On 11/11/2020 17:59, Christoph M. Becker wrote:
In JavaScript, a named function expression is different to a function
declaration:
var fn = function foo() {console.log('blah')}
foo()
=> Uncaught ReferenceError: foo is not defined
vs.
function foo() {console.log('blah')}
foo()
=> blah
So the named function expression is still an anonymous function; the
label is only defined inside of the function body.
I think the key difference is that in JS, functions and variables occupy
the same namespace, so "function foo" and "var foo = function" mean
roughly the same thing. For the same reason, *inside* a named function
expression, it acts as though there is a local variable with the given name:
var fn = function foo() {console.log(typeof foo)};
fn();
// outputs 'function'
which actually makes it very similar to...
On 11/11/2020 18:37, David Rodrigues wrote:
My suggestion is to reuse the keyword `as` to set a variable that will
represent its own closure. It is more flexible once that we could choose
any name and reuse in nested closures. It is pretty similar to how SQL
works too.
function fn1() as $lambda1 {
return function() as $lambda2 use ($lambda1) {
return [ gettype($lambda1), gettype($lambda2) ];
};
}
I like this idea; it avoids reserving a magic variable name, but gives
all the flexibility of having the full Closure object available (having
a "constant" whose value was a Closure object would be somewhat odd).
To take Dan's example from the RFC, this would no longer have any surprises:
$fibonacci = function (int $n) as $fibonacci {
if ($n === 0) return 0;
if ($n === 1) return 1;
return $fibonacci($n-1) + $fibonacci($n-2);
};
$this_is_the_original_fibonacci = $fibonacci;
$fibonacci = function (int $n) { return rand(0, $n); };
echo $this_is_the_original_fibonacci(10). "\n";
The $fibonacci inside the closure would be a normal local variable,
which just happens to have the same name as the one outside, so
assigning to one would have no effect on the other.
Regards,
--
Rowan Tommins (né Collins)
[IMSoP]
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