Merge branch 'main' into beta-0.4

musique/errors.cc

@@ -201,7 +201,12 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 			print_error_line(loc);
 
 			os << "Variables can only be references in scope (block) where they been created\n";
-			os << "or from parent blocks to variable block\n";
+			os << "or from parent blocks to variable block\n\n";
+
+			pretty::begin_comment(os);
+			os << "Maybe you want to defined it. To do this you must use ':=' operator.\n";
+			os << "   name := value\n";
+			pretty::end(os);
 		},
 		[&](errors::Unrecognized_Character const& err) {
 			os << "I encountered character in the source code that was not supposed to be here.\n";
@@ -268,7 +273,7 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 
 		[&](errors::Unsupported_Types_For const& err) {
 			switch (err.type) {
-			case errors::Unsupported_Types_For::Function:
+			break; case errors::Unsupported_Types_For::Function:
 				{
 					os << "I tried to call function '" << err.name << "' but you gave me wrong types for it!\n";
 
@@ -281,9 +286,26 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 						os << "  " << possibility << '\n';
 					}
 				}
-				break;
+			break; case errors::Unsupported_Types_For::Operator:
-			case errors::Unsupported_Types_For::Operator:
 				{
+					if (err.name == "=") {
+						os << "Operator '=' expects name on it's left side.\n";
+						os << "\n";
+
+						print_error_line(loc);
+
+						pretty::begin_comment(os);
+						os << "If you want to test if two values are equal use '==' operator:\n";
+					  // TODO Maybe we can use code serialization mechanism to print here actual equation
+					  // but transformed to account for use of == operator. If produced string is too big
+					  // then we can skip and show this silly example
+						os << "  3 == 4\n";
+						os << "If you want to change element of an array use update function:\n";
+						os << "  instead of a[i] = x you may write a = update a i x\n";
+						pretty::end(os);
+						return;
+					}
+
 					os << "I tried and failed to evaluate operator '" << err.name << "' due to values with wrong types provided\n";
 					os << "Make sure that both values matches one of supported signatures listed below!\n";
 					os << '\n';
@@ -297,7 +319,6 @@ std::ostream& operator<<(std::ostream& os, Error const& err)
 						os << "  " << possibility << '\n';
 					}
 				}
-				break;
 			}
 		},
 

musique/errors.hh

@@ -45,19 +45,19 @@ namespace errors
 	/// When user forgot semicolon or brackets
 	struct Expected_Expression_Separator_Before
 	{
-		std::string_view what;
+		std::string what;
 	};
 
 	/// When some keywords are not allowed in given context
 	struct Unexpected_Keyword
 	{
-		std::string_view keyword;
+		std::string keyword;
 	};
 
 	/// When user tried to use operator that was not defined
 	struct Undefined_Operator
 	{
-		std::string_view op;
+		std::string op;
 	};
 
 	/// When user tries to use operator with wrong arity of arguments
@@ -67,7 +67,7 @@ namespace errors
 		enum Type { Operator, Function } type;
 
 		/// Name of operation
-		std::string_view name;
+		std::string name;
 
 		/// Arity that was expected by given operation
 		size_t expected_arity;
@@ -79,15 +79,15 @@ namespace errors
 	/// When user tried to call something that can't be called
 	struct Not_Callable
 	{
-		std::string_view type;
+		std::string type;
 	};
 
 	/// When user provides literal where identifier should be
 	struct Literal_As_Identifier
 	{
-		std::string_view type_name;
+		std::string type_name;
-		std::string_view source;
+		std::string source;
-		std::string_view context;
+		std::string context;
 	};
 
 	/// When user provides wrong type for given operation
@@ -108,6 +108,10 @@ namespace errors
 	{
 		/// Name of variable
 		std::string name;
+
+		// TODO std::vector<std::string> similar_names;
+		// Pull all names reachable from given point and similar onces
+		// put in this array
 	};
 
 	/// When user tries to invoke some MIDI action but haven't established MIDI connection
@@ -155,13 +159,13 @@ namespace errors
 		struct Unexpected_Token
 		{
 			/// Type of the token
-			std::string_view type;
+			std::string type;
 
 			/// Source of the token
-			std::string_view source;
+			std::string source;
 
 			/// Where this token was encountered that was unexpected?
-			std::string_view when;
+			std::string when;
 		};
 	}
 

musique/interpreter/interpreter.cc

@@ -90,11 +90,27 @@ Result<Value> Interpreter::eval(Ast &&ast)
 			if (ast.token.source == "=") {
 				auto lhs = std::move(ast.arguments.front());
 				auto rhs = std::move(ast.arguments.back());
-				ensure(lhs.type == Ast::Type::Literal && lhs.token.type == Token::Type::Symbol,
+
-					"Currently LHS of assigment must be an identifier"); // TODO(assert)
+				if (lhs.type != Ast::Type::Literal || lhs.token.type != Token::Type::Symbol) {
+					return Error {
+						.details = errors::Unsupported_Types_For {
+							.type = errors::Unsupported_Types_For::Operator,
+							.name = "=",
+							.possibilities = {},
+						},
+						.location = ast.token.location,
+					};
+				}
 
 				Value *v = env->find(std::string(lhs.token.source));
-				ensure(v, "Cannot resolve variable: "s + std::string(lhs.token.source)); // TODO(assert)
+				if (v == nullptr) {
+					return Error {
+						.details = errors::Missing_Variable {
+							.name = std::string(lhs.token.source)
+						},
+						.location = lhs.location,
+					};
+				}
 				return *v = Try(eval(std::move(rhs)).with_location(ast.token.location));
 			}
 
@@ -118,7 +134,7 @@ Result<Value> Interpreter::eval(Ast &&ast)
 					auto op = operators.find(std::string(ast.token.source.substr(0, ast.token.source.size()-1)));
 					if (op == operators.end()) {
 						return Error {
-							.details = errors::Undefined_Operator { .op = ast.token.source },
+							.details = errors::Undefined_Operator { .op = std::string(ast.token.source) },
 							.location = ast.token.location
 						};
 					}
@@ -137,7 +153,7 @@ Result<Value> Interpreter::eval(Ast &&ast)
 				}
 
 				return Error {
-					.details = errors::Undefined_Operator { .op = ast.token.source },
+					.details = errors::Undefined_Operator { .op = std::string(ast.token.source) },
 					.location = ast.token.location
 				};
 			}

musique/parser/parser.cc

@@ -248,7 +248,7 @@ Result<Ast> Parser::parse_atomic_expression()
 		// So we need to explicitly allow only keywords that are also literals
 		if (std::find(Literal_Keywords.begin(), Literal_Keywords.end(), peek()->source) == Literal_Keywords.end()) {
 			return Error {
-				.details = errors::Unexpected_Keyword { .keyword = peek()->source },
+				.details = errors::Unexpected_Keyword { .keyword = std::string(peek()->source) },
 				.location = peek()->location
 			};
 		}
@@ -313,8 +313,8 @@ Result<Ast> Parser::parse_atomic_expression()
 					if (success && invalid_token) {
 						return Error {
 							.details = errors::Literal_As_Identifier {
-								.type_name = type_name(invalid_token->type),
+								.type_name = std::string(type_name(invalid_token->type)),
-								.source = invalid_token->source,
+								.source = std::string(invalid_token->source),
 								.context = "block parameter list"
 							},
 							.location = invalid_token->location
@@ -329,7 +329,7 @@ Result<Ast> Parser::parse_atomic_expression()
 		return Error {
 			.details = errors::Wrong_Arity_Of {
 				.type = errors::Wrong_Arity_Of::Operator,
-				.name = peek()->source,
+				.name = std::string(peek()->source),
 				.expected_arity = 2, // TODO This should be resolved based on operator
 				.actual_arity = 0,
 			},
@@ -340,8 +340,8 @@ Result<Ast> Parser::parse_atomic_expression()
 	default:
 		return Error {
 			.details = errors::internal::Unexpected_Token {
-				.type = type_name(peek()->type),
+				.type = std::string(type_name(peek()->type)),
-				.source = peek()->source,
+				.source = std::string(peek()->source),
 				.when = "atomic expression parsing"
 			},
 			.location = peek()->location
@@ -355,8 +355,8 @@ Result<Ast> Parser::parse_identifier_with_trailing_separators()
 		// TODO Specific error message
 		return Error {
 			.details = errors::internal::Unexpected_Token {
-				.type = type_name(peek()->type),
+				.type = std::string(type_name(peek()->type)),
-				.source = peek()->source,
+				.source = std::string(peek()->source),
 				.when = "identifier parsing"
 			},
 			.location = peek()->location
@@ -373,8 +373,8 @@ Result<Ast> Parser::parse_identifier()
 		// TODO Specific error message
 		return Error {
 			.details = errors::internal::Unexpected_Token {
-				.type = type_name(peek()->type),
+				.type = std::string(type_name(peek()->type)),
-				.source = peek()->source,
+				.source = std::string(peek()->source),
 				.when = "identifier parsing"
 			},
 			.location = peek()->location

musique/value/value.cc

@@ -113,7 +113,7 @@ Result<Value> Value::operator()(Interpreter &i, std::vector<Value> args) const
 		return (*func)(i, std::move(args));
 	}
 
-	return errors::Not_Callable { .type = type_name(*this) };
+	return errors::Not_Callable { .type = std::string(type_name(*this)) };
 }