split_name::split_name;
 use crate::representations::sourcefile::FileEntry;
+use crate::utils::split_max_prefix;
 
 /// Load the source at the given path or all within if it's a collection,
 /// and all sources imported from these.
@@ -18,46 +18,26 @@ fn load_abs_path_rec(
   prelude: &[FileEntry],
   i: &Interner,
   get_source: &impl Fn(Sym) -> IOResult,
-  is_injected: &impl Fn(&[Tok<String>]) -> bool,
+  is_injected_module: &impl Fn(Sym) -> bool,
 ) -> Result<(), Rc<dyn ProjectError>> {
-  let abs_pathv = i.r(abs_path);
+  // # Termination
-  // short-circuit if this import is defined externally or already known
+  //
-  if is_injected(abs_pathv) | table.contains_key(&abs_path) {
+  // Every recursion of this function either
+  // - adds one of the files in the source directory to `table` or
+  // - recursively traverses a directory tree
+  // therefore eventually the function exits, assuming that the directory tree
+  // contains no cycles.
+
+  // Termination: exit if entry already visited
+  if table.contains_key(&abs_path) {
     return Ok(());
   }
+
   // try splitting the path to file, swallowing any IO errors
-  let is_file = |p| (get_source)(p).map(|l| l.is_code()).unwrap_or(false);
+  let is_file = |sym| get_source(sym).map(|l| l.is_code()).unwrap_or(false);
-  let name_split = split_name(abs_pathv, &|p| is_file(i.i(p)));
+  let name_split = split_max_prefix(&i.r(abs_path)[..], &|p| is_file(i.i(p)));
-  let filename = if let Some((f, _)) = name_split {
+  if let Some((filename, _)) = name_split {
-    f
+    // if the filename is valid, load, preparse and record this file
-  } else {
-    // If the path could not be split to file, load it as directory
-    let coll = if let Loaded::Collection(c) = (get_source)(abs_path)? {
-      c
-    }
-    // ^^ raise any IO error that was previously swallowed
-    else {
-      panic!("split_name returned None but the path is a file")
-    };
-    // recurse on all files and folders within
-    for item in coll.iter() {
-      let abs_subpath = abs_pathv
-        .iter()
-        .copied()
-        .chain(iter::once(i.i(item)))
-        .collect::<Vec<_>>();
-      load_abs_path_rec(
-        i.i(&abs_subpath),
-        table,
-        prelude,
-        i,
-        get_source,
-        is_injected,
-      )?
-    }
-    return Ok(());
-  };
-  // otherwise load, preparse and record this file
     let text = load_text(i.i(filename), &get_source, i)?;
     let preparsed = preparse(
       filename.iter().map(|t| i.r(*t)).cloned().collect(),
@@ -65,7 +45,10 @@ fn load_abs_path_rec(
       prelude,
       i,
     )?;
-  table.insert(abs_path, LoadedSource { text, preparsed: preparsed.clone() });
+    table.insert(i.i(filename), LoadedSource {
+      text,
+      preparsed: preparsed.clone(),
+    });
     // recurse on all imported modules
     preparsed.0.visit_all_imports(&mut |modpath, _module, import| {
       let abs_pathv =
@@ -77,23 +60,64 @@ fn load_abs_path_rec(
         prelude,
         i,
         get_source,
-      is_injected,
+        is_injected_module,
       )
     })
+  } else {
+    // If the path is not within a file, load it as directory
+    let coll = match get_source(abs_path) {
+      Ok(Loaded::Collection(coll)) => coll,
+      Ok(Loaded::Code(_)) =>
+        unreachable!("split_name returned None but the path is a file"),
+      Err(e) => {
+        let parent = i.r(abs_path).split_last().expect("import path nonzero").1;
+        // exit without error if it was injected, or raise any IO error that was
+        // previously swallowed
+        return if is_injected_module(i.i(parent)) { Ok(()) } else { Err(e) };
+      },
+    };
+    // recurse on all files and folders within
+    for item in coll.iter() {
+      let abs_subpath = (i.r(abs_path).iter())
+        .copied()
+        .chain(iter::once(i.i(item)))
+        .collect::<Vec<_>>();
+      load_abs_path_rec(
+        i.i(&abs_subpath),
+        table,
+        prelude,
+        i,
+        get_source,
+        is_injected_module,
+      )?
+    }
+    Ok(())
+  }
 }
 
 /// Load and preparse all files reachable from the load targets via
 /// imports that aren't injected.
+///
+/// is_injected_module must return false for injected symbols, but may return
+/// true for parents of injected modules that are not directly part of the
+/// injected data (the ProjectTree doesn't make a distinction between the two)
 pub fn load_source(
   targets: &[Sym],
   prelude: &[FileEntry],
   i: &Interner,
   get_source: &impl Fn(Sym) -> IOResult,
-  is_injected: &impl Fn(&[Tok<String>]) -> bool,
+  is_injected_module: &impl Fn(Sym) -> bool,
 ) -> Result<LoadedSourceTable, Rc<dyn ProjectError>> {
   let mut table = LoadedSourceTable::new();
   for target in targets {
-    load_abs_path_rec(*target, &mut table, prelude, i, get_source, is_injected)?
+    load_abs_path_rec(
+      *target,
+      &mut table,
+      prelude,
+      i,
+      get_source,
+      is_injected_module,
+    )?
   }
   Ok(table)
 }

src/pipeline/split_name.rs

@@ -1,16 +0,0 @@
-use crate::interner::Tok;
-
-#[allow(clippy::type_complexity)]
-// FIXME couldn't find a good factoring
-pub fn split_name<'a>(
-  path: &'a [Tok<String>],
-  is_valid: &impl Fn(&[Tok<String>]) -> bool,
-) -> Option<(&'a [Tok<String>], &'a [Tok<String>])> {
-  for split in (0..=path.len()).rev() {
-    let (filename, subpath) = path.split_at(split);
-    if is_valid(filename) {
-      return Some((filename, subpath));
-    }
-  }
-  None
-}

src/representations/ast.rs

@@ -179,11 +179,8 @@ impl Clause {
     match self {
       Clause::Lambda(arg, body) => {
         arg.visit_names(binds, cb);
-        let new_binds = if let Clause::Name(n) = arg.value {
+        let new_binds =
-          binds.push(n)
+          if let Clause::Name(n) = arg.value { binds.push(n) } else { binds };
-        } else {
-          binds
-        };
         for x in body.iter() {
           x.visit_names(new_binds, cb)
         }
@@ -216,11 +213,7 @@ impl Clause {
             val.unwrap_or_else(|| e.clone())
           })
           .collect();
-        if any_some {
+        if any_some { Some(Clause::S(*c, Rc::new(new_body))) } else { None }
-          Some(Clause::S(*c, Rc::new(new_body)))
-        } else {
-          None
-        }
       },
       Clause::Lambda(arg, body) => {
         let new_arg = arg.map_names(pred);

src/representations/interpreted.rs

@@ -219,3 +219,9 @@ impl<T: Into<Literal>> From<T> for Clause {
     Self::P(Primitive::Literal(value.into()))
   }
 }
+
+impl<T: Into<Clause>> From<T> for ExprInst {
+  fn from(value: T) -> Self {
+    value.into().wrap()
+  }
+}

src/representations/sourcefile.rs

@@ -1,4 +1,6 @@
 //! Building blocks of a source file
+use std::iter;
+
 use itertools::{Either, Itertools};
 
 use crate::ast::{Constant, Rule};
@@ -157,7 +159,9 @@ pub fn absolute_path(
     if tail.is_empty() {
       Ok(new_abs.to_vec())
     } else {
-      absolute_path(new_abs, tail, i)
+      let new_rel =
+        iter::once(i.i("self")).chain(tail.iter().copied()).collect::<Vec<_>>();
+      absolute_path(new_abs, &new_rel, i)
     }
   } else if *head == i.i("self") {
     Ok(abs_location.iter().chain(tail.iter()).copied().collect())

src/representations/tree.rs

@@ -107,23 +107,23 @@ impl<TItem: Clone, TExt: Clone> Module<TItem, TExt> {
   ) -> Result<(), E> {
     self.visit_all_imports_rec(Substack::Bottom, callback)
   }
-}
 
-impl<TItem: Clone, TExt: Clone + Add<Output = TExt>> Add
+  /// Combine two module trees; wherever they conflict, the overlay is
-  for Module<TItem, TExt>
+  /// preferred.
-{
+  pub fn overlay(mut self, overlay: Self) -> Self
-  type Output = Self;
+  where
-
+    TExt: Add<TExt, Output = TExt>,
-  fn add(mut self, rhs: Self) -> Self::Output {
+  {
-    let Module { extra, imports, items } = rhs;
+    let Module { extra, imports, items } = overlay;
+    let mut new_items = HashMap::new();
     for (key, right) in items {
       // if both contain a submodule
       if let Some(left) = self.items.remove(&key) {
         if let ModMember::Sub(rsub) = &right.member {
           if let ModMember::Sub(lsub) = &left.member {
             // merge them with rhs exportedness
-            let new_mod = lsub.as_ref().clone() + rsub.as_ref().clone();
+            let new_mod = lsub.as_ref().clone().overlay(rsub.as_ref().clone());
-            self.items.insert(key, ModEntry {
+            new_items.insert(key, ModEntry {
               exported: right.exported,
               member: ModMember::Sub(Rc::new(new_mod)),
             });
@@ -132,10 +132,14 @@ impl<TItem: Clone, TExt: Clone + Add<Output = TExt>> Add
         }
       }
       // otherwise right shadows left
-      self.items.insert(key, right);
+      new_items.insert(key, right);
     }
+    new_items.extend(self.items.into_iter());
     self.imports.extend(imports.into_iter());
-    self.extra = self.extra + extra;
+    Module {
-    self
+      items: new_items,
+      imports: self.imports,
+      extra: self.extra + extra,
+    }
   }
 }

src/rule/matcher_vectree/build.rs

@@ -56,11 +56,8 @@ fn mk_vec(pattern: &[Expr]) -> VecMatcher {
     pattern.last().map(vec_attrs).is_some(),
     "pattern must end with a vectorial"
   );
-  let (left, (key, prio, nonzero), right) = split_at_max_vec(pattern)
+  let (left, (key, _, nonzero), right) = split_at_max_vec(pattern)
     .expect("pattern must have vectorial placeholders at least at either end");
-  if prio >= 1 {
-    println!("Nondefault priority {} found", prio)
-  }
   let r_sep_size = scal_cnt(right.iter());
   let (r_sep, r_side) = right.split_at(r_sep_size);
   let l_sep_size = scal_cnt(left.iter().rev());

src/rule/repository.rs

@@ -114,29 +114,25 @@ impl<M: Matcher> Repository<M> {
   /// Attempt to run each rule in priority order `limit` times. Returns
   /// the final tree and the number of iterations left to the limit.
   #[allow(unused)]
-  pub fn long_step(
+  pub fn long_step(&self, code: &Expr, mut limit: usize) -> (Expr, usize) {
-    &self,
-    code: &Expr,
-    mut limit: usize,
-  ) -> Result<(Expr, usize), RuleError> {
     if limit == 0 {
-      return Ok((code.clone(), 0));
+      return (code.clone(), 0);
     }
     if let Some(mut processed) = self.step(code) {
       limit -= 1;
       if limit == 0 {
-        return Ok((processed, 0));
+        return (processed, 0);
       }
       while let Some(out) = self.step(&processed) {
         limit -= 1;
         if limit == 0 {
-          return Ok((out, 0));
+          return (out, 0);
         }
         processed = out;
       }
-      Ok((processed, limit))
+      (processed, limit)
     } else {
-      Ok((code.clone(), limit))
+      (code.clone(), limit)
     }
   }
 }

src/stl/arithmetic_error.rs

@@ -0,0 +1,28 @@
+use std::fmt::Display;
+
+use crate::foreign::ExternError;
+
+/// Various errors produced by arithmetic operations
+pub enum ArithmeticError {
+  /// Integer overflow
+  Overflow,
+  /// Float overflow
+  Infinity,
+  /// Division or modulo by zero
+  DivByZero,
+  /// Other, unexpected operation produced NaN
+  NaN,
+}
+
+impl Display for ArithmeticError {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    match self {
+      Self::NaN => write!(f, "Operation resulted in NaN"),
+      Self::Overflow => write!(f, "Integer overflow"),
+      Self::Infinity => write!(f, "Operation resulted in Infinity"),
+      Self::DivByZero => write!(f, "A division by zero was attempted"),
+    }
+  }
+}
+
+impl ExternError for ArithmeticError {}

src/stl/bool.orc

@@ -0,0 +1,4 @@
+export ...$a == ...$b =0x3p36=> (equals (...$a) (...$b))
+export if ...$cond then ...$true else ...$false:1 =0x1p84=> (
+  ifthenelse (...$cond) (...$true) (...$false)
+)

src/stl/bool.rs

@@ -0,0 +1,92 @@
+use std::rc::Rc;
+
+use crate::foreign::Atom;
+use crate::interner::Interner;
+use crate::pipeline::ConstTree;
+use crate::representations::interpreted::{Clause, ExprInst};
+use crate::representations::Primitive;
+use crate::stl::litconv::with_lit;
+use crate::stl::AssertionError;
+use crate::{atomic_inert, define_fn, Literal, PathSet};
+
+/// Booleans exposed to Orchid
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct Boolean(pub bool);
+atomic_inert!(Boolean);
+
+impl From<bool> for Boolean {
+  fn from(value: bool) -> Self {
+    Self(value)
+  }
+}
+
+impl TryFrom<&ExprInst> for Boolean {
+  type Error = ();
+
+  fn try_from(value: &ExprInst) -> Result<Self, Self::Error> {
+    let expr = value.expr();
+    if let Clause::P(Primitive::Atom(Atom(a))) = &expr.clause {
+      if let Some(b) = a.as_any().downcast_ref::<Boolean>() {
+        return Ok(*b);
+      }
+    }
+    Err(())
+  }
+}
+
+define_fn! {expr=x in
+  /// Compares the inner values if
+  ///
+  /// - both values are char,
+  /// - both are string,
+  /// - both are either uint or num
+  Equals {
+    a: Literal as with_lit(x, |l| Ok(l.clone())),
+    b: Literal as with_lit(x, |l| Ok(l.clone()))
+  } => Ok(Boolean::from(match (a, b) {
+    (Literal::Char(c1), Literal::Char(c2)) => c1 == c2,
+    (Literal::Num(n1), Literal::Num(n2)) => n1 == n2,
+    (Literal::Str(s1), Literal::Str(s2)) => s1 == s2,
+    (Literal::Uint(i1), Literal::Uint(i2)) => i1 == i2,
+    (Literal::Num(n1), Literal::Uint(u1)) => *n1 == (*u1 as f64),
+    (Literal::Uint(u1), Literal::Num(n1)) => *n1 == (*u1 as f64),
+    (..) => AssertionError::fail(
+      b.clone().into(),
+      "the expected type"
+    )?,
+  }).to_atom_cls())
+}
+
+// Even though it's a ternary function, IfThenElse is implemented as an unary
+// foreign function, as the rest of the logic can be defined in Orchid.
+define_fn! {
+  /// Takes a boolean and two branches, runs the first if the bool is true, the
+  /// second if it's false.
+  IfThenElse = |x: &ExprInst| x.try_into()
+    .map_err(|_| AssertionError::ext(x.clone(), "a boolean"))
+    .map(|b: Boolean| if b.0 {Clause::Lambda {
+      args: Some(PathSet { steps: Rc::new(vec![]), next: None }),
+      body: Clause::Lambda {
+        args: None,
+        body: Clause::LambdaArg.wrap()
+      }.wrap(),
+    }} else {Clause::Lambda {
+      args: None,
+      body: Clause::Lambda {
+        args: Some(PathSet { steps: Rc::new(vec![]), next: None }),
+        body: Clause::LambdaArg.wrap(),
+      }.wrap(),
+    }})
+}
+
+pub fn bool(i: &Interner) -> ConstTree {
+  ConstTree::tree([(
+    i.i("bool"),
+    ConstTree::tree([
+      (i.i("ifthenelse"), ConstTree::xfn(IfThenElse)),
+      (i.i("equals"), ConstTree::xfn(Equals)),
+      (i.i("true"), ConstTree::atom(Boolean(true))),
+      (i.i("false"), ConstTree::atom(Boolean(false))),
+    ]),
+  )])
+}

src/stl/bool/boolean.rs

@@ -1,29 +0,0 @@
-use crate::atomic_inert;
-use crate::foreign::Atom;
-use crate::representations::interpreted::{Clause, ExprInst};
-use crate::representations::Primitive;
-
-/// Booleans exposed to Orchid
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct Boolean(pub bool);
-atomic_inert!(Boolean);
-
-impl From<bool> for Boolean {
-  fn from(value: bool) -> Self {
-    Self(value)
-  }
-}
-
-impl TryFrom<ExprInst> for Boolean {
-  type Error = ();
-
-  fn try_from(value: ExprInst) -> Result<Self, Self::Error> {
-    let expr = value.expr();
-    if let Clause::P(Primitive::Atom(Atom(a))) = &expr.clause {
-      if let Some(b) = a.as_any().downcast_ref::<Boolean>() {
-        return Ok(*b);
-      }
-    }
-    Err(())
-  }
-}

src/stl/bool/equals.rs

@@ -1,54 +0,0 @@
-use std::fmt::Debug;
-
-use super::super::assertion_error::AssertionError;
-use super::super::litconv::with_lit;
-use super::boolean::Boolean;
-use crate::representations::interpreted::ExprInst;
-use crate::representations::Literal;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-/// Compares the inner values if
-///
-/// - both values are char,
-/// - both are string,
-/// - both are either uint or num
-///
-/// Next state: [Equals1]
-
-#[derive(Clone)]
-pub struct Equals2;
-externfn_impl!(Equals2, |_: &Self, x: ExprInst| Ok(Equals1 { x }));
-
-/// Prev state: [Equals2]; Next state: [Equals0]
-
-#[derive(Debug, Clone)]
-pub struct Equals1 {
-  x: ExprInst,
-}
-atomic_redirect!(Equals1, x);
-atomic_impl!(Equals1);
-externfn_impl!(Equals1, |this: &Self, x: ExprInst| {
-  with_lit(&this.x, |l| Ok(Equals0 { a: l.clone(), x }))
-});
-
-/// Prev state: [Equals1]
-#[derive(Debug, Clone)]
-pub struct Equals0 {
-  a: Literal,
-  x: ExprInst,
-}
-atomic_redirect!(Equals0, x);
-atomic_impl!(Equals0, |Self { a, x }: &Self, _| {
-  let eqls = with_lit(x, |l| {
-    Ok(match (a, l) {
-      (Literal::Char(c1), Literal::Char(c2)) => c1 == c2,
-      (Literal::Num(n1), Literal::Num(n2)) => n1 == n2,
-      (Literal::Str(s1), Literal::Str(s2)) => s1 == s2,
-      (Literal::Uint(i1), Literal::Uint(i2)) => i1 == i2,
-      (Literal::Num(n1), Literal::Uint(u1)) => *n1 == (*u1 as f64),
-      (Literal::Uint(u1), Literal::Num(n1)) => *n1 == (*u1 as f64),
-      (..) => AssertionError::fail(x.clone(), "the expected type")?,
-    })
-  })?;
-  Ok(Boolean::from(eqls).to_atom_cls())
-});

src/stl/bool/ifthenelse.rs

@@ -1,46 +0,0 @@
-use std::fmt::Debug;
-use std::rc::Rc;
-
-use super::super::assertion_error::AssertionError;
-use super::Boolean;
-use crate::representations::interpreted::{Clause, ExprInst};
-use crate::representations::PathSet;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-/// Takes a boolean and two branches, runs the first if the bool is true, the
-/// second if it's false.
-///
-/// Next state: [IfThenElse0]
-#[derive(Clone)]
-pub struct IfThenElse1;
-externfn_impl!(IfThenElse1, |_: &Self, x: ExprInst| Ok(IfThenElse0 { x }));
-
-/// Prev state: [IfThenElse1]
-#[derive(Debug, Clone)]
-pub struct IfThenElse0 {
-  x: ExprInst,
-}
-atomic_redirect!(IfThenElse0, x);
-atomic_impl!(IfThenElse0, |this: &Self, _| {
-  let Boolean(b) = this
-    .x
-    .clone()
-    .try_into()
-    .map_err(|_| AssertionError::ext(this.x.clone(), "a boolean"))?;
-  Ok(if b {
-    Clause::Lambda {
-      args: Some(PathSet { steps: Rc::new(vec![]), next: None }),
-      body: Clause::Lambda { args: None, body: Clause::LambdaArg.wrap() }
-        .wrap(),
-    }
-  } else {
-    Clause::Lambda {
-      args: None,
-      body: Clause::Lambda {
-        args: Some(PathSet { steps: Rc::new(vec![]), next: None }),
-        body: Clause::LambdaArg.wrap(),
-      }
-      .wrap(),
-    }
-  })
-});

src/stl/bool/mod.rs

@@ -1,16 +0,0 @@
-mod boolean;
-mod equals;
-mod ifthenelse;
-pub use boolean::Boolean;
-
-use crate::interner::Interner;
-use crate::pipeline::ConstTree;
-
-pub fn bool(i: &Interner) -> ConstTree {
-  ConstTree::tree([
-    (i.i("ifthenelse"), ConstTree::xfn(ifthenelse::IfThenElse1)),
-    (i.i("equals"), ConstTree::xfn(equals::Equals2)),
-    (i.i("true"), ConstTree::atom(Boolean(true))),
-    (i.i("false"), ConstTree::atom(Boolean(false))),
-  ])
-}

src/stl/conv.rs

@@ -0,0 +1,67 @@
+use chumsky::Parser;
+use ordered_float::NotNan;
+
+use super::litconv::with_lit;
+use super::{ArithmeticError, AssertionError};
+use crate::foreign::ExternError;
+use crate::interner::Interner;
+use crate::parse::{float_parser, int_parser};
+use crate::pipeline::ConstTree;
+use crate::{define_fn, Literal};
+
+define_fn! {
+  /// parse a number. Accepts the same syntax Orchid does.
+  ToFloat = |x| with_lit(x, |l| match l {
+    Literal::Str(s) => float_parser()
+      .parse(s.as_str())
+      .map_err(|_| AssertionError::ext(
+        x.clone(),
+        "cannot be parsed into a float"
+      )),
+    Literal::Num(n) => Ok(*n),
+    Literal::Uint(i) => NotNan::new(*i as f64)
+      .map_err(|_| ArithmeticError::NaN.into_extern()),
+    Literal::Char(char) => char
+      .to_digit(10)
+      .map(|i| NotNan::new(i as f64).expect("u32 to f64 yielded NaN"))
+      .ok_or_else(|| AssertionError::ext(x.clone(), "is not a decimal digit")),
+  }).map(|nn| Literal::Num(nn).into())
+}
+
+define_fn! {
+  /// Parse an unsigned integer. Accepts the same formats Orchid does. If the
+  /// input is a number, floors it.
+  ToUint = |x| with_lit(x, |l| match l {
+    Literal::Str(s) => int_parser()
+      .parse(s.as_str())
+      .map_err(|_| AssertionError::ext(
+        x.clone(),
+        "cannot be parsed into an unsigned int",
+      )),
+    Literal::Num(n) => Ok(n.floor() as u64),
+    Literal::Uint(i) => Ok(*i),
+    Literal::Char(char) => char
+      .to_digit(10)
+      .map(u64::from)
+      .ok_or(AssertionError::ext(x.clone(), "is not a decimal digit")),
+  }).map(|u| Literal::Uint(u).into())
+}
+
+define_fn! {
+  /// Convert a literal to a string using Rust's conversions for floats, chars and
+  /// uints respectively
+  ToString = |x| with_lit(x, |l| Ok(match l {
+    Literal::Char(c) => c.to_string(),
+    Literal::Uint(i) => i.to_string(),
+    Literal::Num(n) => n.to_string(),
+    Literal::Str(s) => s.clone(),
+  })).map(|s| Literal::Str(s).into())
+}
+
+pub fn conv(i: &Interner) -> ConstTree {
+  ConstTree::tree([
+    (i.i("to_float"), ConstTree::xfn(ToFloat)),
+    (i.i("to_uint"), ConstTree::xfn(ToUint)),
+    (i.i("to_string"), ConstTree::xfn(ToString)),
+  ])
+}

src/stl/conv/mod.rs

@@ -1,14 +0,0 @@
-use crate::interner::Interner;
-use crate::pipeline::ConstTree;
-
-mod parse_float;
-mod parse_uint;
-mod to_string;
-
-pub fn conv(i: &Interner) -> ConstTree {
-  ConstTree::tree([
-    (i.i("parse_float"), ConstTree::xfn(parse_float::ParseFloat1)),
-    (i.i("parse_uint"), ConstTree::xfn(parse_uint::ParseUint1)),
-    (i.i("to_string"), ConstTree::xfn(to_string::ToString1)),
-  ])
-}

src/stl/conv/parse_float.rs

@@ -1,43 +0,0 @@
-use std::fmt::Debug;
-
-use chumsky::Parser;
-
-use super::super::assertion_error::AssertionError;
-use super::super::litconv::with_lit;
-use crate::parse::float_parser;
-use crate::representations::interpreted::ExprInst;
-use crate::representations::Literal;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-/// parse a number. Accepts the same syntax Orchid does
-///
-/// Next state: [ParseFloat0]
-#[derive(Clone)]
-pub struct ParseFloat1;
-externfn_impl!(ParseFloat1, |_: &Self, x: ExprInst| Ok(ParseFloat0 { x }));
-
-/// Prev state: [ParseFloat1]
-#[derive(Debug, Clone)]
-pub struct ParseFloat0 {
-  x: ExprInst,
-}
-atomic_redirect!(ParseFloat0, x);
-atomic_impl!(ParseFloat0, |Self { x }: &Self, _| {
-  let number = with_lit(x, |l| {
-    Ok(match l {
-      Literal::Str(s) => {
-        let parser = float_parser();
-        parser.parse(s.as_str()).map_err(|_| {
-          AssertionError::ext(x.clone(), "cannot be parsed into a float")
-        })?
-      },
-      Literal::Num(n) => *n,
-      Literal::Uint(i) => (*i as u32).into(),
-      Literal::Char(char) => char
-        .to_digit(10)
-        .ok_or(AssertionError::ext(x.clone(), "is not a decimal digit"))?
-        .into(),
-    })
-  })?;
-  Ok(number.into())
-});

src/stl/conv/parse_uint.rs

@@ -1,47 +0,0 @@
-use std::fmt::Debug;
-
-use chumsky::Parser;
-
-use super::super::assertion_error::AssertionError;
-use super::super::litconv::with_lit;
-use crate::parse::int_parser;
-use crate::representations::interpreted::ExprInst;
-use crate::representations::Literal;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-/// Parse an unsigned integer. Accepts the same formats Orchid does. If the
-/// input is a number, floors it.
-///
-/// Next state: [ParseUint0]
-#[derive(Clone)]
-pub struct ParseUint1;
-externfn_impl!(ParseUint1, |_: &Self, x: ExprInst| Ok(ParseUint0 { x }));
-
-/// Prev state: [ParseUint1]
-#[derive(Debug, Clone)]
-pub struct ParseUint0 {
-  x: ExprInst,
-}
-atomic_redirect!(ParseUint0, x);
-atomic_impl!(ParseUint0, |Self { x }: &Self, _| {
-  let uint = with_lit(x, |l| {
-    Ok(match l {
-      Literal::Str(s) => {
-        let parser = int_parser();
-        parser.parse(s.as_str()).map_err(|_| {
-          AssertionError::ext(
-            x.clone(),
-            "cannot be parsed into an unsigned int",
-          )
-        })?
-      },
-      Literal::Num(n) => n.floor() as u64,
-      Literal::Uint(i) => *i,
-      Literal::Char(char) => char
-        .to_digit(10)
-        .ok_or(AssertionError::ext(x.clone(), "is not a decimal digit"))?
-        .into(),
-    })
-  })?;
-  Ok(uint.into())
-});

src/stl/conv/to_string.rs

@@ -1,32 +0,0 @@
-use std::fmt::Debug;
-
-use super::super::litconv::with_lit;
-use crate::representations::interpreted::ExprInst;
-use crate::representations::Literal;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-/// Convert a literal to a string using Rust's conversions for floats, chars and
-/// uints respectively
-///
-/// Next state: [ToString0]
-#[derive(Clone)]
-pub struct ToString1;
-externfn_impl!(ToString1, |_: &Self, x: ExprInst| Ok(ToString0 { x }));
-
-/// Prev state: [ToString1]
-#[derive(Debug, Clone)]
-pub struct ToString0 {
-  x: ExprInst,
-}
-atomic_redirect!(ToString0, x);
-atomic_impl!(ToString0, |Self { x }: &Self, _| {
-  let string = with_lit(x, |l| {
-    Ok(match l {
-      Literal::Char(c) => c.to_string(),
-      Literal::Uint(i) => i.to_string(),
-      Literal::Num(n) => n.to_string(),
-      Literal::Str(s) => s.clone(),
-    })
-  })?;
-  Ok(string.into())
-});

src/stl/cpsio/debug.rs

@@ -1,32 +0,0 @@
-use std::fmt::Debug;
-
-use crate::foreign::{Atomic, AtomicReturn};
-use crate::interner::InternedDisplay;
-use crate::interpreter::Context;
-use crate::representations::interpreted::ExprInst;
-use crate::{atomic_defaults, externfn_impl};
-
-/// Print and return whatever expression is in the argument without normalizing
-/// it.
-///
-/// Next state: [Debug1]
-#[derive(Clone)]
-pub struct Debug2;
-externfn_impl!(Debug2, |_: &Self, x: ExprInst| Ok(Debug1 { x }));
-
-/// Prev state: [Debug2]
-#[derive(Debug, Clone)]
-pub struct Debug1 {
-  x: ExprInst,
-}
-impl Atomic for Debug1 {
-  atomic_defaults!();
-  fn run(&self, ctx: Context) -> crate::foreign::AtomicResult {
-    println!("{}", self.x.bundle(ctx.interner));
-    Ok(AtomicReturn {
-      clause: self.x.expr().clause.clone(),
-      gas: ctx.gas.map(|g| g - 1),
-      inert: false,
-    })
-  }
-}

src/stl/cpsio/mod.rs

@@ -1,19 +0,0 @@
-use crate::interner::Interner;
-use crate::pipeline::ConstTree;
-
-mod debug;
-mod io;
-mod panic;
-mod print;
-mod readline;
-
-pub use io::{handle, IO};
-
-pub fn cpsio(i: &Interner) -> ConstTree {
-  ConstTree::tree([
-    (i.i("print"), ConstTree::xfn(print::Print2)),
-    (i.i("readline"), ConstTree::xfn(readline::Readln2)),
-    (i.i("debug"), ConstTree::xfn(debug::Debug2)),
-    (i.i("panic"), ConstTree::xfn(panic::Panic1)),
-  ])
-}

src/stl/cpsio/panic.rs

@@ -1,35 +0,0 @@
-use std::fmt::Display;
-
-use super::super::litconv::with_str;
-use crate::foreign::ExternError;
-use crate::representations::interpreted::ExprInst;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-/// Takes a message, returns an [ExternError] unconditionally.
-///
-/// Next state: [Panic0]
-#[derive(Clone)]
-pub struct Panic1;
-externfn_impl!(Panic1, |_: &Self, x: ExprInst| Ok(Panic0 { x }));
-
-/// Prev state: [Panic1]
-#[derive(Debug, Clone)]
-pub struct Panic0 {
-  x: ExprInst,
-}
-atomic_redirect!(Panic0, x);
-atomic_impl!(Panic0, |Self { x }: &Self, _| {
-  with_str(x, |s| Err(OrchidPanic(s.clone()).into_extern()))
-});
-
-/// An unrecoverable error in Orchid land. Of course, because Orchid is lazy, it
-/// only applies to the expressions that use the one that generated it.
-pub struct OrchidPanic(String);
-
-impl Display for OrchidPanic {
-  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-    write!(f, "Orchid code panicked: {}", self.0)
-  }
-}
-
-impl ExternError for OrchidPanic {}

src/stl/cpsio/print.rs

@@ -1,40 +0,0 @@
-use std::fmt::Debug;
-
-use super::super::litconv::with_str;
-use super::io::IO;
-use crate::foreign::{Atomic, AtomicResult, AtomicReturn};
-use crate::interpreter::Context;
-use crate::representations::interpreted::ExprInst;
-use crate::{atomic_defaults, atomic_impl, atomic_redirect, externfn_impl};
-
-/// Wrap a string and the continuation into an [IO] event to be evaluated by the
-/// embedder.
-///
-/// Next state: [Print1]
-#[derive(Clone)]
-pub struct Print2;
-externfn_impl!(Print2, |_: &Self, x: ExprInst| Ok(Print1 { x }));
-
-/// Prev state: [Print2]; Next state: [Print0]
-#[derive(Debug, Clone)]
-pub struct Print1 {
-  x: ExprInst,
-}
-atomic_redirect!(Print1, x);
-atomic_impl!(Print1);
-externfn_impl!(Print1, |this: &Self, x: ExprInst| {
-  with_str(&this.x, |s| Ok(Print0 { s: s.clone(), x }))
-});
-
-/// Prev state: [Print1]
-#[derive(Debug, Clone)]
-pub struct Print0 {
-  s: String,
-  x: ExprInst,
-}
-impl Atomic for Print0 {
-  atomic_defaults!();
-  fn run(&self, ctx: Context) -> AtomicResult {
-    Ok(AtomicReturn::from_data(IO::Print(self.s.clone(), self.x.clone()), ctx))
-  }
-}

src/stl/cpsio/readline.rs

@@ -1,27 +0,0 @@
-use std::fmt::Debug;
-
-use super::io::IO;
-use crate::foreign::{Atomic, AtomicResult, AtomicReturn};
-use crate::interpreter::Context;
-use crate::representations::interpreted::ExprInst;
-use crate::{atomic_defaults, externfn_impl};
-
-/// Create an [IO] event that reads a line form standard input and calls the
-/// continuation with it.
-///
-/// Next state: [Readln1]
-#[derive(Clone)]
-pub struct Readln2;
-externfn_impl!(Readln2, |_: &Self, x: ExprInst| Ok(Readln1 { x }));
-
-/// Prev state: [Readln2]
-#[derive(Debug, Clone)]
-pub struct Readln1 {
-  x: ExprInst,
-}
-impl Atomic for Readln1 {
-  atomic_defaults!();
-  fn run(&self, ctx: Context) -> AtomicResult {
-    Ok(AtomicReturn::from_data(IO::Readline(self.x.clone()), ctx))
-  }
-}

src/stl/fn.orc

@@ -8,7 +8,7 @@ export loop $r on (..$parameters) with ...$tail =0x5p129=> Y (\$r.
 bind_names ($name ..$rest) $payload =0x1p250=> \$name. bind_names (..$rest) $payload
 bind_names () (...$payload) =0x1p250=> ...$payload
 
-export ...$prefix $ ...$suffix:1 =0x1p39=> ...$prefix (...$suffix)
+export ...$prefix $ ...$suffix:1 =0x1p38=> ...$prefix (...$suffix)
 export ...$prefix |> $fn ..$suffix:1 =0x2p32=> $fn (...$prefix) ..$suffix
 
 export (...$argv) => ...$body =0x2p129=> (bind_names (...$argv) (...$body))

src/stl/io/inspect.rs

@@ -0,0 +1,29 @@
+use std::fmt::Debug;
+
+use crate::foreign::{Atomic, AtomicReturn};
+use crate::interner::InternedDisplay;
+use crate::interpreter::Context;
+use crate::representations::interpreted::ExprInst;
+use crate::{atomic_defaults, write_fn_step};
+
+write_fn_step! {
+  /// Print and return whatever expression is in the argument without
+  /// normalizing it.
+  pub Inspect > Inspect1
+}
+
+#[derive(Debug, Clone)]
+struct Inspect1 {
+  expr_inst: ExprInst,
+}
+impl Atomic for Inspect1 {
+  atomic_defaults!();
+  fn run(&self, ctx: Context) -> crate::foreign::AtomicResult {
+    println!("{}", self.expr_inst.bundle(ctx.interner));
+    Ok(AtomicReturn {
+      clause: self.expr_inst.expr().clause.clone(),
+      gas: ctx.gas.map(|g| g - 1),
+      inert: false,
+    })
+  }
+}

src/stl/io/mod.rs

@@ -0,0 +1,30 @@
+use crate::interner::Interner;
+use crate::pipeline::ConstTree;
+
+mod command;
+mod inspect;
+mod panic;
+mod print;
+mod readline;
+
+pub use command::{handle, IO};
+
+pub fn io(i: &Interner, allow_impure: bool) -> ConstTree {
+  let pure = ConstTree::tree([(
+    i.i("io"),
+    ConstTree::tree([
+      (i.i("print"), ConstTree::xfn(print::Print)),
+      (i.i("readline"), ConstTree::xfn(readline::ReadLn)),
+      (i.i("panic"), ConstTree::xfn(panic::Panic)),
+    ]),
+  )]);
+  if !allow_impure {
+    pure
+  } else {
+    pure
+      + ConstTree::tree([(
+        i.i("io"),
+        ConstTree::tree([(i.i("debug"), ConstTree::xfn(inspect::Inspect))]),
+      )])
+  }
+}

src/stl/io/panic.rs

@@ -0,0 +1,21 @@
+use std::fmt::Display;
+
+use super::super::litconv::with_str;
+use crate::define_fn;
+use crate::foreign::ExternError;
+
+define_fn! {
+  /// Takes a message, returns an [ExternError] unconditionally.
+  pub Panic = |x| with_str(x, |s| Err(OrchidPanic(s.clone()).into_extern()))
+}
+/// An unrecoverable error in Orchid land. Because Orchid is lazy, this only
+/// invalidates expressions that reference the one that generated it.
+pub struct OrchidPanic(String);
+
+impl Display for OrchidPanic {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    write!(f, "Orchid code panicked: {}", self.0)
+  }
+}
+
+impl ExternError for OrchidPanic {}

src/stl/io/print.rs

@@ -0,0 +1,31 @@
+use std::fmt::Debug;
+
+use super::super::litconv::with_str;
+use super::command::IO;
+use crate::foreign::{Atomic, AtomicResult, AtomicReturn};
+use crate::interpreter::Context;
+use crate::representations::interpreted::ExprInst;
+use crate::{atomic_defaults, write_fn_step};
+
+write_fn_step! {
+  /// Wrap a string and the continuation into an [IO] event to be evaluated by
+  /// the embedder.
+  pub Print > Print1
+}
+write_fn_step! {
+  Print1 {}
+  Print0 where message = x => with_str(x, |s| Ok(s.clone()));
+}
+
+#[derive(Debug, Clone)]
+struct Print0 {
+  message: String,
+  expr_inst: ExprInst,
+}
+impl Atomic for Print0 {
+  atomic_defaults!();
+  fn run(&self, ctx: Context) -> AtomicResult {
+    let command = IO::Print(self.message.clone(), self.expr_inst.clone());
+    Ok(AtomicReturn::from_data(command, ctx))
+  }
+}

src/stl/io/readline.rs

@@ -0,0 +1,25 @@
+use std::fmt::Debug;
+
+use super::command::IO;
+use crate::foreign::{Atomic, AtomicResult, AtomicReturn};
+use crate::interpreter::Context;
+use crate::representations::interpreted::ExprInst;
+use crate::{atomic_defaults, write_fn_step};
+
+write_fn_step! {
+  /// Create an [IO] event that reads a line form standard input and calls the
+  /// continuation with it.
+  pub ReadLn > ReadLn1
+}
+
+#[derive(Debug, Clone)]
+struct ReadLn1 {
+  expr_inst: ExprInst,
+}
+impl Atomic for ReadLn1 {
+  atomic_defaults!();
+  fn run(&self, ctx: Context) -> AtomicResult {
+    let command = IO::Readline(self.expr_inst.clone());
+    Ok(AtomicReturn::from_data(command, ctx))
+  }
+}

src/stl/known.orc

@@ -0,0 +1 @@
+export ::(,)

src/stl/list.orc

@@ -1,5 +1,4 @@
-import option
+import super::(option, fn::*, bool::*, known::*, num::*,)
-import super::fn::*
 
 pair := \a.\b. \f. f a b
 

src/stl/map.orc

@@ -1,8 +1,5 @@
-import list
+import super::(bool::*, fn::*, known::*, list, option, proc::*)
-import option
+import std::io::panic
-import fn::*
-import std::to_string
-import std::debug
 
 -- utilities for using lists as pairs
 

src/stl/mk_stl.rs

@@ -1,13 +1,68 @@
+use hashbrown::HashMap;
+use rust_embed::RustEmbed;
+
 use super::bool::bool;
 use super::conv::conv;
-use super::cpsio::cpsio;
+use super::io::io;
 use super::num::num;
 use super::str::str;
-use crate::interner::Interner;
+use crate::interner::{Interner, Sym};
-use crate::pipeline::ConstTree;
+use crate::pipeline::file_loader::mk_embed_cache;
+use crate::pipeline::{from_const_tree, parse_layer, ProjectTree};
+use crate::sourcefile::{FileEntry, Import};
+
+/// Feature flags for the STL.
+#[derive(Default)]
+pub struct StlOptions {
+  /// Whether impure functions (such as io::debug) are allowed. An embedder
+  /// would typically disable this flag
+  pub impure: bool,
+}
+
+#[derive(RustEmbed)]
+#[folder = "src/stl"]
+#[prefix = "std/"]
+#[include = "*.orc"]
+struct StlEmbed;
+
+// TODO: fix all orc modules to not rely on prelude
 
 /// Build the standard library used by the interpreter by combining the other
 /// libraries
-pub fn mk_stl(i: &Interner) -> ConstTree {
+pub fn mk_stl(i: &Interner, options: StlOptions) -> ProjectTree {
-  cpsio(i) + conv(i) + bool(i) + str(i) + num(i)
+  let const_tree = from_const_tree(
+    HashMap::from([(
+      i.i("std"),
+      io(i, options.impure) + conv(i) + bool(i) + str(i) + num(i),
+    )]),
+    &[i.i("std")],
+    i,
+  );
+  let ld_cache = mk_embed_cache::<StlEmbed>(".orc", i);
+  parse_layer(
+    &StlEmbed::iter()
+      .map(|path| -> Sym {
+        let segtoks = path
+          .strip_suffix(".orc")
+          .expect("the embed is filtered for suffix")
+          .split('/')
+          .map(|segment| i.i(segment))
+          .collect::<Vec<_>>();
+        i.i(&segtoks[..])
+      })
+      .collect::<Vec<_>>()[..],
+    &|p| ld_cache.find(&p),
+    &const_tree,
+    &[],
+    i,
+  )
+  .expect("Parse error in STL")
+}
+
+/// Generate prelude lines to be injected to every module compiled with the STL
+pub fn mk_prelude(i: &Interner) -> Vec<FileEntry> {
+  vec![FileEntry::Import(vec![Import {
+    path: i.i(&[i.i("std"), i.i("prelude")][..]),
+    name: None,
+  }])]
 }

src/stl/mod.rs

@@ -1,17 +1,19 @@
 //! Constants exposed to usercode by the interpreter
+mod arithmetic_error;
 mod assertion_error;
 mod bool;
 mod conv;
-mod cpsio;
+mod io;
 pub mod litconv;
 mod mk_stl;
 mod num;
 mod runtime_error;
 mod str;
 
+pub use arithmetic_error::ArithmeticError;
 pub use assertion_error::AssertionError;
-pub use cpsio::{handle as handleIO, IO};
+pub use io::{handle as handleIO, IO};
-pub use mk_stl::mk_stl;
+pub use mk_stl::{mk_prelude, mk_stl, StlOptions};
 pub use runtime_error::RuntimeError;
 
 pub use self::bool::Boolean;

src/stl/num.orc

@@ -0,0 +1,5 @@
+export ...$a + ...$b =0x2p36=> (add (...$a) (...$b))
+export ...$a - ...$b:1 =0x2p36=> (subtract (...$a) (...$b))
+export ...$a * ...$b =0x1p36=> (multiply (...$a) (...$b))
+export ...$a % ...$b:1 =0x1p36=> (remainder (...$a) (...$b))
+export ...$a / ...$b:1 =0x1p36=> (divide (...$a) (...$b))

src/stl/num.rs

@@ -0,0 +1,149 @@
+use std::rc::Rc;
+
+use ordered_float::NotNan;
+
+use super::litconv::with_lit;
+use super::{ArithmeticError, AssertionError};
+use crate::define_fn;
+use crate::foreign::ExternError;
+use crate::interner::Interner;
+use crate::pipeline::ConstTree;
+use crate::representations::interpreted::{Clause, ExprInst};
+use crate::representations::{Literal, Primitive};
+
+// region:  Numeric, type to handle floats and uints together
+
+/// A number, either floating point or unsigned int, visible to Orchid.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum Numeric {
+  /// A nonnegative integer such as a size, index or count
+  Uint(u64),
+  /// A float other than NaN. Orchid has no silent errors
+  Num(NotNan<f64>),
+}
+
+impl Numeric {
+  fn as_f64(&self) -> f64 {
+    match self {
+      Numeric::Num(n) => **n,
+      Numeric::Uint(i) => *i as f64,
+    }
+  }
+
+  /// Wrap a f64 in a Numeric
+  fn num(value: f64) -> Result<Self, Rc<dyn ExternError>> {
+    if value.is_finite() {
+      NotNan::new(value)
+        .map(Self::Num)
+        .map_err(|_| ArithmeticError::NaN.into_extern())
+    } else {
+      Err(ArithmeticError::Infinity.into_extern())
+    }
+  }
+}
+
+impl TryFrom<&ExprInst> for Numeric {
+  type Error = Rc<dyn ExternError>;
+  fn try_from(value: &ExprInst) -> Result<Self, Self::Error> {
+    with_lit(value, |l| match l {
+      Literal::Uint(i) => Ok(Numeric::Uint(*i)),
+      Literal::Num(n) => Ok(Numeric::Num(*n)),
+      _ => AssertionError::fail(value.clone(), "an integer or number")?,
+    })
+  }
+}
+
+impl From<Numeric> for Clause {
+  fn from(value: Numeric) -> Self {
+    Clause::P(Primitive::Literal(match value {
+      Numeric::Uint(i) => Literal::Uint(i),
+      Numeric::Num(n) => Literal::Num(n),
+    }))
+  }
+}
+
+// endregion
+
+// region: operations
+
+define_fn! {
+  /// Add two numbers. If they're both uint, the output is uint. If either is
+  /// number, the output is number.
+  Add { a: Numeric, b: Numeric } => match (a, b) {
+    (Numeric::Uint(a), Numeric::Uint(b)) => {
+      a.checked_add(*b)
+        .map(Numeric::Uint)
+        .ok_or_else(|| ArithmeticError::Overflow.into_extern())
+    }
+    (Numeric::Num(a), Numeric::Num(b)) => Numeric::num(*(a + b)),
+    (Numeric::Num(a), Numeric::Uint(b)) | (Numeric::Uint(b), Numeric::Num(a))
+    => Numeric::num(a.into_inner() + *b as f64),
+  }.map(Numeric::into)
+}
+
+define_fn! {
+  /// Subtract a number from another. Always returns Number.
+  Subtract { a: Numeric, b: Numeric } => match (a, b) {
+    (Numeric::Uint(a), Numeric::Uint(b)) => Numeric::num(*a as f64 - *b as f64),
+    (Numeric::Num(a), Numeric::Num(b)) => Numeric::num(*(a - b)),
+    (Numeric::Num(a), Numeric::Uint(b)) => Numeric::num(**a - *b as f64),
+    (Numeric::Uint(a), Numeric::Num(b)) => Numeric::num(*a as f64 - **b),
+  }.map(Numeric::into)
+}
+
+define_fn! {
+  /// Multiply two numbers. If they're both uint, the output is uint. If either
+  /// is number, the output is number.
+  Multiply { a: Numeric, b: Numeric } => match (a, b) {
+    (Numeric::Uint(a), Numeric::Uint(b)) => {
+      a.checked_mul(*b)
+        .map(Numeric::Uint)
+        .ok_or_else(|| ArithmeticError::Overflow.into_extern())
+    }
+    (Numeric::Num(a), Numeric::Num(b)) => Numeric::num(*(a * b)),
+    (Numeric::Uint(a), Numeric::Num(b)) | (Numeric::Num(b), Numeric::Uint(a))
+      => Numeric::num(*a as f64 * **b),
+  }.map(Numeric::into)
+}
+
+define_fn! {
+  /// Divide a number by another. Always returns Number.
+  Divide { a: Numeric, b: Numeric } => {
+    let a: f64 = a.as_f64();
+    let b: f64 = b.as_f64();
+    if b == 0.0 {
+      return Err(ArithmeticError::DivByZero.into_extern())
+    }
+    Numeric::num(a / b).map(Numeric::into)
+  }
+}
+
+define_fn! {
+  /// Take the remainder of two numbers.  If they're both uint, the output is
+  /// uint. If either is number, the output is number.
+  Remainder { a: Numeric, b: Numeric } => match (a, b) {
+    (Numeric::Uint(a), Numeric::Uint(b)) => {
+      a.checked_rem(*b)
+        .map(Numeric::Uint)
+        .ok_or_else(|| ArithmeticError::DivByZero.into_extern())
+    }
+    (Numeric::Num(a), Numeric::Num(b)) => Numeric::num(*(a % b)),
+    (Numeric::Uint(a), Numeric::Num(b)) => Numeric::num(*a as f64 % **b),
+    (Numeric::Num(a), Numeric::Uint(b)) => Numeric::num(**a % *b as f64),
+  }.map(Numeric::into)
+}
+
+// endregion
+
+pub fn num(i: &Interner) -> ConstTree {
+  ConstTree::tree([(
+    i.i("num"),
+    ConstTree::tree([
+      (i.i("add"), ConstTree::xfn(Add)),
+      (i.i("subtract"), ConstTree::xfn(Subtract)),
+      (i.i("multiply"), ConstTree::xfn(Multiply)),
+      (i.i("divide"), ConstTree::xfn(Divide)),
+      (i.i("remainder"), ConstTree::xfn(Remainder)),
+    ]),
+  )])
+}

src/stl/num/mod.rs

@@ -1,16 +0,0 @@
-mod numeric;
-pub mod operators;
-pub use numeric::Numeric;
-
-use crate::interner::Interner;
-use crate::pipeline::ConstTree;
-
-pub fn num(i: &Interner) -> ConstTree {
-  ConstTree::tree([
-    (i.i("add"), ConstTree::xfn(operators::add::Add2)),
-    (i.i("subtract"), ConstTree::xfn(operators::subtract::Subtract2)),
-    (i.i("multiply"), ConstTree::xfn(operators::multiply::Multiply2)),
-    (i.i("divide"), ConstTree::xfn(operators::divide::Divide2)),
-    (i.i("remainder"), ConstTree::xfn(operators::remainder::Remainder2)),
-  ])
-}

src/stl/num/numeric.rs

@@ -1,135 +0,0 @@
-use std::ops::{Add, Div, Mul, Rem, Sub};
-use std::rc::Rc;
-
-use ordered_float::NotNan;
-
-use super::super::assertion_error::AssertionError;
-use super::super::litconv::with_lit;
-use crate::foreign::ExternError;
-use crate::representations::interpreted::{Clause, ExprInst};
-use crate::representations::{Literal, Primitive};
-
-/// A number, either floating point or unsigned int, visible to Orchid.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub enum Numeric {
-  /// A nonnegative integer such as a size, index or count
-  Uint(u64),
-  /// A float other than NaN. Orchid has no silent errors
-  Num(NotNan<f64>),
-}
-
-impl Numeric {
-  /// Wrap a f64 in a Numeric
-  ///
-  /// # Panics
-  ///
-  /// if the value is NaN or Infinity.try_into()
-  fn num<T: Into<f64>>(value: T) -> Self {
-    let f = value.into();
-    assert!(f.is_finite(), "unrepresentable number");
-    NotNan::try_from(f).map(Self::Num).expect("not a number")
-  }
-}
-
-impl Add for Numeric {
-  type Output = Numeric;
-
-  fn add(self, rhs: Self) -> Self::Output {
-    match (self, rhs) {
-      (Numeric::Uint(a), Numeric::Uint(b)) => Numeric::Uint(a + b),
-      (Numeric::Num(a), Numeric::Num(b)) => Numeric::num(a + b),
-      (Numeric::Uint(a), Numeric::Num(b))
-      | (Numeric::Num(b), Numeric::Uint(a)) =>
-        Numeric::num::<f64>(a as f64 + *b),
-    }
-  }
-}
-
-impl Sub for Numeric {
-  type Output = Numeric;
-
-  fn sub(self, rhs: Self) -> Self::Output {
-    match (self, rhs) {
-      (Numeric::Uint(a), Numeric::Uint(b)) if b <= a => Numeric::Uint(a - b),
-      (Numeric::Uint(a), Numeric::Uint(b)) => Numeric::num(a as f64 - b as f64),
-      (Numeric::Num(a), Numeric::Num(b)) => Numeric::num(a - b),
-      (Numeric::Uint(a), Numeric::Num(b)) => Numeric::num(a as f64 - *b),
-      (Numeric::Num(a), Numeric::Uint(b)) => Numeric::num(*a - b as f64),
-    }
-  }
-}
-
-impl Mul for Numeric {
-  type Output = Numeric;
-
-  fn mul(self, rhs: Self) -> Self::Output {
-    match (self, rhs) {
-      (Numeric::Uint(a), Numeric::Uint(b)) => Numeric::Uint(a * b),
-      (Numeric::Num(a), Numeric::Num(b)) => Numeric::num(a * b),
-      (Numeric::Uint(a), Numeric::Num(b))
-      | (Numeric::Num(b), Numeric::Uint(a)) =>
-        Numeric::Num(NotNan::new(a as f64).unwrap() * b),
-    }
-  }
-}
-
-impl Div for Numeric {
-  type Output = Numeric;
-
-  fn div(self, rhs: Self) -> Self::Output {
-    let a: f64 = self.into();
-    let b: f64 = rhs.into();
-    Numeric::num(a / b)
-  }
-}
-
-impl Rem for Numeric {
-  type Output = Numeric;
-
-  fn rem(self, rhs: Self) -> Self::Output {
-    match (self, rhs) {
-      (Numeric::Uint(a), Numeric::Uint(b)) => Numeric::Uint(a % b),
-      (Numeric::Num(a), Numeric::Num(b)) => Numeric::num(a % b),
-      (Numeric::Uint(a), Numeric::Num(b)) => Numeric::num(a as f64 % *b),
-      (Numeric::Num(a), Numeric::Uint(b)) => Numeric::num(*a % b as f64),
-    }
-  }
-}
-
-impl TryFrom<ExprInst> for Numeric {
-  type Error = Rc<dyn ExternError>;
-  fn try_from(value: ExprInst) -> Result<Self, Self::Error> {
-    with_lit(&value.clone(), |l| match l {
-      Literal::Uint(i) => Ok(Numeric::Uint(*i)),
-      Literal::Num(n) => Ok(Numeric::Num(*n)),
-      _ => AssertionError::fail(value, "an integer or number")?,
-    })
-  }
-}
-
-impl From<Numeric> for Clause {
-  fn from(value: Numeric) -> Self {
-    Clause::P(Primitive::Literal(match value {
-      Numeric::Uint(i) => Literal::Uint(i),
-      Numeric::Num(n) => Literal::Num(n),
-    }))
-  }
-}
-
-impl From<Numeric> for String {
-  fn from(value: Numeric) -> Self {
-    match value {
-      Numeric::Uint(i) => i.to_string(),
-      Numeric::Num(n) => n.to_string(),
-    }
-  }
-}
-
-impl From<Numeric> for f64 {
-  fn from(val: Numeric) -> Self {
-    match val {
-      Numeric::Num(n) => *n,
-      Numeric::Uint(i) => i as f64,
-    }
-  }
-}

src/stl/num/operators/add.rs

@@ -1,31 +0,0 @@
-use std::fmt::Debug;
-
-use super::super::Numeric;
-use crate::representations::interpreted::ExprInst;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-#[derive(Clone)]
-pub struct Add2;
-externfn_impl!(Add2, |_: &Self, x: ExprInst| Ok(Add1 { x }));
-
-#[derive(Debug, Clone)]
-pub struct Add1 {
-  x: ExprInst,
-}
-atomic_redirect!(Add1, x);
-atomic_impl!(Add1);
-externfn_impl!(Add1, |this: &Self, x: ExprInst| {
-  let a: Numeric = this.x.clone().try_into()?;
-  Ok(Add0 { a, x })
-});
-
-#[derive(Debug, Clone)]
-pub struct Add0 {
-  a: Numeric,
-  x: ExprInst,
-}
-atomic_redirect!(Add0, x);
-atomic_impl!(Add0, |Self { a, x }: &Self, _| {
-  let b: Numeric = x.clone().try_into()?;
-  Ok((*a + b).into())
-});

src/stl/num/operators/divide.rs

@@ -1,37 +0,0 @@
-use std::fmt::Debug;
-
-use super::super::Numeric;
-use crate::representations::interpreted::ExprInst;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-/// Divides two numbers
-///
-/// Next state: [Divide1]
-
-#[derive(Clone)]
-pub struct Divide2;
-externfn_impl!(Divide2, |_: &Self, x: ExprInst| Ok(Divide1 { x }));
-
-/// Prev state: [Divide2]; Next state: [Divide0]
-#[derive(Debug, Clone)]
-pub struct Divide1 {
-  x: ExprInst,
-}
-atomic_redirect!(Divide1, x);
-atomic_impl!(Divide1);
-externfn_impl!(Divide1, |this: &Self, x: ExprInst| {
-  let a: Numeric = this.x.clone().try_into()?;
-  Ok(Divide0 { a, x })
-});
-
-/// Prev state: [Divide1]
-#[derive(Debug, Clone)]
-pub struct Divide0 {
-  a: Numeric,
-  x: ExprInst,
-}
-atomic_redirect!(Divide0, x);
-atomic_impl!(Divide0, |Self { a, x }: &Self, _| {
-  let b: Numeric = x.clone().try_into()?;
-  Ok((*a / b).into())
-});

src/stl/num/operators/mod.rs

@@ -1,5 +0,0 @@
-pub mod add;
-pub mod divide;
-pub mod multiply;
-pub mod remainder;
-pub mod subtract;

src/stl/num/operators/multiply.rs

@@ -1,36 +0,0 @@
-use std::fmt::Debug;
-
-use super::super::Numeric;
-use crate::representations::interpreted::ExprInst;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-/// Multiplies two numbers
-///
-/// Next state: [Multiply1]
-#[derive(Clone)]
-pub struct Multiply2;
-externfn_impl!(Multiply2, |_: &Self, x: ExprInst| Ok(Multiply1 { x }));
-
-/// Prev state: [Multiply2]; Next state: [Multiply0]
-#[derive(Debug, Clone)]
-pub struct Multiply1 {
-  x: ExprInst,
-}
-atomic_redirect!(Multiply1, x);
-atomic_impl!(Multiply1);
-externfn_impl!(Multiply1, |this: &Self, x: ExprInst| {
-  let a: Numeric = this.x.clone().try_into()?;
-  Ok(Multiply0 { a, x })
-});
-
-/// Prev state: [Multiply1]
-#[derive(Debug, Clone)]
-pub struct Multiply0 {
-  a: Numeric,
-  x: ExprInst,
-}
-atomic_redirect!(Multiply0, x);
-atomic_impl!(Multiply0, |Self { a, x }: &Self, _| {
-  let b: Numeric = x.clone().try_into()?;
-  Ok((*a * b).into())
-});

src/stl/num/operators/remainder.rs

@@ -1,36 +0,0 @@
-use std::fmt::Debug;
-
-use super::super::Numeric;
-use crate::representations::interpreted::ExprInst;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-/// Takes the modulus of two numbers.
-///
-/// Next state: [Remainder1]
-#[derive(Clone)]
-pub struct Remainder2;
-externfn_impl!(Remainder2, |_: &Self, x: ExprInst| Ok(Remainder1 { x }));
-
-/// Prev state: [Remainder2]; Next state: [Remainder0]
-#[derive(Debug, Clone)]
-pub struct Remainder1 {
-  x: ExprInst,
-}
-atomic_redirect!(Remainder1, x);
-atomic_impl!(Remainder1);
-externfn_impl!(Remainder1, |this: &Self, x: ExprInst| {
-  let a: Numeric = this.x.clone().try_into()?;
-  Ok(Remainder0 { a, x })
-});
-
-/// Prev state: [Remainder1]
-#[derive(Debug, Clone)]
-pub struct Remainder0 {
-  a: Numeric,
-  x: ExprInst,
-}
-atomic_redirect!(Remainder0, x);
-atomic_impl!(Remainder0, |Self { a, x }: &Self, _| {
-  let b: Numeric = x.clone().try_into()?;
-  Ok((*a % b).into())
-});

src/stl/num/operators/subtract.rs

@@ -1,36 +0,0 @@
-use std::fmt::Debug;
-
-use super::super::Numeric;
-use crate::representations::interpreted::ExprInst;
-use crate::{atomic_impl, atomic_redirect, externfn_impl};
-
-/// Subtracts two numbers
-///
-/// Next state: [Subtract1]
-#[derive(Clone)]
-pub struct Subtract2;
-externfn_impl!(Subtract2, |_: &Self, x: ExprInst| Ok(Subtract1 { x }));
-
-/// Prev state: [Subtract2]; Next state: [Subtract0]
-#[derive(Debug, Clone)]
-pub struct Subtract1 {
-  x: ExprInst,
-}
-atomic_redirect!(Subtract1, x);
-atomic_impl!(Subtract1);
-externfn_impl!(Subtract1, |this: &Self, x: ExprInst| {
-  let a: Numeric = this.x.clone().try_into()?;
-  Ok(Subtract0 { a, x })
-});
-
-/// Prev state: [Subtract1]
-#[derive(Debug, Clone)]
-pub struct Subtract0 {
-  a: Numeric,
-  x: ExprInst,
-}
-atomic_redirect!(Subtract0, x);
-atomic_impl!(Subtract0, |Self { a, x }: &Self, _| {
-  let b: Numeric = x.clone().try_into()?;
-  Ok((*a - b).into())
-});

src/stl/option.orc

@@ -1,4 +1,4 @@
-import std::panic
+import std::io::panic
 
 export some := \v. \d.\f. f v
 export none := \d.\f. d

src/stl/prelude.orc

@@ -0,0 +1,15 @@
+import std::num::*
+export ::(+, -, *, /, %)
+import std::str::*
+export ::(++)
+import std::bool::*
+export ::(==, if, then, else)
+import std::fn::*
+export ::(loop, on, with, $, |>, =>)
+import std::list
+import std::map
+import std::option
+export ::(list, map, option)
+
+import std::known::*
+export ::(,)

src/stl/proc.orc

@@ -0,0 +1,12 @@
+export do { ...$statement ; ...$rest:1 } =0x2p130=> statement (...$statement) do { ...$rest }
+export do { ...$return } =0x1p130=> ...$return
+
+export statement (let $name = ...$value) ...$next =0x1p230=> (
+  (\$name. ...$next) (...$value)
+)
+export statement (cps $name = ...$operation) ...$next =0x2p230=> (
+  (...$operation) \$name. ...$next
+)
+export statement (cps ...$operation) ...$next =0x1p230=> (
+  (...$operation) (...$next)
+)

src/stl/str.orc

@@ -0,0 +1 @@
+export ...$a ++ ...$b =0x4p36=> (concatenate (...$a) (...$b))

src/stl/str.rs

@@ -0,0 +1,39 @@
+use super::litconv::{with_str, with_uint};
+use super::RuntimeError;
+use crate::interner::Interner;
+use crate::pipeline::ConstTree;
+use crate::{define_fn, Literal};
+
+define_fn! {expr=x in
+  /// Append a string to another
+  pub Concatenate {
+    a: String as with_str(x, |s| Ok(s.clone())),
+    b: String as with_str(x, |s| Ok(s.clone()))
+  } => Ok(Literal::Str(a.to_owned() + b).into())
+}
+
+define_fn! {expr=x in
+  pub CharAt {
+    s: String as with_str(x, |s| Ok(s.clone())),
+    i: u64 as with_uint(x, Ok)
+  } => {
+    if let Some(c) = s.chars().nth(*i as usize) {
+      Ok(Literal::Char(c).into())
+    } else {
+      RuntimeError::fail(
+        "Character index out of bounds".to_string(),
+        "indexing string",
+      )?
+    }
+  }
+}
+
+pub fn str(i: &Interner) -> ConstTree {
+  ConstTree::tree([(
+    i.i("str"),
+    ConstTree::tree([
+      (i.i("concatenate"), ConstTree::xfn(Concatenate)),
+      (i.i("char_at"), ConstTree::xfn(CharAt)),
+    ]),
+  )])
+}

src/stl/str/char_at.rs

@@ -1,24 +0,0 @@
-use super::super::litconv::{with_str, with_uint};
-use super::super::runtime_error::RuntimeError;
-use crate::interpreted::Clause;
-use crate::{write_fn_step, Literal, Primitive};
-
-write_fn_step!(pub CharAt2 > CharAt1);
-write_fn_step!(
-  CharAt1 {}
-  CharAt0 where s = x => with_str(x, |s| Ok(s.clone())) ;
-);
-write_fn_step!(
-  CharAt0 { s: String }
-  i = x => with_uint(x, Ok);
-  {
-    if let Some(c) = s.chars().nth(i as usize) {
-      Ok(Clause::P(Primitive::Literal(Literal::Char(c))))
-    } else {
-      RuntimeError::fail(
-        "Character index out of bounds".to_string(),
-        "indexing string",
-      )?
-    }
-  }
-);

src/stl/str/concatenate.rs

@@ -1,14 +0,0 @@
-use super::super::litconv::with_str;
-use crate::define_fn;
-use crate::representations::interpreted::Clause;
-use crate::representations::{Literal, Primitive};
-
-define_fn! {expr=x in
-  /// Append a string to another
-  pub Concatenate {
-    a: String as with_str(x, |s| Ok(s.clone())),
-    b: String as with_str(x, |s| Ok(s.clone()))
-  } => {
-    Ok(Clause::P(Primitive::Literal(Literal::Str(a.to_owned() + &b))))
-  }
-}

src/stl/str/mod.rs

@@ -1,12 +0,0 @@
-mod char_at;
-mod concatenate;
-
-use crate::interner::Interner;
-use crate::pipeline::ConstTree;
-
-pub fn str(i: &Interner) -> ConstTree {
-  ConstTree::tree([(
-    i.i("concatenate"),
-    ConstTree::xfn(concatenate::Concatenate),
-  )])
-}

src/utils/mod.rs

@@ -3,6 +3,7 @@ mod print_nname;
 mod pushed;
 mod replace_first;
 mod side;
+mod split_max_prefix;
 mod string_from_charset;
 mod substack;
 mod unwrap_or;
@@ -12,6 +13,7 @@ pub use print_nname::sym2string;
 pub use pushed::pushed;
 pub use replace_first::replace_first;
 pub use side::Side;
+pub use split_max_prefix::split_max_prefix;
 pub use substack::{Stackframe, Substack, SubstackIterator};
 pub(crate) use unwrap_or::unwrap_or;
 pub mod iter;

src/utils/split_max_prefix.rs

@@ -0,0 +1,14 @@
+/// Split off the longest prefix accepted by the validator
+#[allow(clippy::type_complexity)] // FIXME couldn't find a good factoring
+pub fn split_max_prefix<'a, T>(
+  path: &'a [T],
+  is_valid: &impl Fn(&[T]) -> bool,
+) -> Option<(&'a [T], &'a [T])> {
+  for split in (0..=path.len()).rev() {
+    let (filename, subpath) = path.split_at(split);
+    if is_valid(filename) {
+      return Some((filename, subpath));
+    }
+  }
+  None
+}

src/utils/substack.rs

@@ -41,17 +41,13 @@ impl<'a, T> Substack<'a, T> {
   }
   /// Create a new frame on top of this substack
   pub fn new_frame(&'a self, item: T) -> Stackframe<'a, T> {
-    Stackframe { item, prev: self, len: self.opt().map_or(1, |s| s.len) }
+    Stackframe { item, prev: self, len: self.opt().map_or(1, |s| s.len + 1) }
   }
   /// obtain the previous stackframe if one exists
   /// TODO: this should return a [Substack]
   pub fn pop(&'a self, count: usize) -> Option<&'a Stackframe<'a, T>> {
     if let Self::Frame(p) = self {
-      if count == 0 {
+      if count == 0 { Some(p) } else { p.prev.pop(count - 1) }
-        Some(p)
-      } else {
-        p.prev.pop(count - 1)
-      }
     } else {
       None
     }

src/utils/unwrap_or.rs

@@ -1,9 +1,13 @@
 /// A macro version of [Option::unwrap_or_else] which supports flow
 /// control statements such as `return` and `break` in the "else" branch.
+/// It also supports unwrapping concrete variants of other enums
 macro_rules! unwrap_or {
   ($m:expr; $fail:expr) => {{
     if let Some(res) = ($m) { res } else { $fail }
   }};
+  ($m:expr => $pattern:path; $fail:expr) => {{
+    if let $pattern(res) = ($m) { res } else { $fail }
+  }};
 }
 
 pub(crate) use unwrap_or;