Use val/var again instead of let/mut

CHANGELOG.md

@@ -41,7 +41,7 @@
 - [ ] Parse bindings and function declarations as top level constructs
 - [ ] Parse function declaration arguments (`Type id`)
 - [ ] Parse function return datatype (`fun f() -> Type`)
-- [ ] Return parsing to variables to var/val
+- [x] Return parsing to variables to var/val
 - [ ] Write tests
 
 

src/lexic/scanner/identifier.rs

@@ -4,8 +4,8 @@ use crate::lexic::{token::Token, utils, LexResult};
 /// Checks if a String is a keyword, and returns its TokenType
 fn str_is_keyword(s: &String) -> Option<TokenType> {
     match s.as_str() {
-        "let" => Some(TokenType::LET),
-        "mut" => Some(TokenType::MUT),
+        "val" => Some(TokenType::VAL),
+        "var" => Some(TokenType::VAR),
         "fun" => Some(TokenType::FUN),
         _ => None,
     }
@@ -141,23 +141,23 @@ mod tests {
     // Should scan keywords
     #[test]
     fn test_4() {
-        let input = str_to_vec("mut");
+        let input = str_to_vec("var");
         let start_pos = 0;
         if let LexResult::Some(token, next) = scan(*input.get(0).unwrap(), &input, start_pos) {
             assert_eq!(3, next);
-            assert_eq!(TokenType::MUT, token.token_type);
-            assert_eq!("mut", token.value);
+            assert_eq!(TokenType::VAR, token.token_type);
+            assert_eq!("var", token.value);
             assert_eq!(0, token.position);
         } else {
             panic!()
         }
 
-        let input = str_to_vec("let");
+        let input = str_to_vec("val");
         let start_pos = 0;
         if let LexResult::Some(token, next) = scan(*input.get(0).unwrap(), &input, start_pos) {
             assert_eq!(3, next);
-            assert_eq!(TokenType::LET, token.token_type);
-            assert_eq!("let", token.value);
+            assert_eq!(TokenType::VAL, token.token_type);
+            assert_eq!("val", token.value);
             assert_eq!(0, token.position);
         } else {
             panic!()

src/lexic/token.rs

@@ -16,8 +16,8 @@ pub enum TokenType {
     Comma,
     INDENT,
     DEDENT,
-    LET,
-    MUT,
+    VAL,
+    VAR,
     EOF,
     FUN,
 }

src/semantic/impls.rs

@@ -32,7 +32,7 @@ impl SemanticCheck for TopLevelDeclaration<'_> {
                         error_start: binding.identifier.position,
                         error_end: binding.identifier.get_end_position(),
                         reason: format!(
-                            "Duplicated function: A function with name {} was already defined",
+                            "Duplicated: A symbol with name {} was already defined",
                             binding_name
                         ),
                     };
@@ -72,7 +72,7 @@ impl SemanticCheck for TopLevelDeclaration<'_> {
                         error_start: function.identifier.position,
                         error_end: function.identifier.get_end_position(),
                         reason: format!(
-                            "Duplicated function: A function with name {} was already defined",
+                            "Duplicated: A symbol with name {} was already defined",
                             function_name
                         ),
                     };

src/syntax/binding.rs

@@ -14,16 +14,15 @@ pub fn try_parse<'a>(tokens: &'a Vec<Token>, pos: usize) -> ParsingResult<Bindin
      * let keyword
      */
     let (is_mutable, binding_token, next_pos) = {
-        let let_token = parse_token_type(tokens, current_pos, TokenType::LET);
-        match let_token {
-            Ok((let_token, next_let)) => {
-                let mut_token = parse_token_type(tokens, next_let, TokenType::MUT);
-                match mut_token {
-                    Ok((_mut_token, next_mut)) => (true, let_token, next_mut),
-                    _ => (false, let_token, next_let),
+        match parse_token_type(tokens, current_pos, TokenType::VAL) {
+            Ok((val_token, next_pos)) => (false, val_token, next_pos),
+            _ => {
+                // If VAL is not found, search for VAR
+                match parse_token_type(tokens, current_pos, TokenType::VAR) {
+                    Ok((var_token, next_pos)) => (true, var_token, next_pos),
+                    _ => return Err(ParsingError::Unmatched),
                 }
             }
-            _ => return Err(ParsingError::Unmatched),
         }
     };
     current_pos = next_pos;
@@ -112,7 +111,7 @@ mod tests {
 
     #[test]
     fn should_parse_val_binding() {
-        let tokens = get_tokens(&String::from("let identifier = 20")).unwrap();
+        let tokens = get_tokens(&String::from("val identifier = 20")).unwrap();
         let Ok((binding, _)) = try_parse(&tokens, 0) else {
             panic!()
         };
@@ -122,11 +121,11 @@ mod tests {
 
     #[test]
     fn should_parse_val() {
-        let tokens = get_tokens(&String::from("let")).unwrap();
-        let (token, _) = parse_token_type(&tokens, 0, TokenType::LET).unwrap();
+        let tokens = get_tokens(&String::from("val")).unwrap();
+        let (token, _) = parse_token_type(&tokens, 0, TokenType::VAL).unwrap();
 
-        assert_eq!(TokenType::LET, token.token_type);
-        assert_eq!("let", token.value);
+        assert_eq!(TokenType::VAL, token.token_type);
+        assert_eq!("val", token.value);
     }
 
     #[test]
@@ -168,8 +167,8 @@ mod tests {
 
     #[test]
     fn should_return_correct_error() {
-        let tokens = get_tokens(&String::from("let")).unwrap();
-        assert_eq!(TokenType::LET, tokens[0].token_type);
+        let tokens = get_tokens(&String::from("val")).unwrap();
+        assert_eq!(TokenType::VAL, tokens[0].token_type);
         assert_eq!(0, tokens[0].position);
         let binding = try_parse(&tokens, 0);
 
@@ -184,8 +183,8 @@ mod tests {
 
     #[test]
     fn should_return_error_when_identifier_is_wrong() {
-        let tokens = get_tokens(&String::from("let 322")).unwrap();
-        assert_eq!(TokenType::LET, tokens[0].token_type);
+        let tokens = get_tokens(&String::from("val 322")).unwrap();
+        assert_eq!(TokenType::VAL, tokens[0].token_type);
         assert_eq!(0, tokens[0].position);
         let binding = try_parse(&tokens, 0);
 
@@ -197,7 +196,7 @@ mod tests {
             _ => panic!("Error expected"),
         }
 
-        let tokens = get_tokens(&String::from("let \"hello\"")).unwrap();
+        let tokens = get_tokens(&String::from("val \"hello\"")).unwrap();
         let binding = try_parse(&tokens, 0);
 
         match binding {
@@ -211,7 +210,7 @@ mod tests {
 
     #[test]
     fn should_return_error_when_equal_op_is_wrong() {
-        let tokens = get_tokens(&String::from("let id \"error\"")).unwrap();
+        let tokens = get_tokens(&String::from("val id \"error\"")).unwrap();
         let binding = try_parse(&tokens, 0);
 
         match binding {

src/syntax/grammar.md

@@ -16,6 +16,7 @@ simple function calls, and then implement other features top down
 ```ebnf
 top level statement = expression
                     | function declaration
+                    | binding
 ```
 
 

src/syntax/mod.rs

@@ -81,6 +81,22 @@ fn next_construct<'a>(
         _ => {}
     }
 
+    // Try to parse a binding
+    match binding::try_parse(tokens, current_pos) {
+        Ok((binding, next_pos)) => return Ok((TopLevelDeclaration::Binding(binding), next_pos)),
+        Err(ParsingError::Err(err)) => return Err(ParsingError::Err(err)),
+        _ => {}
+    }
+
+    // Try to parse an expression
+    match expression::try_parse(tokens, current_pos) {
+        Ok((expression, next_pos)) => {
+            return Ok((TopLevelDeclaration::Expression(expression), next_pos))
+        }
+        Err(ParsingError::Err(err)) => return Err(ParsingError::Err(err)),
+        _ => {}
+    }
+
     // No top level construct was found, return unmatched
     Err(ParsingError::Unmatched)
 }

src/syntax/statement.rs

@@ -49,7 +49,7 @@ mod tests {
 
     #[test]
     fn should_parse_binding() {
-        let input = String::from("let identifier = 20");
+        let input = String::from("val identifier = 20");
         let tokens = crate::lexic::get_tokens(&input).unwrap();
         let statement = try_parse(&tokens, 0);