Import and export improved

- Import paths are now vname and not sym
- Imports and exports accept multiple space-delimited operators in []

as a result, we can now reliably import and export the operator *

- error reporting ergonomics

src/error/import_all.rs

@@ -1,9 +1,7 @@
 use std::rc::Rc;
 
-use super::{ErrorPosition, ProjectError};
+use super::ProjectError;
 use crate::representations::location::Location;
-use crate::utils::iter::box_once;
-use crate::utils::BoxedIter;
 use crate::{Interner, VName};
 
 /// Error produced for the statement `import *`
@@ -22,13 +20,7 @@ impl ProjectError for ImportAll {
     format!("{} imports *", i.extern_all(&self.offender_mod).join("::"))
   }
 
-  fn positions(&self, i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition {
-      location: Location::File(self.offender_file.clone()),
-      message: Some(format!(
-        "{} imports *",
-        i.extern_all(&self.offender_mod).join("::")
-      )),
-    })
+  fn one_position(&self, _i: &Interner) -> Location {
+    Location::File(self.offender_file.clone())
   }
 }

src/error/not_found.rs

@@ -1,11 +1,11 @@
-use super::{ErrorPosition, ProjectError};
+use std::rc::Rc;
+
+use super::ProjectError;
 use crate::representations::project::ProjectModule;
 #[allow(unused)] // For doc
 use crate::tree::Module;
 use crate::tree::WalkError;
-use crate::utils::iter::box_once;
-use crate::utils::BoxedIter;
-use crate::{Interner, NameLike, Tok, VName};
+use crate::{Interner, Location, NameLike, Tok, VName};
 
 /// Error produced when an import refers to a nonexistent module
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
@@ -64,7 +64,7 @@ impl ProjectError for NotFound {
       i.extern_all(&self.file).join("/"),
     )
   }
-  fn positions(&self, i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition::just_file(i.extern_all(&self.file)))
+  fn one_position(&self, i: &Interner) -> crate::Location {
+    Location::File(Rc::new(i.extern_all(&self.file)))
   }
 }

src/error/project_error.rs

@@ -2,6 +2,7 @@ use std::rc::Rc;
 
 use crate::interner::InternedDisplay;
 use crate::representations::location::Location;
+use crate::utils::iter::box_once;
 use crate::utils::BoxedIter;
 use crate::Interner;
 
@@ -14,13 +15,6 @@ pub struct ErrorPosition {
   pub message: Option<String>,
 }
 
-impl ErrorPosition {
-  /// An error position referring to an entire file with no comment
-  pub fn just_file(file: Vec<String>) -> Self {
-    Self { message: None, location: Location::File(Rc::new(file)) }
-  }
-}
-
 /// Errors addressed to the developer which are to be resolved with
 /// code changes
 pub trait ProjectError {
@@ -30,8 +24,16 @@ pub trait ProjectError {
   fn message(&self, _i: &Interner) -> String {
     self.description().to_string()
   }
-  /// Code positions relevant to this error
-  fn positions(&self, i: &Interner) -> BoxedIter<ErrorPosition>;
+  /// Code positions relevant to this error. If you don't implement this, you
+  /// must implement [ProjectError::one_position]
+  fn positions(&self, i: &Interner) -> BoxedIter<ErrorPosition> {
+    box_once(ErrorPosition { location: self.one_position(i), message: None })
+  }
+  /// Short way to provide a single location. If you don't implement this, you
+  /// must implement [ProjectError::positions]
+  fn one_position(&self, _i: &Interner) -> Location {
+    unimplemented!()
+  }
   /// Convert the error into an `Rc<dyn ProjectError>` to be able to
   /// handle various errors together
   fn rc(self) -> Rc<dyn ProjectError>

src/error/too_many_supers.rs

@@ -1,9 +1,7 @@
 use std::rc::Rc;
 
-use super::{ErrorPosition, ProjectError};
+use super::ProjectError;
 use crate::representations::location::Location;
-use crate::utils::iter::box_once;
-use crate::utils::BoxedIter;
 use crate::{Interner, VName};
 
 /// Error produced when an import path starts with more `super` segments
@@ -30,14 +28,7 @@ impl ProjectError for TooManySupers {
     )
   }
 
-  fn positions(&self, i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition {
-      location: Location::File(Rc::new(i.extern_all(&self.offender_file))),
-      message: Some(format!(
-        "path {} in {} contains too many `super` steps.",
-        i.extern_all(&self.path).join("::"),
-        i.extern_all(&self.offender_mod).join("::")
-      )),
-    })
+  fn one_position(&self, i: &Interner) -> Location {
+    Location::File(Rc::new(i.extern_all(&self.offender_file)))
   }
 }

src/error/unexpected_directory.rs

@@ -1,7 +1,7 @@
-use super::{ErrorPosition, ProjectError};
-use crate::utils::iter::box_once;
-use crate::utils::BoxedIter;
-use crate::{Interner, VName};
+use std::rc::Rc;
+
+use super::ProjectError;
+use crate::{Interner, Location, VName};
 
 /// Produced when a stage that deals specifically with code encounters
 /// a path that refers to a directory
@@ -15,9 +15,10 @@ impl ProjectError for UnexpectedDirectory {
     "A stage that deals specifically with code encountered a path that refers \
      to a directory"
   }
-  fn positions(&self, i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition::just_file(i.extern_all(&self.path)))
+  fn one_position(&self, i: &Interner) -> crate::Location {
+    Location::File(Rc::new(i.extern_all(&self.path)))
   }
+
   fn message(&self, i: &Interner) -> String {
     format!(
       "{} was expected to be a file but a directory was found",

src/error/visibility_mismatch.rs

@@ -1,9 +1,7 @@
 use std::rc::Rc;
 
-use super::project_error::{ErrorPosition, ProjectError};
+use super::project_error::ProjectError;
 use crate::representations::location::Location;
-use crate::utils::iter::box_once;
-use crate::utils::BoxedIter;
 use crate::{Interner, VName};
 
 /// Multiple occurences of the same namespace with different visibility
@@ -18,13 +16,13 @@ impl ProjectError for VisibilityMismatch {
   fn description(&self) -> &str {
     "Some occurences of a namespace are exported but others are not"
   }
-  fn positions(&self, i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition {
-      location: Location::File(self.file.clone()),
-      message: Some(format!(
-        "{} is opened multiple times with different visibilities",
-        i.extern_all(&self.namespace).join("::")
-      )),
-    })
+  fn message(&self, i: &Interner) -> String {
+    format!(
+      "{} is opened multiple times with different visibilities",
+      i.extern_all(&self.namespace).join("::")
+    )
+  }
+  fn one_position(&self, _i: &Interner) -> Location {
+    Location::File(self.file.clone())
   }
 }

src/facade/pre_macro.rs

@@ -4,11 +4,9 @@ use std::rc::Rc;
 use hashbrown::HashMap;
 
 use super::{Process, System};
-use crate::error::{ErrorPosition, ProjectError, ProjectResult};
+use crate::error::{ProjectError, ProjectResult};
 use crate::interpreter::HandlerTable;
 use crate::rule::Repo;
-use crate::utils::iter::box_once;
-use crate::utils::BoxedIter;
 use crate::{
   ast, ast_to_interpreted, collect_consts, collect_rules, rule, Interner,
   Location, ProjectTree, Sym,
@@ -128,7 +126,7 @@ impl ProjectError for MacroTimeout {
     )
   }
 
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.location.clone(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.location.clone()
   }
 }

src/facade/process.rs

@@ -1,14 +1,12 @@
 use hashbrown::HashMap;
 
-use crate::error::{ErrorPosition, ProjectError, ProjectResult};
+use crate::error::{ProjectError, ProjectResult};
 use crate::interpreted::{self, ExprInst};
 #[allow(unused)] // for doc
 use crate::interpreter;
 use crate::interpreter::{
   run_handler, Context, HandlerTable, Return, RuntimeError,
 };
-use crate::utils::iter::box_once;
-use crate::utils::BoxedIter;
 use crate::{Interner, Location, Sym};
 
 /// This struct ties the state of systems to loaded code, and allows to call
@@ -84,7 +82,7 @@ impl ProjectError for MissingSymbol {
     )
   }
 
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.location.clone(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.location.clone()
   }
 }

src/foreign_macros/atomic_impl.rs

@@ -41,7 +41,7 @@ use crate::Primitive;
 /// ```
 /// use orchidlang::{Literal};
 /// use orchidlang::interpreted::ExprInst;
-/// use orchidlang::stl::litconv::with_lit;
+/// use orchidlang::systems::cast_exprinst::with_lit;
 /// use orchidlang::{atomic_impl, atomic_redirect, externfn_impl};
 ///
 /// /// Convert a literal to a string using Rust's conversions for floats, chars and

src/foreign_macros/define_fn.rs

@@ -41,7 +41,7 @@ use crate::write_fn_step;
 ///
 /// ```
 /// use orchidlang::interpreted::Clause;
-/// use orchidlang::stl::litconv::with_str;
+/// use orchidlang::systems::cast_exprinst::with_str;
 /// use orchidlang::{define_fn, Literal, Primitive};
 ///
 /// define_fn! {expr=x in
@@ -58,7 +58,7 @@ use crate::write_fn_step;
 /// A simpler format is also offered for unary functions:
 ///
 /// ```
-/// use orchidlang::stl::litconv::with_lit;
+/// use orchidlang::systems::cast_exprinst::with_lit;
 /// use orchidlang::{define_fn, Literal};
 ///
 /// define_fn! {

src/foreign_macros/write_fn_step.rs

@@ -18,14 +18,14 @@ use crate::interpreted::ExprInst;
 /// discussed below. The newly bound names (here `s` and `i` before `=`) can
 /// also receive type annotations.
 ///
-/// ```no_run
+/// ```
 /// // FIXME this is a very old example that wouldn't compile now
 /// use unicode_segmentation::UnicodeSegmentation;
 ///
 /// use orchidlang::{write_fn_step, Literal, Primitive};
 /// use orchidlang::interpreted::Clause;
-/// use orchidlang::stl::litconv::{with_str, with_uint};
-/// use orchidlang::stl::RuntimeError;
+/// use orchidlang::systems::cast_exprinst::{with_str, with_uint};
+/// use orchidlang::systems::RuntimeError;
 ///
 /// // Initial state
 /// write_fn_step!(pub CharAt2 > CharAt1);
@@ -40,7 +40,7 @@ use crate::interpreted::ExprInst;
 ///   i = x => with_uint(x, Ok);
 ///   {
 ///     if let Some(c) = s.graphemes(true).nth(*i as usize) {
-///       Ok(Literal::Char(c.to_string()).into())
+///       Ok(Literal::Str(c.to_string()).into())
 ///     } else {
 ///       RuntimeError::fail(
 ///         "Character index out of bounds".to_string(),

src/interpreter/handler.rs

@@ -1,5 +1,4 @@
 use std::any::{Any, TypeId};
-use std::mem;
 use std::rc::Rc;
 
 use hashbrown::HashMap;
@@ -8,7 +7,6 @@ use trait_set::trait_set;
 use super::{run, Context, Return, RuntimeError};
 use crate::foreign::ExternError;
 use crate::interpreted::{Clause, ExprInst};
-use crate::utils::unwrap_or;
 use crate::Primitive;
 
 trait_set! {
@@ -65,20 +63,15 @@ pub fn run_handler(
 ) -> Result<Return, RuntimeError> {
   loop {
     let ret = run(expr.clone(), ctx.clone())?;
-    if ret.gas == Some(0) {
-      return Ok(ret);
+    if let Clause::P(Primitive::Atom(a)) = &ret.state.expr().clause {
+      if let Some(e) = handlers.dispatch(a.0.as_any()) {
+        expr = e?;
+        ctx.gas = ret.gas;
+        if ret.gas.map_or(true, |g| g > 0) {
+          continue;
+        }
+      }
     }
-    let state_ex = ret.state.expr();
-    let a = if let Clause::P(Primitive::Atom(a)) = &state_ex.clause {
-      a
-    } else {
-      mem::drop(state_ex);
-      return Ok(ret);
-    };
-    expr = unwrap_or!(handlers.dispatch(a.0.as_any()); {
-      mem::drop(state_ex);
-      return Ok(ret)
-    })?;
-    ctx.gas = ret.gas;
+    return Ok(ret);
   }
 }

src/lib.rs

@@ -34,4 +34,4 @@ pub use representations::{
   ast, from_const_tree, interpreted, sourcefile, tree, ConstTree, Literal,
   Location, PathSet, Primitive,
 };
-pub use utils::{Side, Substack, ThreadPool};
+pub use utils::{thread_pool, Side, Substack};

src/parse/errors.rs

@@ -6,7 +6,6 @@ use itertools::Itertools;
 use super::{Entry, Lexeme};
 use crate::error::{ErrorPosition, ProjectError};
 use crate::interner::InternedDisplay;
-use crate::utils::iter::box_once;
 use crate::utils::BoxedIter;
 use crate::{Interner, Location, Tok};
 
@@ -21,8 +20,8 @@ impl ProjectError for LineNeedsPrefix {
   fn message(&self, i: &Interner) -> String {
     format!("{} cannot appear at the beginning of a line", self.entry.bundle(i))
   }
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { message: None, location: self.entry.location() })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.entry.location()
   }
 }
 
@@ -42,8 +41,8 @@ impl ProjectError for UnexpectedEOL {
       .to_string()
   }
 
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { message: None, location: self.entry.location() })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.entry.location()
   }
 }
 
@@ -54,8 +53,8 @@ impl ProjectError for ExpectedEOL {
   fn description(&self) -> &str {
     "Expected the end of the line"
   }
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.location.clone(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.location.clone()
   }
 }
 
@@ -87,8 +86,8 @@ impl ProjectError for ExpectedName {
     }
   }
 
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.entry.location(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.entry.location()
   }
 }
 
@@ -126,8 +125,9 @@ impl ProjectError for Expected {
     let or_name = if self.or_name { " or a name" } else { "" };
     format!("Expected {}{} but found {}", list, or_name, self.found.bundle(i))
   }
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.found.location(), message: None })
+
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.found.location()
   }
 }
 
@@ -143,8 +143,8 @@ impl ProjectError for ReservedToken {
     format!("{} is a reserved token", self.entry.bundle(i))
   }
 
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.entry.location(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.entry.location()
   }
 }
 
@@ -161,8 +161,8 @@ impl ProjectError for BadTokenInRegion {
     format!("{} cannot appear in {}", self.entry.bundle(i), self.region)
   }
 
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.entry.location(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.entry.location()
   }
 }
 
@@ -179,8 +179,8 @@ impl ProjectError for NotFound {
     format!("{} was expected", self.expected)
   }
 
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.location.clone(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.location.clone()
   }
 }
 
@@ -191,8 +191,8 @@ impl ProjectError for LeadingNS {
   fn description(&self) -> &str {
     ":: can only follow a name token"
   }
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.location.clone(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.location.clone()
   }
 }
 
@@ -206,8 +206,8 @@ impl ProjectError for MisalignedParen {
   fn message(&self, i: &Interner) -> String {
     format!("This {} has no pair", self.entry.bundle(i))
   }
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.entry.location(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.entry.location()
   }
 }
 
@@ -218,8 +218,20 @@ impl ProjectError for NamespacedExport {
   fn description(&self) -> &str {
     "Exports can only refer to unnamespaced names in the local namespace"
   }
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.location.clone(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.location.clone()
+  }
+}
+
+pub struct GlobExport {
+  pub location: Location,
+}
+impl ProjectError for GlobExport {
+  fn description(&self) -> &str {
+    "Exports can only refer to concrete names, globstars are not allowed"
+  }
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.location.clone()
   }
 }
 

src/parse/multiname.rs

@@ -1,18 +1,45 @@
 use std::collections::VecDeque;
-use std::iter;
 
 use super::context::Context;
-use super::errors::{Expected, ExpectedName};
+use super::errors::Expected;
 use super::stream::Stream;
 use super::Lexeme;
 use crate::error::{ProjectError, ProjectResult};
-use crate::utils::iter::{box_chain, box_once, BoxedIterIter};
+use crate::sourcefile::Import;
+use crate::utils::iter::{box_chain, box_once};
+use crate::utils::BoxedIter;
 use crate::Tok;
 
+struct Subresult {
+  glob: bool,
+  deque: VecDeque<Tok<String>>,
+}
+impl Subresult {
+  fn new_glob() -> Self {
+    Self { glob: true, deque: VecDeque::new() }
+  }
+
+  fn new_named(name: Tok<String>) -> Self {
+    Self { glob: false, deque: VecDeque::from([name]) }
+  }
+
+  fn push_front(mut self, name: Tok<String>) -> Self {
+    self.deque.push_front(name);
+    self
+  }
+
+  fn finalize(self) -> Import {
+    let Self { mut deque, glob } = self;
+    debug_assert!(glob || !deque.is_empty(), "The constructors forbid this");
+    let name = if glob { None } else { deque.pop_back() };
+    Import { name, path: deque.into() }
+  }
+}
+
 fn parse_multiname_branch(
   cursor: Stream<'_>,
   ctx: impl Context,
-) -> ProjectResult<(BoxedIterIter<Tok<String>>, Stream<'_>)> {
+) -> ProjectResult<(BoxedIter<Subresult>, Stream<'_>)> {
   let comma = ctx.interner().i(",");
   let (subnames, cursor) = parse_multiname_rec(cursor, ctx.clone())?;
   let (delim, cursor) = cursor.trim().pop()?;
@@ -33,30 +60,46 @@ fn parse_multiname_branch(
   }
 }
 
-pub fn parse_multiname_rec(
+fn parse_multiname_rec(
   curosr: Stream<'_>,
   ctx: impl Context,
-) -> ProjectResult<(BoxedIterIter<Tok<String>>, Stream<'_>)> {
+) -> ProjectResult<(BoxedIter<Subresult>, Stream<'_>)> {
+  let star = ctx.interner().i("*");
   let comma = ctx.interner().i(",");
-  let (head, cursor) = curosr.trim().pop()?;
+  let (head, mut cursor) = curosr.trim().pop()?;
   match &head.lexeme {
     Lexeme::LP('(') => parse_multiname_branch(cursor, ctx),
     Lexeme::LP('[') => {
-      let (op_ent, cursor) = cursor.trim().pop()?;
-      let op = ExpectedName::expect(op_ent)?;
-      let (rp_ent, cursor) = cursor.trim().pop()?;
-      Expected::expect(Lexeme::RP('['), rp_ent)?;
-      Ok((box_once(box_once(op)), cursor))
+      let mut names = Vec::new();
+      loop {
+        let head;
+        (head, cursor) = cursor.trim().pop()?;
+        match head.lexeme {
+          Lexeme::Name(n) => names.push(n),
+          Lexeme::RP('[') => break,
+          _ => {
+            let err = Expected {
+              expected: vec![Lexeme::RP('[')],
+              or_name: true,
+              found: head.clone(),
+            };
+            return Err(err.rc());
+          },
+        }
+      }
+      Ok((Box::new(names.into_iter().map(Subresult::new_named)), cursor))
     },
-    Lexeme::Name(n) if *n != comma => {
+    Lexeme::Name(n) if *n == star =>
+      Ok((box_once(Subresult::new_glob()), cursor)),
+    Lexeme::Name(n) if ![comma, star].contains(n) => {
       let cursor = cursor.trim();
       if cursor.get(0).ok().map(|e| &e.lexeme) == Some(&Lexeme::NS) {
         let cursor = cursor.step()?;
         let (out, cursor) = parse_multiname_rec(cursor, ctx)?;
-        let out = Box::new(out.map(|i| box_chain!(i, iter::once(*n))));
+        let out = Box::new(out.map(|sr| sr.push_front(*n)));
         Ok((out, cursor))
       } else {
-        Ok((box_once(box_once(*n)), cursor))
+        Ok((box_once(Subresult::new_named(*n)), cursor))
       }
     },
     _ => Err(
@@ -73,16 +116,7 @@ pub fn parse_multiname_rec(
 pub fn parse_multiname(
   cursor: Stream<'_>,
   ctx: impl Context,
-) -> ProjectResult<(Vec<Vec<Tok<String>>>, Stream<'_>)> {
+) -> ProjectResult<(Vec<Import>, Stream<'_>)> {
   let (output, cont) = parse_multiname_rec(cursor, ctx)?;
-  let output = output
-    .map(|it| {
-      let mut deque = VecDeque::with_capacity(it.size_hint().0);
-      for item in it {
-        deque.push_front(item)
-      }
-      deque.into()
-    })
-    .collect();
-  Ok((output, cont))
+  Ok((output.map(|sr| sr.finalize()).collect(), cont))
 }

src/parse/sourcefile.rs

@@ -5,8 +5,8 @@ use itertools::Itertools;
 
 use super::context::Context;
 use super::errors::{
-  BadTokenInRegion, Expected, ExpectedName, LeadingNS, MisalignedParen,
-  NamespacedExport, ReservedToken, UnexpectedEOL,
+  BadTokenInRegion, Expected, ExpectedName, GlobExport, LeadingNS,
+  MisalignedParen, NamespacedExport, ReservedToken, UnexpectedEOL,
 };
 use super::lexer::Lexeme;
 use super::multiname::parse_multiname;
@@ -71,18 +71,8 @@ pub fn parse_line(
     Lexeme::Const | Lexeme::Macro | Lexeme::Module =>
       Ok(FileEntry::Internal(parse_member(cursor, ctx)?)),
     Lexeme::Import => {
-      let globstar = ctx.interner().i("*");
-      let (names, cont) = parse_multiname(cursor.step()?, ctx.clone())?;
+      let (imports, cont) = parse_multiname(cursor.step()?, ctx)?;
       cont.expect_empty()?;
-      let imports = (names.into_iter())
-        .map(|mut nsname| {
-          let name = nsname.pop().expect("multinames cannot be zero-length");
-          Import {
-            path: ctx.interner().i(&nsname),
-            name: if name == globstar { None } else { Some(name) },
-          }
-        })
-        .collect();
       Ok(FileEntry::Import(imports))
     },
     _ => {
@@ -105,9 +95,12 @@ pub fn parse_export_line(
       let (names, cont) = parse_multiname(cursor.step()?, ctx)?;
       cont.expect_empty()?;
       let names = (names.into_iter())
-        .map(|i| if i.len() == 1 { Some(i[0]) } else { None })
-        .collect::<Option<Vec<_>>>()
-        .ok_or_else(|| NamespacedExport { location: cursor.location() }.rc())?;
+        .map(|Import { name, path }| match (name, &path[..]) {
+          (Some(n), []) => Ok(n),
+          (None, _) => Err(GlobExport { location: cursor.location() }.rc()),
+          _ => Err(NamespacedExport { location: cursor.location() }.rc()),
+        })
+        .collect::<Result<Vec<_>, _>>()?;
       Ok(FileEntry::Export(names))
     },
     Lexeme::Const | Lexeme::Macro | Lexeme::Module =>

src/pipeline/file_loader.rs

@@ -6,13 +6,12 @@ use std::{fs, io};
 use hashbrown::{HashMap, HashSet};
 use rust_embed::RustEmbed;
 
-use crate::error::{ErrorPosition, ProjectError, ProjectResult};
+use crate::error::{ProjectError, ProjectResult};
 #[allow(unused)] // for doc
 use crate::facade::System;
 use crate::interner::Interner;
-use crate::utils::iter::box_once;
-use crate::utils::{BoxedIter, Cache};
-use crate::{Stok, VName};
+use crate::utils::Cache;
+use crate::{Location, Stok, VName};
 
 /// All the data available about a failed source load call
 #[derive(Debug)]
@@ -25,8 +24,8 @@ impl ProjectError for FileLoadingError {
   fn description(&self) -> &str {
     "Neither a file nor a directory could be read from the requested path"
   }
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition::just_file(self.path.clone()))
+  fn one_position(&self, _i: &Interner) -> crate::Location {
+    Location::File(Rc::new(self.path.clone()))
   }
   fn message(&self, _i: &Interner) -> String {
     format!("File: {}\nDirectory: {}", self.file, self.dir)

src/pipeline/import_resolution/collect_aliases.rs

@@ -14,7 +14,10 @@ fn assert_visible(
   target: &[Tok<String>], // may point to a symbol or module of any kind
   project: &ProjectTree<VName>,
 ) -> ProjectResult<()> {
-  let (tgt_item, tgt_path) = unwrap_or!(target.split_last(); return Ok(()));
+  let (tgt_item, tgt_path) = unwrap_or! {
+    target.split_last();
+    return Ok(())
+  };
   let shared_len =
     source.iter().zip(tgt_path.iter()).take_while(|(a, b)| a == b).count();
   let vis_ignored_len = usize::min(tgt_path.len(), shared_len + 1);

src/pipeline/project_tree/build_tree.rs

@@ -75,7 +75,7 @@ fn source_to_module(
     .collect::<Vec<_>>();
   let imports_from = (imports.iter())
     .map(|imp| -> ProjectResult<_> {
-      let mut imp_path_v = i.r(imp.path).clone();
+      let mut imp_path_v = imp.path.clone();
       imp_path_v.push(imp.name.expect("glob imports had just been resolved"));
       let mut abs_path = absolute_path(&path_v, &imp_path_v, i)
         .expect("should have failed in preparsing");

src/pipeline/project_tree/collect_ops/exported_ops.rs

@@ -7,7 +7,7 @@ use crate::error::{NotFound, ProjectError, ProjectResult};
 use crate::interner::{Interner, Tok};
 use crate::pipeline::source_loader::LoadedSourceTable;
 use crate::representations::tree::WalkErrorKind;
-use crate::utils::{split_max_prefix, unwrap_or, Cache};
+use crate::utils::{split_max_prefix, Cache};
 use crate::Sym;
 
 pub type OpsResult = ProjectResult<Rc<HashSet<Tok<String>>>>;
@@ -33,40 +33,43 @@ pub fn collect_exported_ops(
 ) -> OpsResult {
   let injected = injected(path).unwrap_or_else(|| Rc::new(HashSet::new()));
   let path_s = &i.r(path)[..];
-  let name_split = split_max_prefix(path_s, &|n| loaded.contains_key(n));
-  let (fpath, subpath) = unwrap_or!(name_split; return Ok(Rc::new(
-    (loaded.keys())
-      .filter_map(|modname| {
-        if path_s.len() == coprefix(path_s.iter(), modname.iter()) {
-          Some(modname[path_s.len()])
-        } else {
-          None
-        }
-      })
-      .chain(injected.iter().copied())
-      .collect::<HashSet<_>>(),
-  )));
-  let preparsed = &loaded[fpath].preparsed;
-  let module =
-    preparsed.0.walk_ref(subpath, false).map_err(
-      |walk_err| match walk_err.kind {
-        WalkErrorKind::Private => {
-          unreachable!("visibility is not being checked here")
+  match split_max_prefix(path_s, &|n| loaded.contains_key(n)) {
+    None => {
+      let ops = (loaded.keys())
+        .filter_map(|modname| {
+          if path_s.len() == coprefix(path_s.iter(), modname.iter()) {
+            Some(modname[path_s.len()])
+          } else {
+            None
+          }
+        })
+        .chain(injected.iter().copied())
+        .collect::<HashSet<_>>();
+      Ok(Rc::new(ops))
+    },
+    Some((fpath, subpath)) => {
+      let preparsed = &loaded[fpath].preparsed;
+      let module = preparsed.0.walk_ref(subpath, false).map_err(
+        |walk_err| match walk_err.kind {
+          WalkErrorKind::Private => {
+            unreachable!("visibility is not being checked here")
+          },
+          WalkErrorKind::Missing => NotFound {
+            source: None,
+            file: fpath.to_vec(),
+            subpath: subpath[..walk_err.pos].to_vec(),
+          }
+          .rc(),
         },
-        WalkErrorKind::Missing => NotFound {
-          source: None,
-          file: fpath.to_vec(),
-          subpath: subpath[..walk_err.pos].to_vec(),
-        }
-        .rc(),
-      },
-    )?;
-  let out = (module.items.iter())
-    .filter(|(_, v)| v.exported)
-    .map(|(k, _)| *k)
-    .chain(injected.iter().copied())
-    .collect::<HashSet<_>>();
-  Ok(Rc::new(out))
+      )?;
+      let out = (module.items.iter())
+        .filter(|(_, v)| v.exported)
+        .map(|(k, _)| *k)
+        .chain(injected.iter().copied())
+        .collect::<HashSet<_>>();
+      Ok(Rc::new(out))
+    },
+  }
 }
 
 pub fn mk_cache<'a>(

src/pipeline/project_tree/collect_ops/ops_for.rs

@@ -44,7 +44,7 @@ pub fn collect_ops_for(
       ret.insert(n);
     } else {
       let path = i.expect(
-        import_abs_path(file, modpath, &i.r(import.path)[..], i),
+        import_abs_path(file, modpath, &import.path, i),
         "This error should have been caught during loading",
       );
       ret.extend(ops_cache.find(&i.i(&path))?.iter().copied());

src/pipeline/project_tree/normalize_imports.rs

@@ -59,7 +59,7 @@ fn entv_rec(
           .flat_map(|import| {
             if let Import { name: None, path } = import {
               let p = i.expect(
-                import_abs_path(mod_path, mod_stack, &i.r(path)[..], i),
+                import_abs_path(mod_path, mod_stack, &path, i),
                 "Should have emerged in preparsing",
               );
               let names = i.expect(
@@ -67,7 +67,7 @@ fn entv_rec(
                 "Should have emerged in second parsing",
               );
               let imports = (names.iter())
-                .map(move |&n| Import { name: Some(n), path })
+                .map(|&n| Import { name: Some(n), path: path.clone() })
                 .collect::<Vec<_>>();
               Box::new(imports.into_iter()) as BoxedIter<Import>
             } else {

src/pipeline/source_loader/load_source.rs

@@ -56,7 +56,7 @@ fn load_abs_path_rec(
     // recurse on all imported modules
     preparsed.0.visit_all_imports(&mut |modpath, _module, import| {
       let abs_pathv =
-        import_abs_path(filename, modpath, &import.nonglob_path(i), i)?;
+        import_abs_path(filename, modpath, &import.nonglob_path(), i)?;
       if abs_path.starts_with(&abs_pathv) {
         return Ok(());
       }

src/representations/ast_to_postmacro.rs

@@ -2,9 +2,8 @@ use std::rc::Rc;
 
 use super::location::Location;
 use super::{ast, postmacro};
-use crate::error::{ErrorPosition, ProjectError};
-use crate::utils::iter::box_once;
-use crate::utils::{BoxedIter, Substack};
+use crate::error::ProjectError;
+use crate::utils::Substack;
 use crate::{Interner, Sym};
 
 #[derive(Debug, Clone)]
@@ -51,9 +50,8 @@ impl ProjectError for Error {
       _ => self.description().to_string(),
     }
   }
-
-  fn positions(&self, _i: &Interner) -> BoxedIter<ErrorPosition> {
-    box_once(ErrorPosition { location: self.location.clone(), message: None })
+  fn one_position(&self, _i: &Interner) -> Location {
+    self.location.clone()
   }
 }
 

src/representations/sourcefile.rs

@@ -7,11 +7,10 @@ use super::namelike::VName;
 use crate::ast::{Constant, Rule};
 use crate::interner::{Interner, Tok};
 use crate::utils::{unwrap_or, BoxedIter};
-use crate::Sym;
 
 /// An import pointing at another module, either specifying the symbol to be
 /// imported or importing all available symbols with a globstar (*)
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Import {
   /// Import path, a sequence of module names. Can either start with
   ///
@@ -19,7 +18,7 @@ pub struct Import {
   /// - any number of `super` to reference the parent module of the implied
   ///   `self`
   /// - a root name
-  pub path: Sym,
+  pub path: VName,
   /// If name is None, this is a wildcard import
   pub name: Option<Tok<String>>,
 }
@@ -29,8 +28,8 @@ impl Import {
   ///
   /// Returns the path if this is a glob import, or the path plus the
   /// name if this is a specific import
-  pub fn nonglob_path(&self, i: &Interner) -> Vec<Tok<String>> {
-    let mut path_vec = i.r(self.path).clone();
+  pub fn nonglob_path(&self) -> Vec<Tok<String>> {
+    let mut path_vec = self.path.clone();
     if let Some(n) = self.name {
       path_vec.push(n)
     }

src/systems/io/facade.rs

@@ -145,7 +145,7 @@ impl<'a, P: MessagePort, ST: StreamTable + 'a> IntoSystem<'a>
       constants: io_bindings(i, streams).unwrap_tree(),
       code: embed_to_map::<IOEmbed>(".orc", i),
       prelude: vec![FileEntry::Import(vec![Import {
-        path: i.i(&vec![i.i("system"), i.i("io"), i.i("prelude")]),
+        path: vec![i.i("system"), i.i("io"), i.i("prelude")],
         name: None,
       }])],
       handlers,

src/systems/io/flow.rs

@@ -5,8 +5,8 @@ use hashbrown::HashMap;
 
 use crate::foreign::ExternError;
 use crate::systems::asynch::MessagePort;
-use crate::utils::{take_with_output, Task};
-use crate::ThreadPool;
+use crate::thread_pool::{Task, ThreadPool};
+use crate::utils::take_with_output;
 
 pub trait StreamHandle: Clone + Send {
   fn new(id: usize) -> Self;

src/systems/stl/prelude.orc

@@ -1,11 +1,11 @@
 import std::num::*
-export ::(+, -, *, /, %)
+export ::[+ - * / %]
 import std::str::*
 export ::[++]
 import std::bool::*
-export ::(==, if, then, else, true, false)
+export ::([==], if, then, else, true, false)
 import std::fn::*
-export ::($, |>, =>, identity, pass, pass2, return)
+export ::([$ |> =>], identity, pass, pass2, return)
 import std::list
 import std::map
 import std::option

src/systems/stl/stl_system.rs

@@ -41,7 +41,7 @@ impl IntoSystem<'static> for StlConfig {
       constants: HashMap::from([(i.i("std"), fns)]),
       code: embed_to_map::<StlEmbed>(".orc", i),
       prelude: vec![FileEntry::Import(vec![Import {
-        path: i.i(&[i.i("std"), i.i("prelude")][..]),
+        path: vec![i.i("std"), i.i("prelude")],
         name: None,
       }])],
       handlers: HandlerTable::new(),

src/utils/iter.rs

@@ -5,8 +5,6 @@ use std::iter;
 /// A trait object of [Iterator] to be assigned to variables that may be
 /// initialized form multiple iterators of incompatible types
 pub type BoxedIter<'a, T> = Box<dyn Iterator<Item = T> + 'a>;
-/// A [BoxedIter] of [BoxedIter].
-pub type BoxedIterIter<'a, T> = BoxedIter<'a, BoxedIter<'a, T>>;
 /// creates a [BoxedIter] of a single element
 pub fn box_once<'a, T: 'a>(t: T) -> BoxedIter<'a, T> {
   Box::new(iter::once(t))

src/utils/mod.rs

@@ -11,7 +11,7 @@ mod split_max_prefix;
 mod string_from_charset;
 mod substack;
 mod take_with_output;
-mod thread_pool;
+pub mod thread_pool;
 mod unwrap_or;
 
 pub use cache::Cache;
@@ -30,4 +30,3 @@ pub use iter::BoxedIter;
 pub use iter_find::iter_find;
 pub use string_from_charset::string_from_charset;
 pub use take_with_output::take_with_output;
-pub use thread_pool::{Query, QueryTask, Task, ThreadPool};

src/utils/thread_pool.rs

@@ -1,3 +1,7 @@
+//! A thread pool for executing tasks in parallel, spawning threads as workload
+//! increases and terminating them as tasks finish. This is not terribly
+//! efficient, its main design goal is to parallelize blocking I/O calls.
+
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::mpsc::{sync_channel, SyncSender};
 use std::sync::{Arc, Mutex};
@@ -6,6 +10,8 @@ use std::thread::spawn;
 /// A trait for a task dispatched on a [ThreadPool]. The task owns all relevant
 /// data, is safe to pass between threads and is executed only once.
 pub trait Task: Send + 'static {
+  /// Execute the task. At a minimum, this involves signaling some other thread,
+  /// otherwise the task has no effect.
   fn run(self);
 }
 
@@ -15,10 +21,21 @@ impl<F: FnOnce() + Send + 'static> Task for F {
   }
 }
 
+/// An async unit of work that produces some result, see [Task]. This can be
+/// wrapped in a generic reporter to create a task.
 pub trait Query: Send + 'static {
+  /// The value produced by the query
   type Result: Send + 'static;
 
+  /// Execute the query, producing some value which can then be sent to another
+  /// thread
   fn run(self) -> Self::Result;
+
+  /// Associate the query with a reporter expressed in a plain function.
+  /// Note that because every lambda has a distinct type and every thread pool
+  /// runs exactly one type of task, this can appear only once in the code for
+  /// a given thread pool. It is practical in a narrow set of cases, most of the
+  /// time however you are better off defining an explicit reporter.
   fn then<F: FnOnce(Self::Result) + Send + 'static>(
     self,
     callback: F,
@@ -37,6 +54,8 @@ impl<F: FnOnce() -> R + Send + 'static, R: Send + 'static> Query for F {
   }
 }
 
+/// A reporter that calls a statically known function with the result of a
+/// query. Constructed with [Query::then]
 pub struct QueryTask<Q: Query, F: FnOnce(Q::Result) + Send + 'static> {
   query: Q,
   callback: F,
@@ -68,16 +87,23 @@ struct ThreadPoolData<T: Task> {
 /// arrive. To get rid of the last waiting thread, drop the thread pool.
 ///
 /// ```
-/// use orchidlang::ThreadPool;
+/// use orchidlang::thread_pool::{Task, ThreadPool};
 ///
-/// let pool = ThreadPool::new(|s: String, _| println!("{}", s));
+/// struct MyTask(&'static str);
+/// impl Task for MyTask {
+///   fn run(self) {
+///     println!("{}", self.0)
+///   }
+/// }
+///
+/// let pool = ThreadPool::new();
 ///
 /// // spawns first thread
-/// pool.submit("foo".to_string());
+/// pool.submit(MyTask("foo"));
 /// // probably spawns second thread
-/// pool.submit("bar".to_string());
+/// pool.submit(MyTask("bar"));
 /// // either spawns third thread or reuses first
-/// pool.submit("baz".to_string());
+/// pool.submit(MyTask("baz"));
 /// ```
 pub struct ThreadPool<T: Task> {
   data: Arc<ThreadPoolData<T>>,

src/utils/unwrap_or.rs

@@ -8,10 +8,14 @@
 /// It also supports unwrapping concrete variants of other enums
 ///
 /// ```ignore
-/// use crate::representations::Literal;
+/// use crate::Literal;
 ///
 /// crate::unwrap_or!(Literal::Usize(2) => Literal::Number; return)
 /// ```
+///
+/// Note: this macro influences the control flow of the surrounding code
+/// without an `if`, which can be misleading. It should only be used for small,
+/// straightforward jumps.
 macro_rules! unwrap_or {
   ($m:expr; $fail:expr) => {{
     if let Some(res) = ($m) { res } else { $fail }