>> How do you define "non-method"?
>
> A function that is not invoked as method. Right now, the same kind of
> construct is used for both true functions and methods. I’m proposing a new
> construct (similar to the distinction that Python makes): a function that
> does not have an implicit |this| parameter.
Hm, you've lost me... Your proposal seems to have several possible
interpretations:
a) A compile-time error at the definition site for a function that will ever be
invoked as a function. This requires the ability to predict the future, which
turns out to be kinda hard. ;-P
b) A compile-time error at the definition site for a function that is not
defined inside of an object. This would be way too restrictive; programmers
rightfully use the ability to define a function and then put it into objects
afterwards.
function m(x, y, z) { ... this ... }
obj1.m = obj2.m = m;
or even
obj.m = function(x, y, z) { ... this ... }
c) At runtime, a function invoked as a non-method gets a |this|-binding of
*undefined*. This is already the semantics of ES5 strict and therefore Harmony.
d) At runtime, a function invoked as a non-method gets a dynamic ReferenceError
if it tries to refer to |this|. This would just be kind of obnoxious, I think,
since if the function wants to test whether it's been called as a non-method it
has to do something like
let nonMethod = false;
try { eval("this") } catch (e) { nonMethod = true }
That seems unfortunate.
Dave
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