feat: starting to get pretty error messages

Cargo.lock

@@ -78,6 +78,7 @@ dependencies = [
  "internment",
  "miette",
  "pretty_assertions",
+ "thiserror",
  "vec1",
 ]
 

crates/cli/src/error.rs

@@ -1,18 +1,80 @@
-use std::{io, path::PathBuf};
+use std::{
+    fmt::{Debug, Display},
+    io,
+    path::PathBuf,
+};
 
 use aiken_lang::error::ParseError;
+use miette::{EyreContext, LabeledSpan, MietteHandlerOpts, RgbColors, SourceCode};
 
 #[allow(dead_code)]
-#[derive(Debug, thiserror::Error, miette::Diagnostic)]
+#[derive(thiserror::Error)]
 pub enum Error {
     #[error("file operation failed")]
     FileIo { path: PathBuf, error: io::Error },
-    #[error("failed to parse Aiken source code")]
+    #[error("failed to parse")]
     Parse {
         path: PathBuf,
+
         src: String,
+
+        #[source]
         error: Box<ParseError>,
     },
-    #[error("list of errors")]
+    /// Useful for returning many [`Error::Parse`] at once
+    #[error("a list of errors")]
     List(Vec<Self>),
 }
+
+impl Debug for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let miette_handler = MietteHandlerOpts::new()
+            // For better support of terminal themes use the ANSI coloring
+            .rgb_colors(RgbColors::Never)
+            // If ansi support is disabled in the config disable the eye-candy
+            .color(true)
+            .unicode(true)
+            .terminal_links(true)
+            .build();
+
+        // Ignore error to prevent format! panics. This can happen if span points at some
+        // inaccessible location, for example by calling `report_error()` with wrong working set.
+        let _ = miette_handler.debug(self, f);
+
+        Ok(())
+    }
+}
+
+impl miette::Diagnostic for Error {
+    fn code<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
+        match self {
+            Error::Parse { .. } => Some(Box::new("aiken::parser".to_string())),
+            Error::FileIo { .. } => None,
+            Error::List(_) => None,
+        }
+    }
+
+    fn source_code(&self) -> Option<&dyn SourceCode> {
+        match self {
+            Error::Parse { src, .. } => Some(src),
+            Error::FileIo { .. } => None,
+            Error::List(_) => None,
+        }
+    }
+
+    fn labels(&self) -> Option<Box<dyn Iterator<Item = LabeledSpan> + '_>> {
+        match self {
+            Error::Parse { error, .. } => error.labels(),
+            Error::FileIo { .. } => None,
+            Error::List(_) => None,
+        }
+    }
+
+    fn help<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
+        match self {
+            Error::Parse { error, .. } => error.kind.help(),
+            Error::FileIo { .. } => None,
+            Error::List(_) => None,
+        }
+    }
+}

crates/cli/src/main.rs

@@ -16,13 +16,15 @@ use uplc::{
     },
 };
 
-use aiken::{config::Config, project::Project};
+use aiken::{config::Config, error, project::Project};
 
 mod args;
 
 use args::{Args, TxCommand, UplcCommand};
 
 fn main() -> miette::Result<()> {
+    miette::set_panic_hook();
+
     let args = Args::default();
 
     match args {
@@ -47,7 +49,16 @@ fn main() -> miette::Result<()> {
 
             let mut project = Project::new(config, project_path);
 
-            project.build()?;
+            if let Err(err) = project.build() {
+                match err {
+                    error::Error::List(errors) => {
+                        for error in errors {
+                            eprintln!("Error: {:?}", error)
+                        }
+                    }
+                    rest => Err(rest)?,
+                }
+            };
         }
 
         Args::Dev => {

crates/cli/src/project.rs

@@ -17,6 +17,7 @@ pub struct Source {
 }
 
 #[derive(Debug)]
+#[allow(dead_code)]
 struct ParsedModule {
     path: PathBuf,
     name: String,

crates/lang/Cargo.toml

@@ -14,6 +14,7 @@ authors = ["Lucas Rosa <x@rvcas.dev>", "Kasey White <kwhitemsg@gmail.com>"]
 chumsky = "0.8.0"
 internment = "0.7.0"
 miette = "5.2.0"
+thiserror = "1.0.37"
 vec1 = "1.8.0"
 
 [dev-dependencies]

crates/lang/src/ast.rs

@@ -498,6 +498,12 @@ pub struct Span {
     pub end: usize,
 }
 
+impl From<Span> for miette::SourceSpan {
+    fn from(span: Span) -> Self {
+        Self::new(span.start.into(), span.end.into())
+    }
+}
+
 impl Span {
     pub fn empty() -> Self {
         use chumsky::Span;

crates/lang/src/error.rs

@@ -1,11 +1,15 @@
 use std::{collections::HashSet, fmt};
 
+use miette::Diagnostic;
+
 use crate::{ast::Span, token::Token};
 
-#[derive(Debug)]
+#[derive(Debug, Diagnostic, thiserror::Error)]
+#[error("{}", .kind)]
 pub struct ParseError {
-    kind: ErrorKind,
+    pub kind: ErrorKind,
-    span: Span,
+    #[label]
+    pub span: Span,
     #[allow(dead_code)]
     while_parsing: Option<(Span, &'static str)>,
     expected: HashSet<Pattern>,
@@ -63,19 +67,24 @@ impl<T: Into<Pattern>> chumsky::Error<T> for ParseError {
     }
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq, Eq, Diagnostic, thiserror::Error)]
 pub enum ErrorKind {
+    #[error("unexpected end")]
     UnexpectedEnd,
+    #[error("unexpected {0}")]
+    #[diagnostic(help("try removing it"))]
     Unexpected(Pattern),
+    #[error("unclosed {start}")]
     Unclosed {
         start: Pattern,
         before_span: Span,
         before: Option<Pattern>,
     },
+    #[error("no end branch")]
     NoEndBranch,
 }
 
-#[derive(Debug, PartialEq, Eq, Hash)]
+#[derive(Debug, PartialEq, Eq, Hash, Diagnostic, thiserror::Error)]
 pub enum Pattern {
     Char(char),
     Token(Token),

examples/sample/scripts/swap.ak

@@ -5,7 +5,7 @@ pub type Datum {
 }
 
 pub type Redeemer {
-  Buy
+  Buy,
   Sell
 }