Function parse_function

util/string/expression_parser.cpp:355–415

);

Error parse_function(Tokenizer &tokenizer, StdVector<UniquePtr<Node>> &operand_stack, Span<const Function> functions) {
	std::string_view fname;
	{
		// We'll replace the variable with a function call node
		UniquePtr<Node> top = pop(operand_stack);
		ZN_ASSERT(top->type == Node::VARIABLE);
		const VariableNode *node = static_cast<VariableNode *>(top.get());
		fname = node->name;
	}

	const Function *fn = find_function_by_name(fname, functions);
	if (fn == nullptr) {
		Error error;
		error.id = ERROR_UNKNOWN_FUNCTION;
		error.position = tokenizer.get_position();
		error.symbol = fname;
		return error;
	}

	UniquePtr<FunctionNode> fnode = make_unique_instance<FunctionNode>();
	fnode->function_id = fn->id;
	ZN_ASSERT(fn->argument_count < fnode->args.size());

	Token last_token;

	for (unsigned int arg_index = 0; arg_index < fn->argument_count; ++arg_index) {
		Result arg_result = parse_expression(tokenizer, true, functions, &last_token);

		if (arg_result.error.id != ERROR_NONE) {
			return arg_result.error;
		}

		if (arg_result.root == nullptr) {
			Error error;
			error.id = ERROR_EXPECTED_ARGUMENT;
			error.position = tokenizer.get_position();
			error.symbol = fname;
			return error;

		} else if (last_token.type == Token::PARENTHESIS_CLOSE && arg_index + 1 < fn->argument_count) {
			Error error;
			error.id = ERROR_TOO_FEW_ARGUMENTS;
			error.position = tokenizer.get_position();
			error.symbol = fname;
			return error;
		}

		fnode->args[arg_index] = std::move(arg_result.root);
	}

	if (last_token.type != Token::PARENTHESIS_CLOSE) {
		Error error;
		error.id = ERROR_TOO_MANY_ARGUMENTS;
		error.position = tokenizer.get_position();
		error.symbol = fname;
		return error;
	}