wip:

Add type system and refator for having only epression

src/frontend/lexer.rs

@@ -16,7 +16,7 @@ pub struct Lexer {
 fn get_keyword_token(word: &str) -> Option<TokenType> {
     match word {
         "and" => Some(TokenType::And),
-        "class" => Some(TokenType::Class),
+        "struct" => Some(TokenType::Struct),
         "do" => Some(TokenType::StartBlock),
         "end" => Some(TokenType::EndBlock),
         "false" => Some(TokenType::False),
@@ -514,4 +514,32 @@ mod tests {
         assert_eq!(tokens[1].source_slice.start_position.line, 1);
         assert_eq!(tokens[1].source_slice.start_position.column, 0);
     }
+
+    #[test]
+    fn handle_struct() {
+        let tokens = lex("Cosa :: struct {field1: Number, field2: String}");
+        let tokens_tyepe: Vec<TokenType> = tokens.iter().map(|x| x.token_type.clone()).collect();
+        let tokent_for_check = vec![
+            TokenType::Identifier,
+            TokenType::Colon,
+            TokenType::Colon,
+            TokenType::Struct,
+            TokenType::LeftBrace,
+            TokenType::Identifier,
+            TokenType::Colon,
+            TokenType::Identifier,
+            TokenType::Comma,
+            TokenType::Identifier,
+            TokenType::Colon,
+            TokenType::Identifier,
+            TokenType::RightBrace,
+            TokenType::Eof,
+        ];
+        assert_eq!(tokens_tyepe, tokent_for_check);
+        assert_eq!(tokens[0].lexeme, "Cosa");
+        assert_eq!(tokens[5].lexeme, "field1");
+        assert_eq!(tokens[7].lexeme, "Number");
+        assert_eq!(tokens[9].lexeme, "field2");
+        assert_eq!(tokens[11].lexeme, "String");
+    }
 }