Add better error reporting for repl.

dm/src/common.rs

@@ -0,0 +1,43 @@
+use codespan_reporting::diagnostic::Label;
+use dmc_lib::diagnostic::Diagnostic;
+
+pub fn to_csr_diagnostic(
+    file_id: usize,
+    diagnostic: &Diagnostic,
+) -> codespan_reporting::diagnostic::Diagnostic<usize> {
+    let mut primary_label = Label::primary(file_id, diagnostic.start()..diagnostic.end());
+    if let Some(primary_label_message) = diagnostic.primary_label_message() {
+        primary_label = primary_label.with_message(primary_label_message);
+    }
+
+    let secondary_labels: Vec<Label<usize>> = diagnostic
+        .secondary_labels()
+        .iter()
+        .map(|secondary_label| {
+            let mut label =
+                Label::secondary(file_id, secondary_label.start()..secondary_label.end());
+            if let Some(message) = secondary_label.message() {
+                label = label.with_message(message);
+            }
+            label
+        })
+        .collect();
+
+    let mut csr_diagnostic = codespan_reporting::diagnostic::Diagnostic::error()
+        .with_message(diagnostic.message())
+        .with_label(primary_label)
+        .with_labels(secondary_labels);
+
+    if let Some(error_code) = diagnostic.error_code() {
+        csr_diagnostic = csr_diagnostic.with_code(format!("E{:04}", error_code));
+    }
+
+    if let Some((reporter_file, reporter_line)) = diagnostic.reporter() {
+        csr_diagnostic = csr_diagnostic.with_note(format!(
+            "Reported by (Rust) source: {}, line {}",
+            reporter_file, reporter_line
+        ));
+    }
+
+    csr_diagnostic
+}

dm/src/main.rs

@@ -1,9 +1,11 @@
+mod common;
 mod repl;
 mod run;
 
 use crate::repl::repl;
 use crate::run::compile_and_run_script;
 use clap::{Parser, Subcommand};
+use codespan_reporting::term::termcolor::{ColorChoice, StandardStream};
 use std::io;
 use std::path::PathBuf;
 
@@ -47,7 +49,7 @@ fn main() {
             repl(
                 &mut io::stdin().lock(),
                 &mut io::stdout().lock(),
-                &mut io::stderr().lock(),
+                &mut StandardStream::stderr(ColorChoice::Always),
                 register_count,
             );
         }

dm/src/repl.rs

@@ -1,3 +1,6 @@
+use crate::common::to_csr_diagnostic;
+use codespan_reporting::files::SimpleFiles;
+use codespan_reporting::term::{Config, WriteStyle, emit_to_write_style};
 use dmc_lib::SyntheticFunctionSession;
 use dmc_lib::constants_table::ConstantsTable;
 use dmc_lib::diagnostic::Diagnostics;
@@ -11,9 +14,13 @@ use std::io::{BufRead, Write};
 pub fn repl(
     read: &mut impl BufRead,
     out: &mut impl Write,
-    err: &mut impl Write,
+    err: &mut impl WriteStyle,
     register_count: usize,
 ) {
+    let diagnostics_config = Config::default();
+    let mut files: SimpleFiles<&str, String> = SimpleFiles::new();
+    let mut current_file_id;
+
     let mut buffer = String::new();
 
     let mut session = SyntheticFunctionSession::new("__repl");
@@ -48,8 +55,10 @@ pub fn repl(
                     .insert(function.name_owned(), function);
             }
             Err(diagnostics) => {
+                current_file_id = files.add("input", String::from(input));
                 for diagnostic in diagnostics {
-                    writeln!(err, "{}", diagnostic.message()).unwrap();
+                    let csr_diagnostic = to_csr_diagnostic(current_file_id, &diagnostic);
+                    emit_to_write_style(err, &diagnostics_config, &files, &csr_diagnostic).unwrap();
                 }
                 buffer.clear();
                 continue 'repl;

dm/src/run.rs

@@ -1,4 +1,4 @@
-use codespan_reporting::diagnostic::Label;
+use crate::common::to_csr_diagnostic;
 use codespan_reporting::files::SimpleFiles;
 use codespan_reporting::term;
 use codespan_reporting::term::termcolor::{ColorChoice, StandardStream};
@@ -88,43 +88,7 @@ fn report_and_exit(
     let writer = StandardStream::stderr(ColorChoice::Always);
     let config = term::Config::default();
     for diagnostic in diagnostics {
-        let mut primary_label =
+        let csr_diagnostic = to_csr_diagnostic(script_file_id, diagnostic);
-            Label::primary(script_file_id, diagnostic.start()..diagnostic.end());
-        if let Some(primary_label_message) = diagnostic.primary_label_message() {
-            primary_label = primary_label.with_message(primary_label_message);
-        }
-
-        let secondary_labels: Vec<Label<usize>> = diagnostic
-            .secondary_labels()
-            .iter()
-            .map(|secondary_label| {
-                let mut label = Label::secondary(
-                    script_file_id,
-                    secondary_label.start()..secondary_label.end(),
-                );
-                if let Some(message) = secondary_label.message() {
-                    label = label.with_message(message);
-                }
-                label
-            })
-            .collect();
-
-        let mut csr_diagnostic = codespan_reporting::diagnostic::Diagnostic::error()
-            .with_message(diagnostic.message())
-            .with_label(primary_label)
-            .with_labels(secondary_labels);
-
-        if let Some(error_code) = diagnostic.error_code() {
-            csr_diagnostic = csr_diagnostic.with_code(format!("E{:04}", error_code));
-        }
-
-        if let Some((reporter_file, reporter_line)) = diagnostic.reporter() {
-            csr_diagnostic = csr_diagnostic.with_note(format!(
-                "Reported by (Rust) source: {}, line {}",
-                reporter_file, reporter_line
-            ));
-        }
-
         term::emit_to_write_style(&mut writer.lock(), &config, files, &csr_diagnostic).unwrap();
     }
     if diagnostics.len() == 1 {