better parser errors

error_test/parser/bracket_errors.sui

@@ -1,47 +1,50 @@
 # Bracket and parenthesis mismatch errors
 
 # Missing closing parenthesis in function call
-fn test() -> int
+fn test() -> int do
     let f = lambda(x) x
     f(5
     42
+end
 
 # Missing closing bracket in array access
-fn test() -> int
+fn test() -> int do
     let arr = [1, 2, 3]
     arr[0
     42
+end
+
+struct Point
+   x: int,
+   y: int
+end
 
 # Missing closing brace in struct literal
-fn test() -> int
-    struct Point
-        x: int
-        y: int
-    end
+fn test() -> int do 
     let p = Point { x: 5, y: 10
     p.x
+end
 
 # Missing closing parenthesis in tuple
-fn test() -> int
+fn test() -> int do
     let t = (1, 2, 3
     42
+end
 
 # Missing closing angle bracket in generic
-fn test() -> int
+fn test() -> int do
     let v = Vec<int
     42
+end
 
 # Extra closing parenthesis
-fn test() -> int
+fn test() -> int do
     let x = (5))
     x
-
-# Mismatched brackets
-fn test() -> int
-    let x = [1, 2, 3}
-    x[0]
+end
 
 # Missing opening parenthesis in expression
-fn test() -> int
+fn test() -> int do
     let x = 5 + 3)
-    x
+    x
+end

error_test/parser/control_flow_errors.sui

@@ -17,19 +17,16 @@ fn test() -> int
 fn test() -> int
     for in [1, 2, 3]
         item
-    0
 
 # Missing 'in' keyword in for loop
 fn test() -> int
     for item [1, 2, 3]
         item
-    0
 
 # Missing iterable in for loop
 fn test() -> int
     for item in
         item
-    0
 
 # Invalid while syntax
 fn test() -> int
@@ -40,10 +37,8 @@ fn test() -> int
 fn test() -> int
     let f = lambda
         42
-    f()
 
 # Missing closing parenthesis in lambda
 fn test() -> int
     let f = lambda(x
         x
-    f(5)

error_test/parser/enum_errors.sui

@@ -1,29 +0,0 @@
-# Enum syntax errors
-
-# Missing enum name
-enum
-    Red
-    Green
-end
-
-# Missing variant name
-enum Color
-    Red
-    Green
-end
-
-# Invalid variant syntax (missing parentheses for tuple variant)
-enum Result
-    Ok int
-    Err string
-end
-
-# Missing comma between variants
-enum Color
-    Red Green
-end
-
-# Missing end keyword
-enum Color
-    Red
-    Green

error_test/parser/expression_errors.sui

@@ -1,43 +0,0 @@
-# Expression and statement errors
-
-# Missing variable name in let
-fn test() -> int
-    let = 5
-    42
-
-# Missing equals in assignment
-fn test() -> int
-    let x 5
-    x
-
-# Missing expression after operator
-fn test() -> int
-    5 +
-
-# Invalid array syntax (missing comma)
-fn test() -> int
-    let arr = [1 2 3]
-    arr[0]
-
-# Missing closing bracket in array
-fn test() -> int
-    let arr = [1, 2, 3
-    arr[0]
-
-# Invalid struct literal (missing field value)
-fn test() -> int
-    struct Point
-        x: int
-        y: int
-    end
-    let p = Point { x: 5, y }
-    p.x
-
-# Missing colon in struct literal
-fn test() -> int
-    struct Point
-        x: int
-        y: int
-    end
-    let p = Point { x 5, y: 10 }
-    p.x

error_test/parser/pattern_errors.sui

@@ -1,5 +1,14 @@
 # Pattern matching errors
+struct Point
+  x: int,
+  y: int,
+end
 
+enum Result
+  Ok(int)
+  Err(string)
+end
+ 
 # Invalid pattern in match
 fn test() -> int
     match 42
@@ -7,26 +16,20 @@ fn test() -> int
     end
 
 # Missing colon in struct pattern
-fn test() -> int
-    struct Point
-        x: int
-        y: int
-    end
-    let p = Point { x: 5, y: 10 }
+fn test() -> int do
+   let p = Point { x: 5, y: 10 }
     match p
         Point { x 5, y: 10 } => 1
     end
+end
 
 # Invalid enum pattern
-fn test() -> int
-    enum Result
-        Ok(int)
-        Err(string)
-    end
-    let r = Result::Ok(42)
+fn test() -> int do
+   let r = Result::Ok(42)
     match r
         Result::Ok value => value
     end
+end
 
 # Missing pattern in match arm
 fn test() -> int
@@ -38,4 +41,4 @@ fn test() -> int
 fn test() -> int
     match 42
         x 0
-    end
+    end

error_test/parser/struct_errors.sui

@@ -2,7 +2,7 @@
 
 # Missing struct name
 struct
-    x: int
+    x: int,
     y: int
 end
 
@@ -14,17 +14,17 @@ end
 
 # Missing colon in field
 struct Point
-    x int
+    x int,
     y: int
 end
 
 # Missing end keyword
 struct Point
-    x: int
-    y: int
+    x: int,
+    y: int,
 
 # Invalid field separator (semicolon instead of comma)
 struct Point
     x: int;
     y: int
-end
+end

src/main.rs

@@ -44,6 +44,57 @@ fn run_test_suite() {
     }
 }
 
+fn format_parse_error(source: &str, error: &suicmez::parser::ParseError) -> String {
+
+    // Find the line containing the error
+    let lines: Vec<&str> = source.lines().collect();
+    let mut current_pos = 0;
+
+    for (line_idx, line) in lines.iter().enumerate() {
+        let line_start = current_pos;
+        let line_end = current_pos + line.len();
+
+        // Check if the error span intersects with this line
+        if error.span.start < line_end && error.span.end > line_start {
+            let mut result = String::new();
+
+            // Print the error message
+            result.push_str(&format!("Parse error: {}\n", error.message));
+
+            // Print the line number and content
+            result.push_str(&format!("{} | {}\n", line_idx + 1, line));
+
+            // Calculate column positions within the line
+            let line_start_col = error.span.start.saturating_sub(line_start);
+            let line_end_col = (error.span.end - line_start).min(line.len());
+
+            // Print spaces and squiggly line for the span
+            result.push_str(&format!("{} | ", " ".repeat((line_idx + 1).to_string().len())));
+            for _ in 0..line_start_col {
+                result.push(' ');
+            }
+            for _ in line_start_col..line_end_col {
+                result.push('~');
+            }
+            result.push('\n');
+
+            // Print caret at the start position
+            result.push_str(&format!("{} | ", " ".repeat((line_idx + 1).to_string().len())));
+            for _ in 0..line_start_col {
+                result.push(' ');
+            }
+            result.push('^');
+
+            return result;
+        }
+
+        current_pos = line_end + 1; // +1 for the newline character
+    }
+
+    // Fallback if we can't find the line
+    format!("Parse error: {} (at byte {})", error.message, error.span.start)
+}
+
 fn run_file(filename: &str) -> Result<(), String> {
     // Read the source file
     let source = fs::read_to_string(filename)
@@ -69,7 +120,7 @@ fn run_file(filename: &str) -> Result<(), String> {
     let mut parser = Parser::new(filename.to_string(), tokens);
     let ast_nodes = parser
         .parse()
-        .map_err(|e| format!("Parse error: {}", e.message))?;
+        .map_err(|e| format_parse_error(&source, &e))?;
 
     println!("Parsed {} AST nodes successfully", ast_nodes.len());