Cannot call functions returned by functions

[phillipskevin]

This template:

  stache("<p>{{foo()()}}</p>")({
    foo() {
      return () => {
        return "Hello"
      }
    }
  });

...gives this error:

Uncaught Error: Unable to understand expression foo()()

[phillipskevin]

This makes things like <p on:click="scope.find('foo')()"> impossible.

[justinbmeyer]

Step 1

make a test for getting the expression AST built right. Example test:

can-stache/test/expression-test.js

Line 81 in 83191d3

test("expression.ast - everything", function(){

An expression like foo()() results in:

{
	type: "Call",
	children: [
		{
			type: "Call",
			method: {type: "Lookup", "@foo"},
			children: []
		}
	]
}

Step 2

Update the parse to create this.

That will happen somewhere around here:

can-stache/src/expression.js

Line 446 in 83191d3

throw new Error("Unable to understand expression "+tokens.join(''));

Step 3

This ast can hydrate correctly into nested Call expressions.

This hydration happens around here:

can-stache/src/expression.js

Line 278 in 83191d3

else if(ast.type === "Call" || ast.type === "Helper") {

Might want to write a test for hydration. Example:

can-stache/test/expression-test.js

Line 582 in 83191d3

exprData = expression.parse("equal(foo(), [bar])");

Step 4

Make sure the Call expression type can actually do what you need. (test first)

Testing foo(1)(2) might look something like:

expr = new expression.Call(
                new expression.Call({
                  new expression.Lookup("bar"),
                  [ new expression.Literal(1) ]
                }),
	       [ new expression.Literal(2) ]
	);
	compute = expr.value(
		new Scope(
			new SimpleMap({foo: function( one){ return function( two ){ ... } } })
		)
	);

Might need to change

can-stache/expressions/call.js

Line 66 in 83191d3

var method = this.methodExpr.value(scope, { proxyMethods: false });

to make this work, but I think it will already.

[chasenlehara]

@Mattchewone Can this be closed now?

[Mattchewone]

Yup still haven't got the hang of having the MR's close issues :(