Merge pull request 'Improve Syntax Error Messages and Fix Comments' (#29) from kym-script-comments into main

Reviewed-on: #29

debug/app.ona

@@ -1,4 +1,5 @@
 
+# Test comment.
 @log_info("game is loading")
 
 return {

source/coral/list.zig

@@ -118,5 +118,7 @@ pub fn stack_as_writer(self: *ByteStack) io.Writer {
 }
 
 fn write_stack(stack: *ByteStack, bytes: []const io.Byte) ?usize {
-	return stack.push_all(bytes) catch null;
+	stack.push_all(bytes) catch return null;
+
+	return bytes.len;
 }

source/coral/math.zig

@@ -30,7 +30,9 @@ pub fn max_int(comptime int: std.builtin.Type.Int) comptime_int {
 }
 
 pub fn min_int(comptime int: std.builtin.Type.Int) comptime_int {
-    if (int.signedness == .unsigned) return 0;
+	if (int.signedness == .unsigned) {
+		return 0;
+	}
 
 	const bit_count = int.bits;
 

source/ona/kym.zig

@@ -8,8 +8,6 @@ const coral = @import("coral");
 
 const file = @import("./file.zig");
 
-const tokens = @import("./kym/tokens.zig");
-
 pub const Any = union (enum) {
 	nil,
 	boolean: bool,
@@ -200,18 +198,14 @@ pub const RuntimeEnv = struct {
 		name: []const coral.io.Byte,
 		data: []const coral.io.Byte,
 	) RuntimeError!?*RuntimeRef {
-		var ast = Ast.make(self.allocator);
+		var ast = Ast.make(self.allocator, name);
 
 		defer ast.free();
 
-		{
+		ast.parse(data) catch |parse_error| switch (parse_error) {
-			var tokenizer = tokens.Tokenizer{.source = data};
+			error.BadSyntax => return self.raise(error.BadSyntax, ast.error_message()),
-
-			ast.parse(&tokenizer) catch |parse_error| switch (parse_error) {
-				error.BadSyntax => return self.raise(error.BadSyntax, ast.error_message),
 			error.OutOfMemory => return error.OutOfMemory,
 		};
-		}
 
 		var chunk = Chunk.make(self);
 

source/ona/kym/Ast.zig

@@ -2,10 +2,12 @@ const coral = @import("coral");
 
 const tokens = @import("./tokens.zig");
 
+name: []const coral.io.Byte,
 allocator: coral.io.Allocator,
 arena: coral.arena.Stacking,
 statements: Statement.List,
-error_message: []const coral.io.Byte,
+error_buffer: coral.list.ByteStack,
+tokenizer: tokens.Tokenizer,
 
 pub const Expression = union (enum) {
 	nil_literal,
@@ -67,7 +69,7 @@ pub const Expression = union (enum) {
 	pub const List = coral.list.Stack(Expression);
 };
 
-const ExpressionParser = fn (self: *Self, tokenizer: *tokens.Tokenizer) ParseError!Expression;
+const ExpressionParser = fn (self: *Self) ParseError!Expression;
 
 pub const ParseError = error {
 	OutOfMemory,
@@ -103,25 +105,25 @@ fn binary_operation_parser(
 	comptime operators: []const Expression.BinaryOperator) ExpressionParser {
 
 	const BinaryOperationParser = struct {
-		fn parse(self: *Self, tokenizer: *tokens.Tokenizer) ParseError!Expression {
+		fn parse(self: *Self) ParseError!Expression {
 			const allocator = self.arena.as_allocator();
-			var expression = try parse_next(self, tokenizer);
+			var expression = try parse_next(self);
 
 			inline for (operators) |operator| {
 				const token = comptime operator.token();
 
-				if (tokenizer.is_token(coral.io.tag_of(token))) {
+				if (self.tokenizer.is_token(coral.io.tag_of(token))) {
-					tokenizer.step();
+					self.tokenizer.step();
 
-					if (tokenizer.token == null) {
+					if (self.tokenizer.token == null) {
-						return self.raise("expected other half of expression after `" ++ comptime token.text() ++ "`");
+						return self.report("expected other half of expression after `" ++ comptime token.text() ++ "`");
 					}
 
 					expression = .{
 						.binary_operation = .{
 							.operator = operator,
 							.lhs_expression = try coral.io.allocate_one(allocator, expression),
-							.rhs_expression = try coral.io.allocate_one(allocator, try parse_next(self, tokenizer)),
+							.rhs_expression = try coral.io.allocate_one(allocator, try parse_next(self)),
 						},
 					};
 				}
@@ -134,22 +136,33 @@ fn binary_operation_parser(
 	return BinaryOperationParser.parse;
 }
 
+pub fn error_message(self: Self) []const coral.io.Byte {
+	return self.error_buffer.values;
+}
+
 pub fn free(self: *Self) void {
 	self.arena.free();
 	self.statements.free();
+	self.error_buffer.free();
 }
 
-pub fn make(allocator: coral.io.Allocator) Self {
+pub fn make(allocator: coral.io.Allocator, ast_name: []const coral.io.Byte) Self {
 	return Self{
 		.arena = coral.arena.Stacking.make(allocator, 4096),
-		.allocator = allocator,
+		.error_buffer = coral.list.ByteStack.make(allocator),
 		.statements = Statement.List.make(allocator),
-		.error_message = "",
+		.tokenizer = .{.source = ""},
+		.allocator = allocator,
+		.name = ast_name,
 	};
 }
 
-fn raise(self: *Self, message: []const u8) ParseError {
+fn report(self: *Self, message: []const coral.io.Byte) ParseError {
-	self.error_message = message;
+	coral.utf8.print_formatted(coral.list.stack_as_writer(&self.error_buffer), "{name}@{line}: {message}", .{
+		.name = self.name,
+		.line = self.tokenizer.lines_stepped,
+		.message = message,
+	}) catch return error.OutOfMemory;
 
 	return error.BadSyntax;
 }
@@ -158,32 +171,30 @@ pub fn list_statements(self: Self) []const Statement {
 	return self.statements.values;
 }
 
-pub fn parse(self: *Self, tokenizer: *tokens.Tokenizer) ParseError!void {
+pub fn parse(self: *Self, data: []const coral.io.Byte) ParseError!void {
-	self.free();
+	self.tokenizer = .{.source = data};
 
 	const allocator = self.arena.as_allocator();
 	var has_returned = false;
 
 	while (true) {
-		const no_effect_message = "statement has no effect";
+		self.tokenizer.skip(.newline);
 
-		tokenizer.skip(.newline);
+		switch (self.tokenizer.token orelse return) {
-
-		switch (tokenizer.token orelse return) {
 			.keyword_return => {
 				if (has_returned) {
-					return self.raise("multiple returns in function scope but expected only one");
+					return self.report("multiple returns in function scope but expected only one");
 				}
 
 				try self.statements.push_one(get_statement: {
-					tokenizer.step();
+					self.tokenizer.step();
 
-					if (!tokenizer.is_token_null_or(.newline)) {
+					if (!self.tokenizer.is_token_null_or(.newline)) {
-						break: get_statement .{.return_expression = try self.parse_expression(tokenizer)};
+						break: get_statement .{.return_expression = try self.parse_expression()};
 					}
 
-					if (!tokenizer.is_token_null_or(.newline)) {
+					if (!self.tokenizer.is_token_null_or(.newline)) {
-						return self.raise("unexpected token after return");
+						return self.report("unexpected token after return");
 					}
 
 					break: get_statement .return_nothing;
@@ -193,60 +204,64 @@ pub fn parse(self: *Self, tokenizer: *tokens.Tokenizer) ParseError!void {
 			},
 
 			.identifier => |identifier| {
-				tokenizer.step();
+				self.tokenizer.step();
 
-				switch (tokenizer.token orelse return self.raise(no_effect_message)) {
+				const no_effect_message = "statement has no effect";
-					.newline => return self.raise(no_effect_message),
+
+				switch (self.tokenizer.token orelse return self.report(no_effect_message)) {
+					.newline => return self.report(no_effect_message),
 
 					.symbol_equals => {
-						tokenizer.step();
+						self.tokenizer.step();
 
-						if (tokenizer.token == null) {
+						if (self.tokenizer.token == null) {
-							return self.raise("expected expression after `=`");
+							return self.report("expected expression after `=`");
 						}
 
 						try self.statements.push_one(.{
 							.set_local = .{
-								.expression = try self.parse_expression(tokenizer),
+								.expression = try self.parse_expression(),
 								.identifier = identifier,
 							},
 						});
 
-						if (!tokenizer.is_token_null_or(.newline)) {
+						if (!self.tokenizer.is_token_null_or(.newline)) {
-							return self.raise("unexpected token after assignment");
+							return self.report("unexpected token after assignment");
 						}
 					},
 
-					else => return self.raise("expected `=` after local"),
+					else => return self.report("expected `=` after local"),
 				}
 			},
 
 			.special_identifier => |identifier| {
-				tokenizer.step();
+				self.tokenizer.step();
 
-				switch (tokenizer.token orelse return self.raise(no_effect_message)) {
+				const missing_arguments_message = "system call is missing arguments";
-					.newline => return self.raise(no_effect_message),
+
+				switch (self.tokenizer.token orelse return self.report(missing_arguments_message)) {
+					.newline => return self.report(missing_arguments_message),
 
 					.symbol_paren_left => {
-						tokenizer.step();
+						self.tokenizer.step();
 
 						var expressions_list = Expression.List.make(allocator);
 
 						while (true) {
-							if (tokenizer.is_token(.symbol_paren_right)) {
+							if (self.tokenizer.is_token(.symbol_paren_right)) {
 								break;
 							}
 
-							try expressions_list.push_one(try self.parse_expression(tokenizer));
+							try expressions_list.push_one(try self.parse_expression());
 
-							switch (tokenizer.token orelse return self.raise("unexpected end after after `(`")) {
+							switch (self.tokenizer.token orelse return self.report("unexpected end after after `(`")) {
 								.symbol_comma => continue,
 								.symbol_paren_right => break,
-								else => return self.raise("expected `)` or argument after `(`"),
+								else => return self.report("expected `)` or argument after `(`"),
 							}
 						}
 
-						tokenizer.step();
+						self.tokenizer.step();
 
 						try self.statements.push_one(.{
 							.call_system = .{
@@ -256,11 +271,11 @@ pub fn parse(self: *Self, tokenizer: *tokens.Tokenizer) ParseError!void {
 						});
 					},
 
-					else => return self.raise("expected `=` after local"),
+					else => return self.report("expected `=` after local"),
 				}
 			},
 
-			else => return self.raise("invalid statement"),
+			else => return self.report("invalid statement"),
 		}
 	}
 }
@@ -281,67 +296,67 @@ const parse_expression = binary_operation_parser(parse_equality, &.{
 	.subtraction,
 });
 
-fn parse_factor(self: *Self, tokenizer: *tokens.Tokenizer) ParseError!Expression {
+fn parse_factor(self: *Self) ParseError!Expression {
 	const allocator = self.arena.as_allocator();
 
-	switch (tokenizer.token orelse return self.raise("expected operand after operator")) {
+	switch (self.tokenizer.token orelse return self.report("expected operand after operator")) {
 		.symbol_paren_left => {
-			tokenizer.skip(.newline);
+			self.tokenizer.skip(.newline);
 
-			if (tokenizer.token == null) {
+			if (self.tokenizer.token == null) {
-				return self.raise("expected an expression after `(`");
+				return self.report("expected an expression after `(`");
 			}
 
-			const expression = try self.parse_expression(tokenizer);
+			const expression = try self.parse_expression();
 
-			if (!tokenizer.is_token(.symbol_paren_right)) {
+			if (!self.tokenizer.is_token(.symbol_paren_right)) {
-				return self.raise("expected a closing `)` after expression");
+				return self.report("expected a closing `)` after expression");
 			}
 
-			tokenizer.step();
+			self.tokenizer.step();
 
 			return Expression{.grouped_expression = try coral.io.allocate_one(allocator, expression)};
 		},
 
 		.keyword_nil => {
-			tokenizer.step();
+			self.tokenizer.step();
 
 			return .nil_literal;
 		},
 
 		.keyword_true => {
-			tokenizer.step();
+			self.tokenizer.step();
 
 			return .true_literal;
 		},
 
 		.keyword_false => {
-			tokenizer.step();
+			self.tokenizer.step();
 
 			return .false_literal;
 		},
 
 		.number => |value| {
-			tokenizer.step();
+			self.tokenizer.step();
 
 			return Expression{.number_literal = value};
 		},
 
 		.string => |value| {
-			tokenizer.step();
+			self.tokenizer.step();
 
 			return Expression{.string_literal = value};
 		},
 
 		.special_identifier => |identifier| {
-			tokenizer.skip(.newline);
+			self.tokenizer.skip(.newline);
 
 			var expression_list = Expression.List.make(allocator);
 
 			while (true) {
-				switch (tokenizer.token orelse return self.raise("expected expression or `)` after `(`")) {
+				switch (self.tokenizer.token orelse return self.report("expected expression or `)` after `(`")) {
 					.symbol_paren_right => {
-						tokenizer.step();
+						self.tokenizer.step();
 
 						return Expression{
 							.call_system = .{
@@ -352,13 +367,13 @@ fn parse_factor(self: *Self, tokenizer: *tokens.Tokenizer) ParseError!Expression
 					},
 
 					else => {
-						try expression_list.push_one(try self.parse_expression(tokenizer));
+						try expression_list.push_one(try self.parse_expression());
 
-						switch (tokenizer.token orelse return self.raise("expected `,` or `)` after argument")) {
+						switch (self.tokenizer.token orelse return self.report("expected `,` or `)` after argument")) {
 							.symbol_comma => continue,
 
 							.symbol_paren_right => {
-								tokenizer.step();
+								self.tokenizer.step();
 
 								return Expression{
 									.call_system = .{
@@ -368,7 +383,7 @@ fn parse_factor(self: *Self, tokenizer: *tokens.Tokenizer) ParseError!Expression
 								};
 							},
 
-							else => return self.raise("expected `,` or `)` after argument"),
+							else => return self.report("expected `,` or `)` after argument"),
 						}
 					},
 				}
@@ -376,7 +391,7 @@ fn parse_factor(self: *Self, tokenizer: *tokens.Tokenizer) ParseError!Expression
 		},
 
 		.identifier => |identifier| {
-			tokenizer.step();
+			self.tokenizer.step();
 
 			return Expression{.get_local = identifier};
 		},
@@ -384,83 +399,83 @@ fn parse_factor(self: *Self, tokenizer: *tokens.Tokenizer) ParseError!Expression
 		.symbol_brace_left => {
 			var table_fields = Expression.NamedList.make(allocator);
 
-			tokenizer.skip(.newline);
+			self.tokenizer.skip(.newline);
 
 			while (true) {
-				switch (tokenizer.token orelse return self.raise("unexpected end of table literal")) {
+				switch (self.tokenizer.token orelse return self.report("unexpected end of table literal")) {
 					.symbol_brace_right => {
-						tokenizer.step();
+						self.tokenizer.step();
 
 						return Expression{.table_literal = table_fields};
 					},
 
 					.identifier => |identifier| {
-						tokenizer.skip(.newline);
+						self.tokenizer.skip(.newline);
 
-						if (!tokenizer.is_token(.symbol_equals)) {
+						if (!self.tokenizer.is_token(.symbol_equals)) {
-							return self.raise("expected `=` after identifier");
+							return self.report("expected `=` after identifier");
 						}
 
-						tokenizer.skip(.newline);
+						self.tokenizer.skip(.newline);
 
-						if (tokenizer.token == null) {
+						if (self.tokenizer.token == null) {
-							return self.raise("unexpected end after `=`");
+							return self.report("unexpected end after `=`");
 						}
 
 						try table_fields.push_one(.{
-							.expression = try self.parse_expression(tokenizer),
+							.expression = try self.parse_expression(),
 							.identifier = identifier,
 						});
 
-						switch (tokenizer.token orelse return self.raise("unexpected end of table")) {
+						switch (self.tokenizer.token orelse return self.report("unexpected end of table")) {
-							.symbol_comma => tokenizer.skip(.newline),
+							.symbol_comma => self.tokenizer.skip(.newline),
 
 							.symbol_brace_right => {
-								tokenizer.step();
+								self.tokenizer.step();
 
 								return Expression{.table_literal = table_fields};
 							},
 
-							else => return self.raise("expected `,` or `}` after expression"),
+							else => return self.report("expected `,` or `}` after expression"),
 						}
 					},
 
-					else => return self.raise("expected `}` or fields in table literal"),
+					else => return self.report("expected `}` or fields in table literal"),
 				}
 			}
 		},
 
 		.symbol_minus => {
-			tokenizer.skip(.newline);
+			self.tokenizer.skip(.newline);
 
-			if (tokenizer.token == null) {
+			if (self.tokenizer.token == null) {
-				return self.raise("expected expression after numeric negation (`-`)");
+				return self.report("expected expression after numeric negation (`-`)");
 			}
 
 			return Expression{
 				.unary_operation = .{
-					.expression = try coral.io.allocate_one(allocator, try self.parse_factor(tokenizer)),
+					.expression = try coral.io.allocate_one(allocator, try self.parse_factor()),
 					.operator = .numeric_negation,
 				},
 			};
 		},
 
 		.symbol_bang => {
-			tokenizer.skip(.newline);
+			self.tokenizer.skip(.newline);
 
-			if (tokenizer.token == null) {
+			if (self.tokenizer.token == null) {
-				return self.raise("expected expression after boolean negation (`!`)");
+				return self.report("expected expression after boolean negation (`!`)");
 			}
 
 			return Expression{
 				.unary_operation = .{
-					.expression = try coral.io.allocate_one(allocator, try self.parse_factor(tokenizer)),
+					.expression = try coral.io.allocate_one(allocator, try self.parse_factor()),
 					.operator = .boolean_negation,
 				},
 			};
 		},
 
-		else => return self.raise("unexpected token in expression"),
+		else => return self.report("unexpected token in expression"),
 	}
 }
 

source/ona/kym/tokens.zig

@@ -119,7 +119,7 @@ pub const Tokenizer = struct {
 				'#' => {
 					cursor += 1;
 
-					while (cursor < self.source.len and self.source[cursor] == '\n') {
+					while (cursor < self.source.len and self.source[cursor] != '\n') {
 						cursor += 1;
 					}
 				},

source/ona/ona.zig

@@ -11,13 +11,19 @@ const heap = @import("./heap.zig");
 const kym = @import("./kym.zig");
 
 fn kym_handle_errors(info: kym.ErrorInfo) void {
+	app.log_fail(info.message);
+
 	var remaining_frames = info.frames.len;
 
+	if (remaining_frames != 0) {
+		app.log_fail("stack trace:");
+
 		while (remaining_frames != 0) {
 			remaining_frames -= 1;
 
 			app.log_fail(info.frames[remaining_frames].name);
 		}
+	}
 }
 
 fn kym_log_info(env: *kym.RuntimeEnv) kym.RuntimeError!?*kym.RuntimeRef {
@@ -62,6 +68,10 @@ pub fn run_app(file_access: file.Access) void {
 			.name = "log_info",
 			.caller = kym.Caller.from(kym_log_info),
 		},
+		.{
+			.name = "log_warn",
+			.caller = kym.Caller.from(kym_log_warn),
+		},
 		.{
 			.name = "log_fail",
 			.caller = kym.Caller.from(kym_log_fail),