Missing semicolon error!

src/errors.cc

@@ -115,7 +115,8 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 		[](errors::Unexpected_Empty_Source const&)              { return "Unexpected end of file"; },
 		[](errors::Unexpected_Keyword const&)                   { return "Unexpected keyword"; },
 		[](errors::Unrecognized_Character const&)               { return "Unrecognized character"; },
-		[](errors::internal::Unexpected_Token const&)       { return "Unexpected token"; }
+		[](errors::internal::Unexpected_Token const&)           { return "Unexpected token"; },
+		[](errors::Expected_Expression_Separator_Before const&) { return "Missing semicolon"; }
 	}, err.details);
 
 	error_heading(os, err.location, Error_Level::Error, short_description);
@@ -148,13 +149,22 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 			encourage_contact(os);
 		},
 
-		[&os](errors::Expected_Keyword const&)                 {},
+		[&os](errors::Expected_Expression_Separator_Before const& err) {
-		[&os](errors::Music_Literal_Used_As_Identifier const&) {},
+			os << "I failed to parse following code, due to missing semicolon before it!\n";
-		[&os](errors::Not_Callable const&)                     {},
+
-		[&os](errors::Undefined_Identifier const&)             {},
+			if (err.what == "var") {
-		[&os](errors::Undefined_Operator const&)               {},
+				os << "\nIf you want to create variable inside expression try wrapping them inside parentheses like this:\n";
-		[&os](errors::Unexpected_Keyword const&)               {},
+				os << "    10 + (var i = 20)\n";
-		[&os](errors::Unexpected_Empty_Source const&)          {}
+			}
+		},
+
+		[&os](errors::Expected_Keyword const&)                 { unimplemented(); },
+		[&os](errors::Music_Literal_Used_As_Identifier const&) { unimplemented(); },
+		[&os](errors::Not_Callable const&)                     { unimplemented(); },
+		[&os](errors::Undefined_Identifier const&)             { unimplemented(); },
+		[&os](errors::Undefined_Operator const&)               { unimplemented(); },
+		[&os](errors::Unexpected_Keyword const&)               { unimplemented(); },
+		[&os](errors::Unexpected_Empty_Source const&)          { unimplemented(); }
 	}, err.details);
 
 	return os;

src/musique.hh

@@ -69,6 +69,11 @@ namespace errors
 		std::string_view received_type = {};
 	};
 
+	struct Expected_Expression_Separator_Before
+	{
+		std::string_view what;
+	};
+
 	struct Unexpected_Keyword
 	{
 		std::string_view keyword;
@@ -109,6 +114,7 @@ namespace errors
 	}
 
 	using Details = std::variant<
+		Expected_Expression_Separator_Before,
 		Expected_Keyword,
 		Failed_Numeric_Parsing,
 		Music_Literal_Used_As_Identifier,

src/parser.cc

@@ -40,6 +40,12 @@ Result<Ast> Parser::parse(std::string_view source, std::string_view filename)
 	auto const result = parser.parse_sequence();
 
 	if (parser.token_id < parser.tokens.size()) {
+		if (parser.expect(Token::Type::Keyword, "var")) {
+			return Error {
+				.details = errors::Expected_Expression_Separator_Before { .what = "var" },
+				.location = parser.peek()->location
+			};
+		}
 		errors::all_tokens_were_not_parsed(std::span(parser.tokens).subspan(parser.token_id));
 	}
 
@@ -54,10 +60,10 @@ Result<Ast> Parser::parse_sequence()
 
 Result<Ast> Parser::parse_expression()
 {
-	auto var = parse_variable_declaration();
+	if (expect(Token::Type::Keyword, "var")) {
-	if (!var.has_value())
+		return parse_variable_declaration();
+	}
 	return parse_infix_expression();
-	return var;
 }
 
 Result<Ast> Parser::parse_variable_declaration()