lowering error report

Cargo.lock

@@ -184,6 +184,7 @@ dependencies = [
 name = "hir"
 version = "0.1.0"
 dependencies = [
+ "levenshtein",
  "parser",
 ]
 
@@ -203,6 +204,12 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
+[[package]]
+name = "levenshtein"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db13adb97ab515a3691f56e4dbab09283d0b86cb45abd991d8634a9d6f501760"
+
 [[package]]
 name = "lexer"
 version = "0.1.0"

crates/diagnostic/src/lib.rs

@@ -116,5 +116,36 @@ impl Diagnostics {
 
             report.finish().print(Source::from(&src)).unwrap();
         }); // End errors reporting
+
+        let lower_error = self.errors.iter().filter_map(|kind| match kind {
+            Kind::LoweringError(error) => Some(error.clone()),
+            _ => None,
+        });
+
+        lower_error.into_iter()
+        .for_each(|e| {
+            let span = &e.span;
+            let message = &e.message;
+
+            let report = Report::build(ReportKind::Error, (), span.start)
+                .with_message(
+                    format!("{}", message)
+                )
+                .with_label(
+                    Label::new(span.clone())
+                    .with_message(
+                        format!("{}", message)
+                    )
+                    .with_color(Color::Red)
+                );
+
+            if let Some(note) = &e.note {
+                report
+                .with_note(note)
+                .finish().print(Source::from(&src)).unwrap();
+            } else {
+                report.finish().print(Source::from(&src)).unwrap();
+            }
+        });
     }
 }

crates/hir/Cargo.toml

@@ -8,3 +8,4 @@ edition = "2021"
 
 [dependencies]
 parser = { path = "../parser" }
+levenshtein = "1.0.5" # Used for error reporting

crates/hir/src/lib.rs

@@ -29,7 +29,8 @@ pub struct IR {
 #[derive(Debug)]
 pub struct LoweringError {
     pub span: Range<usize>,
-    pub message: String
+    pub message: String,
+    pub note: Option<String>,
 }
 
 impl IR {
@@ -82,7 +83,7 @@ pub fn expr_to_ir(expr: &Expr) -> (Option<IRKind>, Option<LoweringError>) {
             let name = match &name.0 {
                 Expr::Identifier(s) => s.clone(),
                 // Should never happen because the parser should have caught this
-                _ => return (None, Some(LoweringError { span: name.1.clone(), message: "Expected identifier".to_string() }))
+                _ => return (None, Some(LoweringError { span: name.1.clone(), message: "Expected identifier".to_string(), note: None }))
             };
             let mut largs = Vec::new(); // `largs` stand for lowered args
             // Iterate over args
@@ -101,7 +102,7 @@ pub fn expr_to_ir(expr: &Expr) -> (Option<IRKind>, Option<LoweringError>) {
             if_err_return!(value.1);
 
             let value = value.0.unwrap();
-            let ir_kind = IRKind::Define { name: name.clone(), type_hint: type_hint.clone(), value: Box::new(value) };
+            let ir_kind = IRKind::Define { name: name.clone(), type_hint: gen_type_hint(type_hint), value: Box::new(value) };
             return (Some(ir_kind), None);
         },
 
@@ -110,10 +111,14 @@ pub fn expr_to_ir(expr: &Expr) -> (Option<IRKind>, Option<LoweringError>) {
                 Expr::Identifier(s) => {
                     if INTRINSICS.contains(&s.as_str()) { s.clone() }
                     else {
-                        return (None, Some(LoweringError { span: name.1.clone(), message: format!("Unknown intrinsic: {}", s) }));
+                        return (None, Some(LoweringError {
+                            span: name.1.clone(),
+                            message: format!("Unknown intrinsic: `{}`", s),
+                            note: Some(format!("Did you mean: {}?", closet_intrinsic(s.to_string())))
+                        }));
                     }
                 }
-                _ => return (None, Some(LoweringError { span: name.1.clone(), message: "Expected identifier".to_string() }))
+                _ => return (None, Some(LoweringError { span: name.1.clone(), message: "Expected identifier".to_string(), note: None }))
             };
             let mut largs = Vec::new();
             for arg in &args.0 {
@@ -194,3 +199,17 @@ fn gen_type_hint(type_hint: &str) -> String {
         _ => { dbg!(type_hint); todo!() }
     }
 }
+
+// Get the closet intrinsic name to the given name
+fn closet_intrinsic(got: String) -> String {
+    let mut closest = String::new();
+    let mut closest_dist = std::usize::MAX;
+    for intrinsic in INTRINSICS.iter() {
+        let dist = levenshtein::levenshtein(got.as_str(), intrinsic);
+        if dist < closest_dist {
+            closest = intrinsic.to_string();
+            closest_dist = dist;
+        }
+    }
+    closest
+}

crates/parser/src/lib.rs

@@ -43,9 +43,9 @@ fn expr_parser() -> impl Parser<Token, Vec<Spanned<Expr>>, Error = Simple<Token>
     }).labelled("identifier");
 
     let literal = filter_map(|span, token| match token {
-        Token::Int(i) => Ok((Expr::Int(i), span)),
+        Token::Int(i)     => Ok((Expr::Int(i), span)),
         Token::Boolean(b) => Ok((Expr::Boolean(b), span)),
-        Token::String(s) => Ok((Expr::String(s), span)),
+        Token::String(s)  => Ok((Expr::String(s), span)),
         _ => Err(Simple::expected_input_found(span, Vec::new(), Some(token))),
     }).labelled("literal");
 

example/err.hz

@@ -1,2 +1,3 @@
--- Can't use Int as identifier
-let 123 = 123;
+fun main: int = do
+    @writse(); -- Unknown intrinsic
+end;

example/readwrite.hz

@@ -0,0 +1,9 @@
+fun main: int = do
+    @write("Enter your name: ");
+    let name: string = "";
+    @read(name);
+
+    @write("Hello ");
+    @write(name);
+    @write("!");
+end;