add error-format component

Cargo.toml

@@ -16,6 +16,7 @@ lox-parse = { path="components/lox-parse" }
 lox-lex = { path="components/lox-lex" }
 lox-compile = { path="components/lox-compile" }
 lox-execute = { path="components/lox-execute" }
+lox-error-format = { path="components/lox-error-format" }
 tracing = "0.1.37"
 tracing-subscriber = { version = "0.3.17", features = ["env-filter"] }
 clap = { version = "4.4.4", features = ["derive"] }

components/lox-error-format/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "lox-error-format"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+ariadne = "0.3.0"
+salsa = { path="../salsa" }
+lox-ir = { path="../lox-ir" }
+eyre = "0.6.8"

components/lox-error-format/src/format.rs

@@ -0,0 +1,115 @@
+use std::{collections::HashMap, io::Cursor};
+
+use ariadne::{Config, Label, Report, ReportKind, Source};
+use lox_ir::input_file::InputFile;
+
+/// Options for controlling error formatting when they are printed.
+#[derive(Clone, Copy)]
+pub struct FormatOptions {
+    /// Whether or not errors should use rich formatting with colors. This is generally turned on,
+    /// except in tests, where the escape codes obscure the error messages.
+    with_color: bool,
+}
+
+impl FormatOptions {
+    pub fn no_color() -> Self {
+        Self { with_color: false }
+    }
+}
+
+const DEFAULT_FORMATTING: FormatOptions = FormatOptions { with_color: true };
+
+pub fn print_diagnostic(
+    db: &dyn crate::Db,
+    diagnostic: &lox_ir::diagnostic::Diagnostic,
+) -> eyre::Result<()> {
+    Ok(ariadne_diagnostic(db, diagnostic, DEFAULT_FORMATTING)?.print(SourceCache::new(db))?)
+}
+
+pub fn format_diagnostics(
+    db: &dyn crate::Db,
+    diagnostics: &[lox_ir::diagnostic::Diagnostic],
+) -> eyre::Result<String> {
+    format_diagnostics_with_options(db, diagnostics, DEFAULT_FORMATTING)
+}
+
+pub fn format_diagnostics_with_options(
+    db: &dyn crate::Db,
+    diagnostics: &[lox_ir::diagnostic::Diagnostic],
+    options: FormatOptions,
+) -> eyre::Result<String> {
+    let mut output = Vec::new();
+    let mut cursor = Cursor::new(&mut output);
+    let mut cache = SourceCache::new(db);
+    for diagnostic in diagnostics {
+        let ariadne = ariadne_diagnostic(db, diagnostic, options)?;
+        ariadne.write(&mut cache, &mut cursor)?;
+    }
+    Ok(String::from_utf8(output)?)
+}
+
+fn ariadne_diagnostic<'a>(
+    _db: &'a dyn crate::Db,
+    diagnostic: &'a lox_ir::diagnostic::Diagnostic,
+    options: FormatOptions,
+) -> eyre::Result<ariadne::Report<'a, ASpan>> {
+    let mut builder = Report::<ASpan>::build(
+        ReportKind::Error,
+        diagnostic.span.input_file,
+        diagnostic.span.start.into(),
+    )
+    .with_message(&diagnostic.message)
+    .with_config(Config::default().with_color(options.with_color));
+
+    for label in &diagnostic.labels {
+        builder = builder.with_label(Label::new(ASpan(label.span())).with_message(&label.message));
+    }
+
+    Ok(builder.finish())
+}
+
+struct SourceCache<'me> {
+    db: &'me dyn crate::Db,
+    map: HashMap<InputFile, Source>,
+}
+
+impl<'me> SourceCache<'me> {
+    pub fn new(db: &'me dyn crate::Db) -> Self {
+        Self {
+            db,
+            map: Default::default(),
+        }
+    }
+}
+
+impl ariadne::Cache<InputFile> for SourceCache<'_> {
+    fn fetch(&mut self, id: &InputFile) -> Result<&Source, Box<dyn std::fmt::Debug + '_>> {
+        Ok(self.map.entry(*id).or_insert_with(|| {
+            let source_text = id.source_text(self.db);
+            Source::from(source_text)
+        }))
+    }
+
+    fn display<'a>(&self, id: &'a InputFile) -> Option<Box<dyn std::fmt::Display + 'a>> {
+        let s = id.name(self.db).as_str(self.db).to_string();
+        Some(Box::new(s))
+    }
+}
+
+struct ASpan(lox_ir::span::FileSpan);
+
+impl ariadne::Span for ASpan {
+    type SourceId = InputFile;
+
+    fn source(&self) -> &Self::SourceId {
+        &self.0.input_file
+    }
+
+    fn start(&self) -> usize {
+        self.0.start.into()
+    }
+
+    fn end(&self) -> usize {
+        self.0.end.into()
+    }
+}

components/lox-error-format/src/lib.rs

@@ -0,0 +1,16 @@
+#![feature(trait_upcasting)]
+#![feature(try_blocks)]
+#![allow(incomplete_features)]
+
+mod format;
+
+#[salsa::jar(db = Db)]
+pub struct Jar();
+
+pub trait Db: salsa::DbWithJar<Jar> + lox_ir::Db {}
+impl<T> Db for T where T: salsa::DbWithJar<Jar> + lox_ir::Db {}
+
+pub use format::format_diagnostics;
+pub use format::format_diagnostics_with_options;
+pub use format::print_diagnostic;
+pub use format::FormatOptions;

components/lox-ir/src/input_file.rs

@@ -2,7 +2,7 @@ use crate::word::Word;
 
 #[salsa::input]
 pub struct InputFile {
-    name: Word,
+    pub name: Word,
 
     // the raw contents of the input file, as a string
     #[return_ref]

lox_tests/arithmetic/output

@@ -1,48 +1,28 @@
-Diagnostic {
-    severity: Error,
-    span: @7..@8,
-    message: "expected `;`",
-    labels: [
-        Label {
-            span: @7..@8,
-            message: "here",
-        },
-    ],
-    children: [],
-}
-Diagnostic {
-    severity: Error,
-    span: @18..@19,
-    message: "expected `;`",
-    labels: [
-        Label {
-            span: @18..@19,
-            message: "here",
-        },
-    ],
-    children: [],
-}
-Diagnostic {
-    severity: Error,
-    span: @29..@30,
-    message: "expected `;`",
-    labels: [
-        Label {
-            span: @29..@30,
-            message: "here",
-        },
-    ],
-    children: [],
-}
-Diagnostic {
-    severity: Error,
-    span: @38..@39,
-    message: "expected `;`",
-    labels: [
-        Label {
-            span: @38..@39,
-            message: "here",
-        },
-    ],
-    children: [],
-}
+Error: expected `;`
+   ╭─[/home/zhoufan/workspace/lox/lox_tests/arithmetic.lox:3:1]
+   │
+ 3 │ 1 + 2 * 3
+   │ ┬  
+   │ ╰── here
+───╯
+Error: expected `;`
+   ╭─[/home/zhoufan/workspace/lox/lox_tests/arithmetic.lox:5:1]
+   │
+ 5 │ 1 - 2 / 3
+   │ ┬  
+   │ ╰── here
+───╯
+Error: expected `;`
+   ╭─[/home/zhoufan/workspace/lox/lox_tests/arithmetic.lox:7:1]
+   │
+ 7 │ 1 + 2 * -3
+   │ ┬  
+   │ ╰── here
+───╯
+Error: expected `;`
+   ╭─[/home/zhoufan/workspace/lox/lox_tests/arithmetic.lox:7:10]
+   │
+ 7 │ 1 + 2 * -3
+   │          ┬  
+   │          ╰── here
+───╯

lox_tests/boolean/output

@@ -1,48 +1,28 @@
-Diagnostic {
-    severity: Error,
-    span: @5..@10,
-    message: "expected `;`",
-    labels: [
-        Label {
-            span: @5..@10,
-            message: "here",
-        },
-    ],
-    children: [],
-}
-Diagnostic {
-    severity: Error,
-    span: @11..@12,
-    message: "expected `;`",
-    labels: [
-        Label {
-            span: @11..@12,
-            message: "here",
-        },
-    ],
-    children: [],
-}
-Diagnostic {
-    severity: Error,
-    span: @17..@18,
-    message: "expected `;`",
-    labels: [
-        Label {
-            span: @17..@18,
-            message: "here",
-        },
-    ],
-    children: [],
-}
-Diagnostic {
-    severity: Error,
-    span: @18..@23,
-    message: "expected `;`",
-    labels: [
-        Label {
-            span: @18..@23,
-            message: "here",
-        },
-    ],
-    children: [],
-}
+Error: expected `;`
+   ╭─[/home/zhoufan/workspace/lox/lox_tests/boolean.lox:2:1]
+   │
+ 2 │ false
+   │ ──┬──  
+   │   ╰──── here
+───╯
+Error: expected `;`
+   ╭─[/home/zhoufan/workspace/lox/lox_tests/boolean.lox:3:1]
+   │
+ 3 │ !true
+   │ ┬  
+   │ ╰── here
+───╯
+Error: expected `;`
+   ╭─[/home/zhoufan/workspace/lox/lox_tests/boolean.lox:4:1]
+   │
+ 4 │ !false
+   │ ┬  
+   │ ╰── here
+───╯
+Error: expected `;`
+   ╭─[/home/zhoufan/workspace/lox/lox_tests/boolean.lox:4:2]
+   │
+ 4 │ !false
+   │  ──┬──  
+   │    ╰──── here
+───╯