Update specs: Disallow programs where function declarations do not appear at the top of their block scope

[martin-henz]

See #40

[openorclose]

Should we still keep this?

#54 (comment)

As per the discussion there and the suggestion by yyc, we would treat function declarations like let/const declarations, and only hoist the identifier up but not the definition.

So

a();
function a() {
  return 1;
}

and

display(a);
const a = 1;

would result in both throwing the same error about a being not defined in Source.

This would continue to allow the following pattern, allowing function declarations anywhere before it is called:

function step1() {
  return 1;
}
step1();
function step2() {
  return 2;
}
step2();

And we would not need this restriction anymore.

[martin-henz]

How about changing the restriction as follows:

Functions must not be called before their corresponding function declaration is evaluated.

This way, peeps cannot make use of the "hoisting" of function declarations, and we don't need to detect the problem in our implementation. Programs where this rule is violated give proper error messages, indicating that the program does not belong to Source.

[martin-henz]

Case closed?

[thomastanck]

Functions must not be called before their corresponding function declaration is evaluated.

I think that's good. It fits nicely with our current implementation and also plays well with JS.

[martin-henz]

handled by PR: 136 and 39