Add Context struct for locating compiler messages

src/error.rs

@@ -1,8 +1,58 @@
-use std::{error::Error, fmt::Display, ops::Range};
+use std::{cell::RefCell, error::Error, fmt::Display, ops::Range, rc::Rc};
 
 use crate::world::World;
 
-pub type CompileResult = Result<Vec<CompileMessage>, Vec<CompileMessage>>;
+#[derive(Clone, Default)]
+pub struct Context {
+    messages: Rc<RefCell<Vec<CompileMessage>>>,
+    location: Location,
+}
+
+impl Context {
+    pub fn with_file_path(&self, s: &str) -> Self {
+        let mut result = self.clone();
+        result.location.file_path = Some(s.into());
+        result
+    }
+
+    pub fn with_board(&self, board: usize) -> Self {
+        let mut result = self.clone();
+        result.location.board = Some(board);
+        result
+    }
+
+    pub fn with_stat(&self, stat: usize) -> Self {
+        let mut result = self.clone();
+        result.location.stat = Some(stat);
+        result
+    }
+
+    pub fn with_span(&self, span: Range<usize>) -> Self {
+        let mut result = self.clone();
+        result.location.span = Some(span);
+        result
+    }
+
+    pub fn error(&self, message: &str) {
+        self.messages.borrow_mut().push(CompileMessage {
+            level: Level::Error,
+            message: message.into(),
+            location: self.location.clone(),
+        });
+    }
+
+    pub fn warning(&self, message: &str) {
+        self.messages.borrow_mut().push(CompileMessage {
+            level: Level::Warning,
+            message: message.into(),
+            location: self.location.clone(),
+        });
+    }
+
+    pub fn into_messages(self) -> Vec<CompileMessage> {
+        self.messages.take()
+    }
+}
 
 #[derive(Debug)]
 pub struct CompileMessage {
@@ -17,7 +67,7 @@ pub enum Level {
     Warning,
 }
 
-#[derive(Debug)]
+#[derive(Clone, Debug, Default)]
 pub struct Location {
     pub file_path: Option<String>,
     pub board: Option<usize>,
@@ -28,8 +78,8 @@ pub struct Location {
 impl Display for CompileMessage {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         let level = match self.level {
-            Level::Error => "Error",
-            Level::Warning => "Warning",
+            Level::Error => "error",
+            Level::Warning => "warning",
         };
         write!(f, "{}: {}", level, self.message)
     }
@@ -40,7 +90,7 @@ impl Error for CompileMessage {}
 impl CompileMessage {
     pub fn rich_format(&self, world: &World) -> String {
         format!(
-            "{}\n{}",
+            "{}\n  {}",
             self.to_string(),
             self.location.rich_format(&world)
         )

src/labels/parse.rs

@@ -3,11 +3,7 @@ use std::ops::Range;
 use compact_str::CompactString;
 use grammar::Tag;
 
-use crate::{
-    error::{CompileMessage, Level, Location},
-    peg::ParseState,
-    world::Stat,
-};
+use crate::{error::Context, peg::ParseState, world::Stat};
 
 pub type ParsedStat = Vec<Chunk>;
 
@@ -28,7 +24,7 @@ pub struct LabelName {
     pub local: Option<CompactString>,
 }
 
-pub fn parse_stat_labels(stat: &Stat) -> (ParsedStat, Vec<CompileMessage>) {
+pub fn parse_stat_labels(stat: &Stat, ctx: &Context) -> ParsedStat {
     let code = &stat.code;
     let mut parser = ParseState::new(code);
     assert!(
@@ -37,20 +33,11 @@ pub fn parse_stat_labels(stat: &Stat) -> (ParsedStat, Vec<CompileMessage>) {
         code
     );
 
-    let mut messages = vec![];
     for cap in parser.walk_captures() {
         match cap.kind() {
             Tag::WarnTrailing => {
-                messages.push(CompileMessage {
-                    level: Level::Warning,
-                    message: "Trailing characters at end of line".into(),
-                    location: Location {
-                        file_path: None,
-                        board: None,
-                        stat: None,
-                        span: Some(cap.span()),
-                    },
-                });
+                ctx.with_span(cap.span())
+                    .warning("trailing characters at end of line");
             }
             _ => {}
         }
@@ -106,7 +93,7 @@ pub fn parse_stat_labels(stat: &Stat) -> (ParsedStat, Vec<CompileMessage>) {
     if last_index < code.len() {
         result.push(Chunk::Verbatim(code[last_index..code.len()].into()));
     }
-    (result, messages)
+    result
 }
 
 mod grammar {

src/labels/process.rs

@@ -1,31 +1,20 @@
 use compact_str::CompactString;
 use rustc_hash::FxHashMap;
 
-use crate::{
-    error::{CompileMessage, CompileResult},
-    world::Board,
-};
+use crate::{error::Context, world::Board};
 
 use super::{
     parse::{Chunk, ParsedStat, parse_stat_labels},
     sanitize::Registry,
 };
 
-pub fn process_labels(board: &mut Board) -> CompileResult {
+pub fn process_labels(board: &mut Board, ctx: &Context) {
     // Parse stats into chunks
-    let mut messages: Vec<CompileMessage> = vec![];
     let mut stats: Vec<ParsedStat> = board
         .stats
         .iter()
         .enumerate()
-        .map(|(index, stat)| {
-            let (parsed_stat, mut new_messages) = parse_stat_labels(&stat);
-            new_messages
-                .iter_mut()
-                .for_each(|m| m.location.stat = Some(index));
-            messages.extend(new_messages);
-            parsed_stat
-        })
+        .map(|(index, stat)| parse_stat_labels(&stat, &ctx.with_stat(index)))
         .collect();
     let mut registry = Registry::new();
 
@@ -51,8 +40,6 @@ pub fn process_labels(board: &mut Board) -> CompileResult {
             .collect();
         old_stat.code = new_code;
     }
-
-    Ok(messages)
 }
 
 /// Resolve ".local" labels to "name.local" form.
@@ -218,7 +205,10 @@ mod test {
 
     use insta::assert_snapshot;
 
-    use crate::world::{Board, Stat};
+    use crate::{
+        error::Context,
+        world::{Board, Stat},
+    };
 
     use super::process_labels;
 
@@ -258,28 +248,28 @@ mod test {
     #[test]
     fn test_label_sanitization() {
         let mut board = board_from_text("tests/labels/sanitize.txt");
-        let _ = process_labels(&mut board);
+        let _ = process_labels(&mut board, &Context::default());
         assert_snapshot!(board_to_text(board));
     }
 
     #[test]
     fn test_anonymous_labels() {
         let mut board = board_from_text("tests/labels/anonymous.txt");
-        let _ = process_labels(&mut board);
+        let _ = process_labels(&mut board, &Context::default());
         assert_snapshot!(board_to_text(board));
     }
 
     #[test]
     fn test_local_labels() {
         let mut board = board_from_text("tests/labels/local.txt");
-        let _ = process_labels(&mut board);
+        let _ = process_labels(&mut board, &Context::default());
         assert_snapshot!(board_to_text(board));
     }
 
     #[test]
     fn test_namespaces() {
         let mut board = board_from_text("tests/labels/namespaces.txt");
-        let _ = process_labels(&mut board);
+        let _ = process_labels(&mut board, &Context::default());
         assert_snapshot!(board_to_text(board));
     }
 }

src/main.rs

@@ -6,6 +6,7 @@ mod preprocess;
 mod world;
 
 use anyhow::anyhow;
+use error::Context as ErrContext;
 use labels::process::process_labels;
 use preprocess::eval::Context;
 use std::{env, error::Error, fs, path::PathBuf, process::exit};
@@ -37,17 +38,14 @@ fn main() -> Result<(), Box<dyn Error>> {
     }
 
     // Resolve labels to proper ZZT-OOP
-    let mut messages = vec![];
+    let ctx = ErrContext::default().with_file_path(&world_filename);
     for (i, mut board) in world.boards.iter_mut().enumerate() {
-        let mut result = process_labels(&mut board).unwrap();
-        for message in result.iter_mut() {
-            message.location.board = Some(i);
-            message.location.file_path = Some(world_filename.clone());
-        }
-        messages.extend(result);
+        let ctx = ctx.with_board(i);
+        process_labels(&mut board, &ctx);
     }
 
     // Print diagnostics
+    let messages = ctx.into_messages();
     for (i, message) in messages.iter().enumerate() {
         if i > 0 {
             println!();