External Higher Order Functions

[FynnMazurkiewicz]

Hey everyone! 😊

I'm trying to use higher order functions.
I created a higher-order function outside of the interpreter and exposed it to the sandbox.
However, this fails because the higher order function receives the psuedoFunction and therefore can't call it (TypeError: fn is not a function).

A minimal test case:

var myCode = 'wrapper(function(){});';
var initFunc = function(interpreter, scope) {
    var wrapper = function(fn) {
        fn();
    };
    interpreter.setProperty(scope, 'wrapper',
        interpreter.createNativeFunction(wrapper));
};
var myInterpreter = new Interpreter(myCode, initFunc);
myInterpreter.run();

I couldn't find any examples or documentation on how to handle this.
Sandboxed higher order functions work fine, of course.

Not sure if this is intended behaviour, but I would be more than thankful for any leads.

[NeilFraser]

Yes, this is a limitation of the interpreter, it is really hard for external JavaScript to initiate a callback into the interpreter. The solution is to move the higher order function into the interpreted code.

Check out Array.prototype.map. This higher order function takes a function as an argument. To achieve this the map function is written as a polyfill. See the examples from line 869 to line 1046. There are a few more examples if you search for "this.polyfills_.push".

Feel free to reopen if you need more help.