Add first steps of AutoChomp

10 files changed, 199 insertions, 14 deletions

diff --git a/Cargo.toml b/Cargo.toml
index f25ec0c..ca41e36 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,18 +5,15 @@ authors = ["Greg Brown <gmb60@cam.ac.uk>"]
 edition = "2018"
 
 [workspace]
-members = ["chewed"]
+members = ["autochomp", "chewed"]
 
 [dependencies]
-quote = "1.0.7"
+quote = "1"
 
 [dependencies.proc-macro2]
-version = "1.0.24"
+version = "1"
 features = ["span-locations"]
 
 [dependencies.syn]
-version = "1.0.48"
+version = "1"
 features = ["extra-traits"]
-
-[dev-dependencies]
-chewed = {path = "chewed"}
diff --git a/autochomp/Cargo.toml b/autochomp/Cargo.toml
new file mode 100644
index 0000000..4e20c49
--- /dev/null
+++ b/autochomp/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "autochomp"
+version = "0.1.0"
+authors = ["Greg Brown <gmb60@cam.ac.uk>"]
+edition = "2018"
+
+[build-dependencies]
+chomp = {path = ".."}
+
+[build-dependencies.syn]
+version = "1"
+features = ["extra-traits"]
+
+[dependencies]
+chewed = {path = "../chewed"}
diff --git a/autochomp/build.rs b/autochomp/build.rs
new file mode 100644
index 0000000..952d49c
--- /dev/null
+++ b/autochomp/build.rs
@@ -0,0 +1,73 @@
+use std::{
+    env,
+    error::Error,
+    fmt::Display,
+    fs,
+    io::{Read, Write},
+    path::Path,
+    process::exit,
+};
+
+use chomp::{
+    chomp::{
+        check::{InlineCall, TypeCheck},
+        context::Context,
+        visit::Visitable,
+    },
+    lower::{rust::RustBackend, Backend, GenerateCode},
+    nibble::cst::File,
+};
+
+const PATH: &str = "src/nibble.nb";
+
+#[derive(Debug)]
+struct UndecVar;
+
+impl Display for UndecVar {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "Undeclared variable somewhere.")
+    }
+}
+impl Error for UndecVar {}
+
+fn main() {
+    println!("cargo:rerun-if-changed={}", PATH);
+
+    let out_dir = env::var("OUT_DIR").unwrap();
+
+    let mut input = String::new();
+    let res = fs::File::open(PATH)
+        .map_err(|e| Box::new(e) as Box<dyn Error>)
+        .and_then(|mut file| file.read_to_string(&mut input).map_err(|e| Box::new(e) as Box<dyn Error>))
+        .and_then(|_| syn::parse_str(&input).map_err(|e| Box::new(e) as Box<dyn Error>))
+        .and_then(|nibble: File| nibble.convert().ok_or(Box::new(UndecVar) as Box<dyn Error>))
+        .and_then(|(funs, goal)| {
+            funs.into_iter()
+                .try_rfold(goal, |goal, function| {
+                    goal.fold(&mut InlineCall::new(function))
+                })
+                .map_err(|e| Box::new(e) as Box<dyn Error>)
+        })
+        .and_then(|term| {
+            let mut context = Context::default();
+            term.fold(&mut TypeCheck {
+                context: &mut context,
+            })
+            .map_err(|e| Box::new(e) as Box<dyn Error>)
+        })
+        .map(|typed| {
+            let mut backend = RustBackend::default();
+            let id = typed.gen(&mut backend);
+            backend.emit_code(id)
+        })
+        .and_then(|code| {
+            fs::File::create(Path::new(&out_dir).join("nibble.rs"))
+                .and_then(|mut f| write!(f, "{}", code))
+                .map_err(|e| Box::new(e) as Box<dyn Error>)
+        });
+
+    if let Err(e) = res {
+        eprintln!("{}", e);
+        exit(1)
+    }
+}
diff --git a/autochomp/src/main.rs b/autochomp/src/main.rs
new file mode 100644
index 0000000..400cc2d
--- /dev/null
+++ b/autochomp/src/main.rs
@@ -0,0 +1,23 @@
+use std::{error::Error, io::{self, Read, Write}, process::exit};
+
+use chewed::Parse;
+
+mod nibble {
+    include!(concat!(env!("OUT_DIR"), "/nibble.rs"));
+}
+
+fn main() {
+    let mut input = String::new();
+    let res = io::stdin()
+        .read_to_string(&mut input)
+        .map_err(|e| Box::new(e) as Box<dyn Error>)
+        .and_then(|_| nibble::Ast::parse(input.chars().peekable()).map_err(|e| Box::new(e) as Box<dyn Error>))
+        .and_then(|ast| {
+            write!(io::stdout(), "{:?}", ast).map_err(|e| Box::new(e) as Box<dyn Error>)
+        });
+
+    if let Err(e) = res {
+        eprintln!("{}", e);
+        exit(1)
+    }
+}
diff --git a/autochomp/src/nibble.nb b/autochomp/src/nibble.nb
new file mode 100644
index 0000000..fed3d46
--- /dev/null
+++ b/autochomp/src/nibble.nb
@@ -0,0 +1,67 @@
+let opt(x) = _ | x;
+let plus(x) = [plus](x . opt(plus));
+let star(x) = opt(plus(x));
+let star_(base, step) = [rec](base | step . rec);
+
+let Pattern_Whitespace = "\t"|"\n"|"\x0B"|"\x0c"|"\r"|" "|"\u{85}"|"\u{200e}"|"\u{200f}"|"\u{2028}"|"\u{2029}";
+
+let digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9";
+let oct_digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7";
+let hex_digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" |
+                "a" | "b" | "c" | "d" | "e" | "f" |
+                "A" | "B" | "C" | "D" | "E" | "F" ;
+
+let XID_Start =
+    "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" |
+    "i" | "j" | "k" | "l" | "m" | "n" | "o" | "p" |
+    "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x" |
+    "y" | "z" |
+    "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" |
+    "I" | "J" | "K" | "L" | "M" | "N" | "O" | "P" |
+    "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" |
+    "Y" | "Z" ;
+let XID_Continue =
+    XID_Start | "_" | "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
+
+let literal_char =
+    " " | "!"       | "#" | "$" | "%" | "&" | "'" |
+    "(" | ")" | "*" | "+" | "," | "-" | "." | "/" |
+    "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" |
+    "8" | "9" | ":" | ";" | "<" | "=" | ">" | "?" |
+    "@" | "A" | "B" | "C" | "D" | "E" | "F" | "G" |
+    "H" | "I" | "J" | "K" | "L" | "M" | "N" | "O" |
+    "P" | "Q" | "R" | "S" | "T" | "U" | "V" | "W" |
+    "X" | "Y" | "Z" | "["       | "]" | "^" | "_" |
+    "`" | "a" | "b" | "c" | "d" | "e" | "f" | "g" |
+    "h" | "i" | "j" | "k" | "l" | "m" | "n" | "o" |
+    "p" | "q" | "r" | "s" | "t" | "u" | "v" | "w" |
+    "x" | "y" | "z" | "{" | "|" | "}" | "~" |
+    "\\" . ("\"" | "'" | "n" | "r" | "t" | "\\" | "0" |
+            "x" . oct_digit . hex_digit |
+            "u{" . hex_digit . opt(hex_digit . opt(hex_digit . opt(hex_digit . opt(hex_digit . opt(hex_digit))))) . "}");
+
+let ws = plus(Pattern_Whitespace);
+
+let punctuated(x, p) = [rec](x . opt(p . opt(ws) . opt(rec)));
+let list(x) = "(" . opt(ws) . punctuated(x, ",") . ")";
+
+let epsilon = "_";
+let ident = XID_Start . star(XID_Continue);
+let literal = "\"" . plus(literal_char) . "\"";
+let parens(expr) = "(" . opt(ws) . expr . ")";
+let fix(expr) = "[" . opt(ws) . ident . opt(ws) . "]" . opt(ws) . parens(expr);
+
+let term(expr) =
+      epsilon . opt(ws)
+    | literal . opt(ws)
+    | parens(expr) . opt(ws)
+    | fix(expr) . opt(ws)
+    | ident . opt(ws) . opt(list(expr) . opt(ws))
+    ;
+
+let seq(expr) = punctuated(term(expr), ".");
+let alt(expr) = punctuated(seq(expr), "|");
+let expr = [expr](alt(expr));
+let let = "let" . ws . ident . opt(ws) . opt(list(ident . opt(ws)) . opt(ws)) . "=" . opt(ws) . expr . ";";
+let goal = "match" . ws . expr . ";";
+match star_(goal, let);
diff --git a/chewed/src/error.rs b/chewed/src/error.rs
index cb2cc4b..420a376 100644
--- a/chewed/src/error.rs
+++ b/chewed/src/error.rs
@@ -11,7 +11,7 @@ impl fmt::Display for TakeError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Self::BadBranch(got, expected) => {
-                write!(f, "Unexpected character {:?}.", got)?;
+                write!(f, "Unexpected character {:?}. ", got)?;
 
                 if expected.is_empty() {
                     write!(f, "Expected end of input.")
@@ -51,6 +51,8 @@ impl fmt::Display for ParseError {
     }
 }
 
+impl Error for ParseError {}
+
 impl From<TakeError> for ParseError {
     fn from(e: TakeError) -> Self {
         Self::TakeError(e)
diff --git a/chewed/src/parse.rs b/chewed/src/parse.rs
index 0687ea5..f6bbd66 100644
--- a/chewed/src/parse.rs
+++ b/chewed/src/parse.rs
@@ -1,3 +1,5 @@
+use std::iter::Peekable;
+
 use super::error::{ParseError, TakeError};
 
 pub trait Parser: Iterator<Item = char> {
@@ -37,6 +39,12 @@ pub trait Parser: Iterator<Item = char> {
     }
 }
 
+impl<I: Iterator<Item = char>> Parser for Peekable<I> {
+    fn peek(&mut self) -> Option<char> {
+        Peekable::peek(self).copied()
+    }
+}
+
 pub trait Parse: Sized {
     fn take<P: Parser + ?Sized>(input: &mut P) -> Result<Self, TakeError>;
 
diff --git a/examples/autochomp/main.rs b/examples/autochomp/main.rs
deleted file mode 100644
index afa489f..0000000
--- a/examples/autochomp/main.rs
+++ /dev/null
@@ -1,3 +0,0 @@
-pub fn main() {
-    todo!("Create AutoChomp")
-}
diff --git a/src/chomp/error.rs b/src/chomp/error.rs
index 6733d06..d0a3cc8 100644
--- a/src/chomp/error.rs
+++ b/src/chomp/error.rs
@@ -291,7 +291,7 @@ impl Display for FixError {
         let start = self.0.span().unwrap_or_else(Span::call_site).start();
         write!(
             f,
-            "\n({}:{}) assuming `{}' has type {:?}.",
+            "\n{}:{}: assuming `{}' has type {:?}.",
             start.line,
             start.column,
             self.0.arg(),
diff --git a/src/lower/rust.rs b/src/lower/rust.rs
index c236bdd..fab040b 100644
--- a/src/lower/rust.rs
+++ b/src/lower/rust.rs
@@ -66,6 +66,7 @@ impl Backend for RustBackend {
             );
             let tokens = quote! {
                 #[doc=#doc_name]
+                #[derive(Clone, Debug, Eq, Hash, PartialEq)]
                 pub struct #name;
 
                 impl Parse for #name {
@@ -128,6 +129,7 @@ impl Backend for RustBackend {
             let right_ty = self.data[right].0.clone();
             let name = format_ident!("Alt{}", id);
             let mut tokens = quote! {
+                #[derive(Clone, Debug, Eq, Hash, PartialEq)]
                 pub enum #name {
                     Left(#left_ty),
                     Right(#right_ty),
@@ -170,7 +172,7 @@ impl Backend for RustBackend {
                             match input.peek().ok_or(TakeError::EndOfStream)? {
                                 #(#iter_left)|* => input.take().map(Self::Left),
                                 #(#iter_right)|* => input.take().map(Self::Right),
-                                c => input.error(TakeError::BadBranch(c, &[#(#iter_first),*]))
+                                c => Err(TakeError::BadBranch(c, &[#(#iter_first),*]))
                             }
                         }
                     }
@@ -204,11 +206,12 @@ impl Backend for RustBackend {
             let inner = inner.gen(self);
             let inner_ty = self.data[inner].0.clone();
             let tokens = quote! {
+                #[derive(Clone, Debug, Eq, Hash, PartialEq)]
                 pub struct #name(#inner_ty);
 
                 impl Parse for #name {
                     fn take<P: Parser + ?Sized>(input: &mut P) -> Result<Self, TakeError> {
-                        input.parse().map(Self)
+                        input.take().map(Self)
                     }
                 }
             };