Make environment generic and adapt closures

Added unit test

src/frontend/parser.rs

@@ -205,6 +205,10 @@ impl Parser {
 
         let mut _type_annotation = BaseValue::Nil;
         self.consume(TokenType::Colon, "Expect column")?;
+        if self.peek().token_type == TokenType::Identifier {
+            // TODO manage type annotation
+            self.consume(TokenType::Identifier, "Expect type name.")?;
+        }
 
         match self.peek().token_type {
             TokenType::Equal | TokenType::Identifier => {
@@ -374,11 +378,7 @@ impl Parser {
 
         while self.peek().token_type != TokenType::EndBlock && !self.is_at_end() {
             let stmt = self.statement(label.clone())?;
-            let should_break = matches!(stmt.node, Stmt::Expression { .. });
             statements.push(stmt);
-            if should_break {
-                break;
-            }
         }
         let end_token = self.consume(TokenType::EndBlock, "Expect 'end' after block.")?;
         let end_slice = end_token.source_slice.clone();
@@ -864,3 +864,154 @@ impl Parser {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::common::base_value::Number;
+    use crate::frontend::lexer::Lexer;
+
+    /// Lex and parse `src`, returning the parser's result.
+    fn parse_source(src: &str) -> LoxResult<Vec<AstNode<Stmt>>> {
+        let tokens = Lexer::new(src.to_string(), 0)
+            .scans_tokens()
+            .expect("source should lex without errors");
+        Parser::new(tokens).parse()
+    }
+
+    /// Parse `src`, panicking if parsing fails.
+    fn parse_ok(src: &str) -> Vec<AstNode<Stmt>> {
+        parse_source(src).expect("expected source to parse")
+    }
+
+    /// Extract the inner expression of an expression statement.
+    fn expression_of(stmt: &AstNode<Stmt>) -> &AstNode<Expr> {
+        match &stmt.node {
+            Stmt::Expression { expression, .. } => expression,
+            other => panic!("expected expression statement, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn parses_number_literal_expression() {
+        let stmts = parse_ok("42;");
+        assert_eq!(stmts.len(), 1);
+        match &expression_of(&stmts[0]).node {
+            Expr::Literal { value } => {
+                assert_eq!(*value, BaseValue::Number(Number::I32(42)));
+            }
+            other => panic!("expected literal, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn respects_multiplication_precedence_over_addition() {
+        // 1 + 2 * 3 should parse as 1 + (2 * 3)
+        let stmts = parse_ok("1 + 2 * 3;");
+        match &expression_of(&stmts[0]).node {
+            Expr::Binary {
+                operator, right, ..
+            } => {
+                assert_eq!(*operator, TokenType::Plus);
+                match &right.node {
+                    Expr::Binary { operator, .. } => {
+                        assert_eq!(*operator, TokenType::Star)
+                    }
+                    other => panic!("expected nested binary, got {:?}", other),
+                }
+            }
+            other => panic!("expected binary expression, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn parses_unary_negation() {
+        let stmts = parse_ok("-5;");
+        match &expression_of(&stmts[0]).node {
+            Expr::Unary { operator, .. } => assert_eq!(*operator, TokenType::Minus),
+            other => panic!("expected unary expression, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn parses_grouping_to_change_precedence() {
+        // (1 + 2) * 3 should have a grouping on the left of the multiply.
+        let stmts = parse_ok("(1 + 2) * 3;");
+        match &expression_of(&stmts[0]).node {
+            Expr::Binary { operator, left, .. } => {
+                assert_eq!(*operator, TokenType::Star);
+                assert!(matches!(left.node, Expr::Grouping { .. }));
+            }
+            other => panic!("expected binary expression, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn parses_comparison_expression() {
+        let stmts = parse_ok("1 < 2;");
+        match &expression_of(&stmts[0]).node {
+            Expr::Binary { operator, .. } => assert_eq!(*operator, TokenType::Less),
+            other => panic!("expected binary expression, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn parses_print_statement() {
+        let stmts = parse_ok("print 1;");
+        assert!(matches!(stmts[0].node, Stmt::Print { .. }));
+    }
+
+    #[test]
+    fn parses_var_declaration_with_initializer() {
+        let stmts = parse_ok("var x: Int = 5;");
+        match &stmts[0].node {
+            Stmt::VarDeclaration {
+                name, initializer, ..
+            } => {
+                assert_eq!(name, "x");
+                assert!(initializer.is_some());
+            }
+            other => panic!("expected var declaration, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn parses_assignment_statement() {
+        let stmts = parse_ok("x = 5;");
+        match &stmts[0].node {
+            Stmt::VarAssigment { name, .. } => assert_eq!(name, "x"),
+            other => panic!("expected assignment statement, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn parses_block_statement() {
+        let stmts = parse_ok("do print 1; print 2; end");
+        match &stmts[0].node {
+            Stmt::Block { statements, .. } => assert_eq!(statements.len(), 2),
+            other => panic!("expected block statement, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn parses_if_statement() {
+        let stmts = parse_ok("if true then print 1;");
+        assert!(matches!(stmts[0].node, Stmt::If { .. }));
+    }
+
+    #[test]
+    fn parses_while_statement() {
+        let stmts = parse_ok("while true do print 1; end");
+        assert!(matches!(stmts[0].node, Stmt::While { .. }));
+    }
+
+    #[test]
+    fn errors_on_missing_semicolon_after_print() {
+        assert!(parse_source("print 1").is_err());
+    }
+
+    #[test]
+    fn errors_on_unclosed_grouping() {
+        assert!(parse_source("(1 + 2;").is_err());
+    }
+}