diff --git a/Cargo.lock b/Cargo.lock
index 0a2bd0d..ba42476 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -54,6 +54,17 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7a81dae078cea95a014a339291cec439d2f232ebe854a9d672b796c6afafa9b7"
 
+[[package]]
+name = "derivative"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fcc3dd5e9e9c0b295d6e1e4d811fb6f157d5ffd784b8d202fc62eac8035a770b"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.2.6"
@@ -82,6 +93,7 @@ name = "orchid"
 version = "0.1.0"
 dependencies = [
  "chumsky",
+ "derivative",
  "thiserror",
 ]
 
diff --git a/Cargo.toml b/Cargo.toml
index 54f3296..90e40b3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,4 +7,5 @@ edition = "2021"
 
 [dependencies]
 thiserror = "1.0"
-chumsky = "0.8"
\ No newline at end of file
+chumsky = "0.8"
+derivative = "2.2"
\ No newline at end of file
diff --git a/README.md b/README.md
index 7cea890..034f194 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,274 @@
-Orchid will be a functional language with a powerful macro language and
-optimizer. Further explanation and demos coming soon!
\ No newline at end of file
+Orchid will be a compiled functional language with a powerful macro
+language and optimizer.
+
+# Examples
+
+Hello World in Orchid
+```orchid
+import std::io::(println, out)
+
+main = println out "Hello World!"
+```
+
+Basic command line calculator
+```orchid
+import std::io::(readln, printf, in, out)
+
+main = (
+    readln in >>= int |> \a. 
+    readln in >>= \op.
+    readln in >>= int |> \b.
+    printf out "the result is {}\n", [match op (
+        "+" => a + b,
+        "-" => a - b,
+        "*" => a * b,
+        "/" => a / b
+    )]
+)
+```
+
+Grep
+```orchid
+import std::io::(readln, println, in, out, getarg)
+
+main = loop \r. (
+    readln in >>= \line.
+    if (substring (getarg 1) line)
+    then (println out ln >>= r)
+    else r
+)
+```
+
+Filter through an arbitrary collection
+```orchid
+filter = @C:Type -> Type. @:Map C. @T. @U. \f:T -> U. \coll:C T. (
+    coll >> \el. if (f el) then (Some el) else Nil
+):(C U)
+```
+
+# Explanation
+
+This explanation is not a tutorial. It follows a constructive order,
+gradually introducing language features to better demonstrate their
+purpose. It also assumes that the reader is familiar with functional
+programming.
+
+## Lambda calculus recap
+
+The language is almost entirely based on lambda calculus, so everything
+is immutable and evaluation is lazy. The following is an anonymous
+function that takes an integer argument and multiplies it by 2:
+
+```orchid
+\x:int. imul 2 x
+```
+
+Multiple parameters are represented using currying, so the above is
+equivalent to
+
+```orchid
+imul 2
+```
+
+Recursion is accomplished using the Y combinator (called `loop`), which
+is a function that takes a function as its single parameter and applies
+it to itself. A naiive implementation of `imul` might look like this.
+
+```orchid
+\a:int.\b:int. loop \r. (\i.
+    ifthenelse (ieq i 0)
+        b
+        (iadd b (r (isub i 1))
+) a
+```
+
+`ifthenelse` takes a boolean as its first parameter and selects one of the
+following two expressions (of identical type) accordingly. `ieq`, `iadd`
+and `isub` are self explanatory.
+
+## Auto parameters (generics, polymorphism)
+
+Although I didin't specify the type of `i` in the above example, it is
+known at compile time because the recursion is applied to b which is an
+integer. I could have omitted the second argument but then I would have
+had to specify `i`'s type as an integer, because for plain lambda
+expressions all types have to be statically knoqn at compile time. To
+achieve polymorphism, one parametric tool is available, called auto
+parameters. An auto parameter is a placeholder filled in during
+compilation, syntactically remarkably similar to lambda expressions:
+
+```orchid
+@T. --[ body of expression referencing T ]--
+```
+
+Autos have two closely related uses. First, they are used to represent
+generic type parameters. If an auto is used as the type of an argument
+or some other subexpression that can be trivially deduced from the calling
+context, it is filled in.
+
+The second usage of autos is for constraints, if they have a type that
+references another auto. Because these parameters are filled in by the
+compiler, referencing them is equivalent to the statement that a default
+value assignable to the specified type exists. Default values are declared
+explicitly and identified by their type, where that type itself may be
+parametric and may specify its own constraints which are resolved
+recursively. If the referenced default is itself a useful value or
+function you can give it a name and use it as such, but you can also omit
+the name, using the default as a hint to the compiler to be able to call
+functions that also have defaults of the same types, or possibly other
+types whose defaults have implmentations based on your defaults.
+
+For a demonstration, here's a sample implementation of the Option monad.
+```orchid
+--[[ The definition of Monad ]]--
+Bind = \M:Type -> Type. @T -> @U -> (T -> M U) -> M T -> M U
+Return = \M:Type -> Type. @T -> T -> M T
+Monad = \M:Type -> Type. (
+    @:Bind M.
+    @:Return M.
+    0 --[ Note that empty expressions are forbidden so those that exist
+        purely for their constraints should return a nondescript constant
+        that is likely to raise a type error when used by mistake, such as
+        zero ]--
+)
+
+--[[ The definition of Option ]]--
+export Option = \T:Type. @U -> U -> (T -> U) -> U
+--[ Constructors ]--
+export Some = @T. \data:T. ( \default. \map. map data ):(Option T)
+export None = @T.          ( \default. \map. default  ):(Option T)
+--[ Implement Monad ]--
+default returnOption = Some:(Return Option)
+default bindOption = ( @T:Type. @U:Type.
+    \f:T -> U. \opt:Option T. opt None f
+):(Bind Option)
+--[ Sample function that works on unknown monad to demonstrate HKTs.
+    Turns (Option (M T)) into (M (Option T)), "raising" the unknown monad
+    out of the Option ]--
+export raise = @M:Type -> Type. @T:Type. @:Monad M. \opt:Option (M T). (
+    opt (return None) (\m. bind m (\x. Some x))
+):(M (Option T))
+```
+
+Defaults may be defined in any module that also defines at least one of
+the types in the definition, which includes both the type of the
+expression and the types of its auto parameters. They always have a name,
+which can be used to override known defaults with which your definiton
+may overlap. For example, if addition is defined elementwise for all
+applicative functors, the author of List might want for concatenation to
+take precedence in the case where all element types match. Notice how
+Add has three arguments, two are the types of the operands and one is
+the result:
+
+```orchid
+default concatListAdd replacing applicativeAdd = @T. (
+    ...
+):(Add (List T) (List T) (List T))
+```
+
+For completeness' sake, the original definition might look like this:
+
+```orchid
+default elementwiseAdd = @C:Type -> Type. @T. @U. @V. @:(Applicative C). @:(Add T U V). (
+    ...
+):(Add (C T) (C U) (C V))
+```
+
+With the use of autos, here's what the recursive multiplication
+implementation looks like:
+
+```orchid
+default iterativeMultiply = @T. @:(Add T T T). (
+    \a:int.\b:T. loop \r. (\i.
+        ifthenelse (ieq i 0)
+            b
+            (add b (r (isub i 1)) -- notice how iadd is now add
+    ) a
+):(Multiply T int T)
+```
+
+This could then be applied to any type that's closed over addition
+
+```orchid
+aroundTheWorldLyrics = (
+    mult 18 (add (mult 4 "Around the World\n") "\n")
+)
+```
+
+## Preprocessor
+
+The above code samples have one notable difference from the Examples
+section above; they're ugly and hard to read. The solution to this is a
+powerful preprocessor which is used internally to define all sorts of
+syntax sugar from operators to complex syntax patterns and even pattern
+matching, and can also be used to define custom syntax. The preprocessor
+executes substitution rules on the S-tree which have a real numbered
+priority and an internal order of resolution.
+
+In the following example, seq matches a list of arbitrary tokens and its
+parameter is the order of resolution. The order can be used for example to
+make sure that `if a then b else if c then d else e` becomes
+`(ifthenelse a b (ifthenelse c d e))` and not
+`(ifthenelse a b if) c then d else e`. It's worth highlighting here that
+preprocessing works on the typeless AST and matchers are constructed
+using inclusion rather than exclusion, so it would not be possible to
+selectively allow the above example without enforcing that if-statements
+are searched back-to-front. If order is still a problem, you can always
+parenthesize problematic expressions.
+
+```orchid
+(...$pre:(seq 2) if $1 then $2 else $3 ...$post:(seq 1)) =2=> (
+    ...$pre
+    (ifthenelse $1 $2 $3)
+    ...$post
+)
+$a + $b =10=> (add $a $b)
+$a == $b =5=> (eq $a $b)
+$a - $b =10=> (sub $a $b)
+```
+
+The recursive addition function now looks like this
+
+```orchid
+default iterativeMultiply = @T. @:(Add T T T). (
+    \a:int.\b:T. loop \r. (\i.
+        if (i == 0) then b
+        else (b + (r (i - 1)))
+    ) a
+):(Multiply T int T)
+```
+
+### Traversal using carriages
+
+While it may not be immediately apparent, these substitution rules are
+actually Turing complete. They can be used quite intuitively to traverse
+the token tree with unique "carriage" symbols that move according to their
+environment and can carry structured data payloads.
+
+TODO: carriage example
+
+# Module system
+
+Files are the smallest unit of namespacing, automatically grouped into
+folders and forming a tree the leaves of which are the actual symbols. An
+exported symbol is a name referenced in an exported substitution pattern
+or assigned to an exported function. Imported symbols are considered
+identical to the same symbol directly imported from the same module for
+the purposes of substitution.
+
+# Optimization
+
+This is very far away so I don't want to make promises, but I have some
+ideas. 
+
+[ ] early execution of functions on any subset of their arguments where it
+    could provide substantial speedup
+[ ] tracking copies of expressions and evaluating them only once
+[ ] Many cases of single recursion converted to loops
+    [ ] tail recursion
+    [ ] 2 distinct loops where the tail doesn't use the arguments
+        [ ] reorder operations to favour this scenario 
+[ ] reactive calculation of values that are deemed to be read more often
+    than written
+[ ] automatic profiling based on performance metrics generated by debug
+    builds
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 9dd3550..e0e31ab 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,6 +1,6 @@
 use std::io::{self, Read};
 
-use chumsky::Parser;
+use chumsky::{Parser, prelude::*};
 
 mod parse;
 
@@ -8,6 +8,7 @@ fn main() {
     let mut input = String::new();
     let mut stdin = io::stdin();
     stdin.read_to_string(&mut input).unwrap();
-    let output = parse::parser().parse(input);
+    let ops: Vec<String> = vec!["$", "."].iter().map(|&s| s.to_string()).collect();
+    let output = parse::expression_parser(&ops).then_ignore(end()).parse(input);
     println!("\nParsed:\n{:?}", output);
 }
diff --git a/src/parse.rs b/src/parse.rs
deleted file mode 100644
index eab8242..0000000
--- a/src/parse.rs
+++ /dev/null
@@ -1,143 +0,0 @@
-use std::fmt::Debug;
-use chumsky::{self, prelude::*, Parser};
-
-#[derive(Debug)]
-pub enum Expr {
-    Num(f64),
-    Int(u64),
-    Char(char),
-    Str(String),
-    Name(String),
-    S(Vec<Expr>),
-    Lambda(String, Vec<Expr>)
-}
-
-fn uint_parser(base: u32) -> impl Parser<char, u64, Error = Simple<char>> {
-    text::int(base).map(move |s: String| u64::from_str_radix(&s, base).unwrap())
-}
-
-fn e_parser() -> impl Parser<char, i32, Error = Simple<char>> {
-    return choice((
-        just('e')
-            .ignore_then(text::int(10))
-            .map(|s: String| s.parse().unwrap()),
-        just("e-")
-            .ignore_then(text::int(10))
-            .map(|s: String| -s.parse::<i32>().unwrap()),
-        empty().map(|()| 0)
-    ))
-}
-
-fn nat2u(base: u64) -> impl Fn((u64, i32),) -> u64 {
-    return move |(val, exp)| {
-        if exp == 0 {val}
-        else {val * base.checked_pow(exp.try_into().unwrap()).unwrap()}
-    };
-}
-
-fn nat2f(base: u64) -> impl Fn((f64, i32),) -> f64 {
-    return move |(val, exp)| {
-        if exp == 0 {val}
-        else {val * (base as f64).powf(exp.try_into().unwrap())}
-    }
-}
-
-fn e_uint_parser(base: u32) -> impl Parser<char, u64, Error = Simple<char>> {
-    if base > 14 {panic!("exponential in base that uses the digit 'e' is ambiguous")}
-    uint_parser(base).then(e_parser()).map(nat2u(base.into()))
-}
-
-fn int_parser() -> impl Parser<char, u64, Error = Simple<char>> {
-    choice((
-        just("0b").ignore_then(e_uint_parser(2)),
-        just("0x").ignore_then(uint_parser(16)),
-        just('0').ignore_then(e_uint_parser(8)),
-        e_uint_parser(10), // Dec has no prefix
-    ))
-}
-
-fn dotted_parser(base: u32) -> impl Parser<char, f64, Error = Simple<char>> {
-    uint_parser(base)
-    .then_ignore(just('.'))
-    .then(text::digits(base))
-    .map(move |(wh, frac)| {
-        let frac_num = u64::from_str_radix(&frac, base).unwrap() as f64;
-        let dexp = base.pow(frac.len().try_into().unwrap());
-        wh as f64 + (frac_num / dexp as f64)
-    })
-}
-
-fn e_float_parser(base: u32) -> impl Parser<char, f64, Error = Simple<char>> {
-    if base > 14 {panic!("exponential in base that uses the digit 'e' is ambiguous")}
-    dotted_parser(base).then(e_parser()).map(nat2f(base.into()))
-}
-
-fn float_parser() -> impl Parser<char, f64, Error = Simple<char>> {
-    choice((
-        just("0b").ignore_then(e_float_parser(2)),
-        just("0x").ignore_then(dotted_parser(16)),
-        just('0').ignore_then(e_float_parser(8)),
-        e_float_parser(10),
-    ))
-}
-
-fn text_parser(delim: char) -> impl Parser<char, char, Error = Simple<char>> {
-    let escape = just('\\').ignore_then(
-        just('\\')
-            .or(just('/'))
-            .or(just('"'))
-            .or(just('b').to('\x08'))
-            .or(just('f').to('\x0C'))
-            .or(just('n').to('\n'))
-            .or(just('r').to('\r'))
-            .or(just('t').to('\t'))
-            .or(just('u').ignore_then(
-                filter(|c: &char| c.is_digit(16))
-                    .repeated()
-                    .exactly(4)
-                    .collect::<String>()
-                    .validate(|digits, span, emit| {
-                        char::from_u32(u32::from_str_radix(&digits, 16).unwrap())
-                            .unwrap_or_else(|| {
-                                emit(Simple::custom(span, "invalid unicode character"));
-                                '\u{FFFD}' // unicode replacement character
-                            })
-                    }),
-            )),
-    );
-    filter(move |&c| c != '\\' && c != delim).or(escape)
-}
-
-fn char_parser() -> impl Parser<char, char, Error = Simple<char>> {
-    just('\'').ignore_then(text_parser('\'')).then_ignore(just('\''))
-}
-
-fn str_parser() -> impl Parser<char, String, Error = Simple<char>> {
-    just('"')
-    .ignore_then(text_parser('"').repeated())
-    .then_ignore(just('"'))
-    .collect()
-}
-
-pub fn parser() -> impl Parser<char, Expr, Error = Simple<char>> {
-    return recursive(|expr| {
-        let lambda = just('\\')
-            .ignore_then(text::ident())
-            .then_ignore(just('.'))
-            .then(expr.clone().repeated().at_least(1))
-            .map(|(name, body)| Expr::Lambda(name, body));
-        let sexpr = expr.clone()
-            .repeated()
-            .delimited_by(just('('), just(')'))
-            .map(Expr::S);
-        choice((
-            float_parser().map(Expr::Num),
-            int_parser().map(Expr::Int),
-            char_parser().map(Expr::Char),
-            str_parser().map(Expr::Str),
-            text::ident().map(Expr::Name),
-            sexpr,
-            lambda
-        )).padded()
-    }).then_ignore(end())
-}
\ No newline at end of file
diff --git a/src/parse/expression.rs b/src/parse/expression.rs
new file mode 100644
index 0000000..35da5a2
--- /dev/null
+++ b/src/parse/expression.rs
@@ -0,0 +1,72 @@
+use std::{fmt::Debug};
+use chumsky::{self, prelude::*, Parser};
+
+use super::string;
+use super::number;
+use super::misc;
+use super::name;
+
+#[derive(Debug)]
+pub enum Expr {
+    Num(f64),
+    Int(u64),
+    Char(char),
+    Str(String),
+    Name(String),
+    S(Vec<Expr>),
+    Lambda(String, Option<Box<Expr>>, Vec<Expr>),
+    Auto(Option<String>, Option<Box<Expr>>, Vec<Expr>),
+    Typed(Box<Expr>, Box<Expr>)
+}
+
+fn typed_parser<'a>(
+    expr: Recursive<'a, char, Expr, Simple<char>>,
+    ops: &'a [String]
+) -> impl Parser<char, Expr, Error = Simple<char>> + 'a {
+    just(':').ignore_then(expr)
+}
+
+fn untyped_xpr_parser<'a>(
+    expr: Recursive<'a, char, Expr, Simple<char>>,
+    ops: &'a [String]
+) -> impl Parser<char, Expr, Error = Simple<char>> + 'a {
+    let lambda = just('\\')
+        .ignore_then(name::name_parser(ops))
+        .then(typed_parser(expr.clone(), ops).or_not())
+        .then_ignore(just('.'))
+        .then(expr.clone().repeated().at_least(1))
+        .map(|((name, t), body)| Expr::Lambda(name, t.map(Box::new), body));
+    let auto = just('@')
+        .ignore_then(name::name_parser(ops).or_not())
+        .then(typed_parser(expr.clone(), ops).or_not())
+        .then_ignore(just('.'))
+        .then(expr.clone().repeated().at_least(1))
+        .map(|((name, t), body)| Expr::Auto(name, t.map(Box::new), body));
+    let sexpr = expr.clone()
+        .repeated()
+        .delimited_by(just('('), just(')'))
+        .map(Expr::S);
+    choice((
+        number::float_parser().map(Expr::Num),
+        number::int_parser().map(Expr::Int),
+        string::char_parser().map(Expr::Char),
+        string::str_parser().map(Expr::Str),
+        name::name_parser(ops).map(Expr::Name),
+        sexpr,
+        lambda,
+        auto
+    )).padded()
+}
+
+pub fn expression_parser(ops: &[String]) -> impl Parser<char, Expr, Error = Simple<char>> + '_ {
+    return recursive(|expr| {
+        return misc::comment_parser().or_not().ignore_then(
+            untyped_xpr_parser(expr.clone(), &ops)
+                .then(typed_parser(expr, ops).or_not())
+                .map(|(val, t)| match t {
+                    Some(typ) => Expr::Typed(Box::new(val), Box::new(typ)),
+                    None => val
+                })
+        ).then_ignore(misc::comment_parser().or_not())
+    })
+}
\ No newline at end of file
diff --git a/src/parse/import.rs b/src/parse/import.rs
new file mode 100644
index 0000000..57d0c75
--- /dev/null
+++ b/src/parse/import.rs
@@ -0,0 +1,58 @@
+use chumsky::{Parser, prelude::*, text::Character};
+use super::name;
+
+enum Import {
+    Name(Vec<String>, String),
+    All(Vec<String>)
+}
+
+fn prefix(pre: Vec<String>, im: Import) -> Import {
+    match im {
+        Import::Name(ns, name) => Import::Name(
+            pre.into_iter().chain(ns.into_iter()).collect(),
+            name
+        ),
+        Import::All(ns) => Import::All(
+            pre.into_iter().chain(ns.into_iter()).collect()
+        )
+    }
+}
+
+
+type BoxedStrIter = Box<dyn Iterator<Item = String>>;
+type BoxedStrIterIter = Box<dyn Iterator<Item = BoxedStrIter>>;
+
+fn init_table(name: String) -> BoxedStrIterIter {
+    Box::new(vec![Box::new(vec![name].into_iter()) as BoxedStrIter].into_iter())
+}
+
+pub fn import_parser() -> impl Parser<char, Vec<Import>, Error = Simple<char>> {
+    recursive(|expr: Recursive<char, BoxedStrIterIter, Simple<char>>| {
+        name::modname_parser()
+            .padded()
+            .then_ignore(just("::"))
+            .repeated()
+            .then(
+                choice((
+                    expr.clone()
+                        .separated_by(just(','))
+                        .delimited_by(just('('), just(')'))
+                        .map(|v| Box::new(v.into_iter().flatten()) as BoxedStrIterIter),
+                    just("*").map(|s| init_table(s.to_string())),
+                    name::modname_parser().map(init_table)
+                )).padded()
+            ).map(|(pre, post)| {
+                Box::new(post.map(move |el| {
+                    Box::new(pre.clone().into_iter().chain(el)) as BoxedStrIter
+                })) as BoxedStrIterIter
+            })
+    }).padded().map(|paths| {
+        paths.filter_map(|namespaces| {
+            let mut path: Vec<String> = namespaces.collect();
+            match path.pop()?.as_str() {
+                "*" => Some(Import::All(path)),
+                name => Some(Import::Name(path, name.to_owned()))
+            }
+        }).collect()
+    })
+}
\ No newline at end of file
diff --git a/src/parse/misc.rs b/src/parse/misc.rs
new file mode 100644
index 0000000..fbe905d
--- /dev/null
+++ b/src/parse/misc.rs
@@ -0,0 +1,7 @@
+pub use chumsky::{self, prelude::*, Parser};
+
+pub fn comment_parser() -> impl Parser<char, String, Error = Simple<char>> {
+    any().repeated().delimited_by(just("--["), just("]--")).or(
+        any().repeated().delimited_by(just("--"), just("\n"))
+    ).map(|vc| vc.iter().collect()).padded()
+}
diff --git a/src/parse/mod.rs b/src/parse/mod.rs
new file mode 100644
index 0000000..1d7b7f7
--- /dev/null
+++ b/src/parse/mod.rs
@@ -0,0 +1,9 @@
+mod expression;
+mod string;
+mod number;
+mod misc;
+mod import;
+mod name;
+mod substitution;
+
+pub use expression::expression_parser;
diff --git a/src/parse/name.rs b/src/parse/name.rs
new file mode 100644
index 0000000..c8dfa67
--- /dev/null
+++ b/src/parse/name.rs
@@ -0,0 +1,28 @@
+use chumsky::{self, prelude::*, Parser};
+
+fn op_parser_recur<'a, 'b>(ops: &'a [String]) -> BoxedParser<'b, char, String, Simple<char>> {
+    if ops.len() == 1 { just(ops[0].clone()).boxed() }
+    else { just(ops[0].clone()).or(op_parser_recur(&ops[1..])).boxed() }
+}
+
+fn op_parser(ops: &[String]) -> BoxedParser<char, String, Simple<char>> {
+    let mut sorted_ops = ops.to_vec();
+    sorted_ops.sort_by(|a, b| b.len().cmp(&a.len()));
+    op_parser_recur(&sorted_ops)
+}
+
+pub fn modname_parser() -> impl Parser<char, String, Error = Simple<char>> {
+    let not_name_char: Vec<char> = vec![':', '\\', '"', '\'', '(', ')', '.'];
+    filter(move |c| !not_name_char.contains(c) && !c.is_whitespace())
+        .repeated().at_least(1)
+        .collect()
+}
+
+pub fn name_parser<'a>(ops: &'a [String]) -> impl Parser<char, String, Error = Simple<char>> + 'a {
+    choice((
+        op_parser(ops), // First try to parse a known operator
+        text::ident(), // Failing that, parse plain text
+        // Finally parse everything until tne next terminal as a new operator
+        modname_parser()
+    )).padded()
+}
\ No newline at end of file
diff --git a/src/parse/number.rs b/src/parse/number.rs
new file mode 100644
index 0000000..dde4e54
--- /dev/null
+++ b/src/parse/number.rs
@@ -0,0 +1,88 @@
+use chumsky::{self, prelude::*, Parser};
+
+fn assert_not_digit(base: u32, c: char) {
+    if base > (10 + (c as u32 - 'a' as u32)) {
+        panic!("The character '{}' is a digit in base ({})", c, base)
+    }
+}
+
+fn separated_digits_parser(base: u32) -> impl Parser<char, String, Error = Simple<char>> {
+    just('_')
+        .ignore_then(text::digits(base))
+        .repeated()
+        .map(|sv| sv.iter().map(|s| s.chars()).flatten().collect())
+}
+
+fn uint_parser(base: u32) -> impl Parser<char, u64, Error = Simple<char>> {
+    text::int(base)
+        .then(separated_digits_parser(base))
+        .map(move |(s1, s2): (String, String)| {
+            u64::from_str_radix(&(s1 + &s2), base).unwrap()
+        })
+}
+
+fn pow_parser() -> impl Parser<char, i32, Error = Simple<char>> {
+    return choice((
+        just('p')
+            .ignore_then(text::int(10))
+            .map(|s: String| s.parse().unwrap()),
+        just("p-")
+            .ignore_then(text::int(10))
+            .map(|s: String| -s.parse::<i32>().unwrap()),
+    )).or_else(|_| Ok(0))
+}
+
+fn nat2u(base: u64) -> impl Fn((u64, i32),) -> u64 {
+    return move |(val, exp)| {
+        if exp == 0 {val}
+        else {val * base.checked_pow(exp.try_into().unwrap()).unwrap()}
+    };
+}
+
+fn nat2f(base: u64) -> impl Fn((f64, i32),) -> f64 {
+    return move |(val, exp)| {
+        if exp == 0 {val}
+        else {val * (base as f64).powf(exp.try_into().unwrap())}
+    }
+}
+
+fn pow_uint_parser(base: u32) -> impl Parser<char, u64, Error = Simple<char>> {
+    assert_not_digit(base, 'p');
+    uint_parser(base).then(pow_parser()).map(nat2u(base.into()))
+}
+
+pub fn int_parser() -> impl Parser<char, u64, Error = Simple<char>> {
+    choice((
+        just("0b").ignore_then(pow_uint_parser(2)),
+        just("0x").ignore_then(pow_uint_parser(16)),
+        just('0').ignore_then(pow_uint_parser(8)),
+        pow_uint_parser(10), // Dec has no prefix
+    ))
+}
+
+fn dotted_parser(base: u32) -> impl Parser<char, f64, Error = Simple<char>> {
+    uint_parser(base)
+    .then_ignore(just('.'))
+    .then(
+        text::digits(base).then(separated_digits_parser(base))
+    ).map(move |(wh, (frac1, frac2))| {
+        let frac = frac1 + &frac2;
+        let frac_num = u64::from_str_radix(&frac, base).unwrap() as f64;
+        let dexp = base.pow(frac.len().try_into().unwrap());
+        wh as f64 + (frac_num / dexp as f64)
+    })
+}
+
+fn pow_float_parser(base: u32) -> impl Parser<char, f64, Error = Simple<char>> {
+    assert_not_digit(base, 'p');
+    dotted_parser(base).then(pow_parser()).map(nat2f(base.into()))
+}
+
+pub fn float_parser() -> impl Parser<char, f64, Error = Simple<char>> {
+    choice((
+        just("0b").ignore_then(pow_float_parser(2)),
+        just("0x").ignore_then(pow_float_parser(16)),
+        just('0').ignore_then(pow_float_parser(8)),
+        pow_float_parser(10),
+    ))
+}
diff --git a/src/parse/string.rs b/src/parse/string.rs
new file mode 100644
index 0000000..b74014d
--- /dev/null
+++ b/src/parse/string.rs
@@ -0,0 +1,42 @@
+use chumsky::{self, prelude::*, Parser};
+
+fn text_parser(delim: char) -> impl Parser<char, char, Error = Simple<char>> {
+    let escape = just('\\').ignore_then(
+        just('\\')
+            .or(just('/'))
+            .or(just('"'))
+            .or(just('b').to('\x08'))
+            .or(just('f').to('\x0C'))
+            .or(just('n').to('\n'))
+            .or(just('r').to('\r'))
+            .or(just('t').to('\t'))
+            .or(just('u').ignore_then(
+                filter(|c: &char| c.is_digit(16))
+                    .repeated()
+                    .exactly(4)
+                    .collect::<String>()
+                    .validate(|digits, span, emit| {
+                        char::from_u32(u32::from_str_radix(&digits, 16).unwrap())
+                            .unwrap_or_else(|| {
+                                emit(Simple::custom(span, "invalid unicode character"));
+                                '\u{FFFD}' // unicode replacement character
+                            })
+                    }),
+            )),
+    );
+    filter(move |&c| c != '\\' && c != delim).or(escape)
+}
+
+pub fn char_parser() -> impl Parser<char, char, Error = Simple<char>> {
+    just('\'').ignore_then(text_parser('\'')).then_ignore(just('\''))
+}
+
+pub fn str_parser() -> impl Parser<char, String, Error = Simple<char>> {
+    just('"')
+    .ignore_then(
+        text_parser('"').map(Some)
+        .or(just("\\\n").map(|_| None))
+        .repeated()
+    ).then_ignore(just('"'))
+    .flatten().collect()
+}
\ No newline at end of file
diff --git a/src/parse/substitution.rs b/src/parse/substitution.rs
new file mode 100644
index 0000000..ccc60c8
--- /dev/null
+++ b/src/parse/substitution.rs
@@ -0,0 +1,21 @@
+use chumsky::{self, prelude::*, Parser};
+
+use super::{expression, number::float_parser};
+
+pub struct Substitution {
+    source: expression::Expr,
+    priority: f64,
+    target: expression::Expr
+}
+
+pub fn substitutionParser<'a>(
+    ops: &'a [String]
+) -> impl Parser<char, Substitution, Error = Simple<char>> + 'a {
+    expression::expression_parser(ops)
+        .then_ignore(just('='))
+        .then(
+            float_parser().then_ignore(just("=>"))
+            .or_not().map(|prio| prio.unwrap_or(0.0))
+        ).then(expression::expression_parser(ops))
+        .map(|((source, priority), target)| Substitution { source, priority, target })
+}