At one point I had this implemented using try-catch unless Parenscript's
compiler could prove (rather naively) that the return-from clause was always
executed. I am usually way behind the official branch, and I'm not sure if
my changes ever made it in, and if they did if this case is a bug. Anyway
it would do something like
function foo() {
try {
var bar = function () {
throw { 'ps-return-foo341' : 42 };
};
bar(); }
catch (e) {
if ('ps-return-foo341' in e)
return e['ps-return-foo341'];
else
throw e;
};
verbose, but it should always work. other try-catch tricks allow lisp-style
conditions, which I detailed in a post in this list within the year. in
case of group interest the relevant code is available at
https://github.com/gonzojive/paren-psos and
https://github.com/gonzojive/parenscript
Viva Parenscript!
Red
On Tue, Jun 7, 2011 at 11:40 PM, <[email protected]> wrote:
> Hi,
>
> I was wondering if the BLOCK/RETURN-FROM feature in PS intends
> to support the following case:
>
> (ps (defun foo ()
> (flet ((bar () (return-from foo 42)))
> (bar))))
>
> =>
>
> WARNING: Returning from unknown block FOO
> "function foo() {
> var bar = function () {
> return 42;
> };
> return bar();
> };"
>
> In order to try and get around the warning, I tried this:
>
> (ps (defun baz ()
> (block foo
> (flet ((bar () (return-from foo 42)))
> (bar)))))
>
> =>
>
> WARNING: Returning from unknown block FOO
> "function baz() {
> var bar = function () {
> return 42;
> };
> return bar();
> };"
>
> but that didn't seem to work. Any ideas on how to achieve lexical
> return here?
>
> - Scott
>
>
> _______________________________________________
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> [email protected]
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>
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