skyra-project / alestra Goto Github PK

There are many plans for the new parser and we should investigate the fastest path. At this moment, the code is parsed like if it were evaluated with eval(), then it's validated and run. When somebody mistypes a method or does not provide enough arguments (or arguments are invalid type), they are currently detected during validation, this comes as a performance cost because it takes a while to parse all methods in a long chain.

I propose making the parser a generator method and call it from the Evaluator class similarly to this (consider PARSE be the generator method that parses everything):

const canvas = new Canvas(Number(result[1]), Number(result[2]));
let breakChain = null;

for (const [method, args] of PARSE(code)) {
	if (breakChain) {
		throw new MethodParseError(`The CanvasConstructor.prototype.${breakChain} call was not chainable.`);
	}
	if (!(method in Canvas.prototype)) {
		throw new MethodParseError(`The method ${method} does not exist.`);
	}

	if (this.methods.has(method)) {
		if (canvas[method](...await this.methods.get(method).validate(args)) !== canvas) breakChain = method;
	} else {
		throw new MethodParseError(`The method ${method} is blocked.`);
	}
}

That way we can throw during parsing instead of waiting for everything to be parser and then validate.