add custom error type

src/main.rs

@@ -4,6 +4,7 @@ mod package;
 mod parser;
 mod rtlil;
 
+use ariadne::Source;
 use std::fs::File;
 use std::io::prelude::*;
 use std::path::PathBuf;
@@ -48,11 +49,9 @@ fn main() {
             if opt.debug {
                 println!("{err:#?}");
             }
-            /*
             parser::error::convert_error(input, err)
                 .eprint(Source::from(input.fragment()))
                 .unwrap();
-            */
         }
         Err(_) => (unreachable!()),
         Ok(res) => {

src/parser/error.rs

@@ -1,23 +1,124 @@
+use super::tokens::{TokenKind, TokenSpan};
 use super::{IErr, Span};
 use ariadne::{Label, Report, ReportKind};
-use nom_greedyerror::{GreedyErrorKind, Position};
+use nom::error::{ContextError, ParseError};
+use nom::InputTake;
 
-fn span_to_range(input: Span) -> std::ops::Range<usize> {
-    input.position()..(input.position() + input.len())
+#[derive(Debug)]
+pub struct Error<I> {
+    pub errors: Vec<(I, ErrorKind)>,
 }
 
-pub fn convert_error(_input: Span, e: IErr<Span>) -> Report {
-    let mut labels = Vec::new();
-    for err in e.errors {
-        let label = match err.1 {
-            GreedyErrorKind::Context(ctx) => {
-                Label::new(span_to_range(err.0)).with_message(format!("in {ctx}"))
+#[derive(Debug, Clone)]
+pub enum ErrorKind {
+    /// A static context string
+    Context(&'static str),
+    /// An expected character
+    Char(char),
+    /// An expected token
+    Token(TokenKind),
+    /// A list of valid tokens
+    Tokens(Vec<TokenKind>),
+    /// A nom error
+    Nom(nom::error::ErrorKind),
+}
+
+impl<I> ParseError<I> for Error<I>
+where
+    I: InputPos + std::fmt::Debug + Clone,
+{
+    fn from_error_kind(input: I, kind: nom::error::ErrorKind) -> Self {
+        Self {
+            errors: vec![(input, ErrorKind::Nom(kind))],
+        }
+    }
+
+    fn append(input: I, kind: nom::error::ErrorKind, mut other: Self) -> Self {
+        other.errors.push((input, ErrorKind::Nom(kind)));
+        other
+    }
+
+    fn from_char(input: I, c: char) -> Self {
+        Self {
+            errors: vec![(input, ErrorKind::Char(c))],
+        }
+    }
+
+    fn or(mut self, mut other: Self) -> Self {
+        let self_first = self.errors.first();
+        let other_first = other.errors.first();
+        match (self_first, other_first) {
+            (Some((is, ErrorKind::Token(s))), Some((io, ErrorKind::Token(o)))) => {
+                let combined_kind = ErrorKind::Tokens(vec![s.clone(), o.clone()]);
+                other.errors[0] = (io.clone(), combined_kind);
+                other
+            }
+            _ => {
+                other.errors.extend_from_slice(&self.errors[..]);
+                other
+            }
+        }
+    }
+}
+
+impl<I> ContextError<I> for Error<I> {
+    fn add_context(input: I, ctx: &'static str, mut other: Self) -> Self {
+        other.errors.push((input, ErrorKind::Context(ctx)));
+        other
+    }
+}
+
+impl<I> Error<I> {
+    pub fn from_tokenkind(input: I, kind: TokenKind) -> Self {
+        Self {
+            errors: vec![(input, ErrorKind::Token(kind))],
+        }
+    }
+}
+
+pub trait InputPos {
+    fn position(&self) -> usize;
+}
+
+impl InputPos for Span<'_> {
+    fn position(&self) -> usize {
+        self.location_offset()
+    }
+}
+
+fn tokspan_to_range(input: TokenSpan) -> std::ops::Range<usize> {
+    let first = input.first().unwrap().span().position();
+    let last_span = input.last().unwrap().span();
+    let last = last_span.position() + last_span.len();
+    first..last
+}
+
+fn label_tokspan(input: TokenSpan) -> Label {
+    Label::new(tokspan_to_range(input))
+}
+
+pub fn convert_error(_input: Span, e: IErr<TokenSpan>) -> Report {
+    let mut labels = Vec::new();
+    let mut colors = ariadne::ColorGenerator::new();
+    for (input, err) in e.errors {
+        let label = match err {
+            ErrorKind::Context(ctx) => label_tokspan(input).with_message(format!("in {ctx}")),
+            ErrorKind::Char(c) => label_tokspan(input).with_message(format!("expected {c:?}")),
+            ErrorKind::Nom(kind) => {
+                label_tokspan(input).with_message(format!("nom error {kind:?}"))
+            }
+            ErrorKind::Token(t) => {
+                let next = input.first().unwrap().kind();
+                let msg = format!("expected {t:?} found {next:?}");
+                label_tokspan(input.take(1)).with_message(msg)
+            }
+            ErrorKind::Tokens(ts) => {
+                let next = input.first().unwrap().kind();
+                let msg = format!("expected one of {ts:?} found {next:?}");
+                label_tokspan(input.take(1)).with_message(msg)
             }
-            GreedyErrorKind::Char(c) => Label::new(err.0.position()..err.0.position())
-                .with_message(format!("expected {c:?}")),
-            GreedyErrorKind::Nom(kind) => Label::new(err.0.position()..err.0.position())
-                .with_message(format!("nom error {kind:?}")),
         };
+        let label = label.with_color(colors.next());
         labels.push(label);
     }
     let mut rep = Report::build(ReportKind::Error, (), 0).with_message("Parse Error");

src/parser/mod.rs

@@ -15,13 +15,12 @@ use nom::{
     multi::{many0, separated_list0},
     sequence::{delimited, pair, preceded, separated_pair, tuple},
 };
-use nom_greedyerror::GreedyError;
 use nom_locate::LocatedSpan;
 
 // custom span type for nom_locate
 pub type Span<'a> = LocatedSpan<&'a str>;
 
-pub type IErr<I> = GreedyError<I, ErrorKind>;
+pub type IErr<I> = error::Error<I>;
 // custom IResult type for VerboseError
 pub type IResult<I, O, E = IErr<I>> = nom::IResult<I, O, E>;
 

src/parser/module.rs

@@ -1,6 +1,6 @@
 use nom::{
     branch::alt,
-    combinator::map,
+    combinator::{cut, map},
     error::context,
     multi::{many0, separated_list0},
     sequence::{delimited, preceded, tuple},
@@ -52,7 +52,11 @@ fn inputs_list(input: TokenSpan) -> IResult<TokenSpan, Vec<PortDecl>> {
 fn assign_item(input: TokenSpan) -> IResult<TokenSpan, Assign> {
     context(
         "assignment",
-        delimited(token(tk::Assign), assign_statement, token(tk::Semicolon)),
+        delimited(
+            token(tk::Assign),
+            cut(assign_statement),
+            cut(token(tk::Semicolon)),
+        ),
     )(input)
 }
 
@@ -64,23 +68,22 @@ fn module_item(input: TokenSpan) -> IResult<TokenSpan, ModuleItem> {
 }
 
 pub fn module(input: TokenSpan) -> IResult<TokenSpan, Module> {
-    context(
-        "module",
     map(
-            tuple((
+        preceded(
             token(tk::Module),
+            cut(tuple((
                 token(tk::Ident),
                 delimited(token(tk::LParen), inputs_list, token(tk::RParen)),
                 preceded(token(tk::RArrow), typename),
                 delimited(token(tk::LBrace), many0(module_item), token(tk::RBrace)),
-            )),
-            |(_, name, inputs, _ret, items)| Module {
+            ))),
+        ),
+        |(name, inputs, _ret, items)| Module {
             // TODO: bring back returns
             name: name.span(),
             ports: inputs,
             items,
         },
-        ),
     )(input)
 }
 

src/parser/tokens.rs

@@ -1,6 +1,7 @@
 //! convert text into a token stream
 
 use super::{
+    error::{Error, InputPos},
     literals::{identifier, ws0},
     IResult, Span,
 };
@@ -9,7 +10,6 @@ use nom::{
     bytes::complete::tag,
     character::complete::{anychar, digit1},
     combinator::{consumed, map, recognize},
-    error::ParseError,
     multi::many0,
 };
 use std::fmt;
@@ -40,9 +40,12 @@ impl<'a> Token<'a> {
     pub fn span(&self) -> Span {
         self.span
     }
+    pub fn kind(&self) -> TokenKind {
+        self.kind
+    }
 }
 
-#[derive(Debug, PartialEq, Clone)]
+#[derive(Debug, PartialEq, Copy, Clone)]
 pub enum TokenKind {
     // no whitespace, for now
     // no token trees either, for now
@@ -92,6 +95,12 @@ impl<'a> TokenSpan<'a> {
     pub fn with_pos(rest: &'a [Token<'a>], pos: usize) -> Self {
         Self { rest, pos }
     }
+    pub fn first(&self) -> Option<&Token> {
+        self.rest.first()
+    }
+    pub fn last(&self) -> Option<&Token> {
+        self.rest.last()
+    }
 }
 
 impl nom::InputTake for TokenSpan<'_> {
@@ -114,30 +123,22 @@ impl nom::InputLength for TokenSpan<'_> {
     }
 }
 
-impl nom_greedyerror::Position for TokenSpan<'_> {
+impl InputPos for TokenSpan<'_> {
     fn position(&self) -> usize {
         self.pos
     }
 }
 
 /// combinator that matches a token kind
-pub fn token<'a, E>(
-    kind: TokenKind,
-) -> impl FnMut(TokenSpan<'a>) -> nom::IResult<TokenSpan, &Token, E>
-where
-    E: ParseError<TokenSpan<'a>>,
-{
+pub fn token<'a>(kind: TokenKind) -> impl FnMut(TokenSpan<'a>) -> IResult<TokenSpan, &Token> {
     move |input: TokenSpan| {
         let next = &input.rest[0];
-        if next.kind == kind.clone() {
+        let kind = kind.clone();
+        if next.kind == kind {
             let rest = TokenSpan::with_pos(&input.rest[1..], input.pos + 1);
             Ok((rest, next))
         } else {
-            Err(nom::Err::Error(E::from_error_kind(
-                input,
-                // TODO: Proper errors here
-                nom::error::ErrorKind::Tag,
-            )))
+            Err(nom::Err::Error(Error::from_tokenkind(input, kind)))
         }
     }
 }