[parenscript-devel] "let over lambda" seems buggy
hi, all, I found that (create "fn" (let ((x)) (lambda () x))) compiles to { 'fn' : (x = null, function () { return x; }) } wherein the variable x may conflict with a variable with the same name outside this code. How may avoid this? How may I achieve "let over lambda" closure effect as in common lisp? Thanks.
Hi Actually the above code is correct. You can also use: - either (let (x) (create "fn" (lambda () x))) - or (create "x" nil "fn" (lambda () x))) depending on the JS semantics you want to get. vsevolod On Thu, Oct 13, 2011 at 8:40 AM, Canhua <dreameration@gmail.com> wrote:
hi, all, I found that (create "fn" (let ((x)) (lambda () x)))
compiles to { 'fn' : (x = null, function () { return x; }) }
wherein the variable x may conflict with a variable with the same name outside this code. How may avoid this? How may I achieve "let over lambda" closure effect as in common lisp?
Thanks.
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
actually what I want to achieve is something like this: (create "fn_1" (let ((x)) #'(lambda () x)) "fn_2" (let ((x)) #'(lambda () x))) and I expected these two "x" are lexical-scope separate and so independent from each other. However the compiled js code doesn't work as I expected. On Thu, Oct 13, 2011 at 2:51 PM, Vsevolod Dyomkin <vseloved@gmail.com> wrote:
Hi Actually the above code is correct. You can also use: - either (let (x) (create "fn" (lambda () x))) - or (create "x" nil "fn" (lambda () x))) depending on the JS semantics you want to get. vsevolod
On Thu, Oct 13, 2011 at 8:40 AM, Canhua <dreameration@gmail.com> wrote:
hi, all, I found that (create "fn" (let ((x)) (lambda () x)))
compiles to { 'fn' : (x = null, function () { return x; }) }
wherein the variable x may conflict with a variable with the same name outside this code. How may avoid this? How may I achieve "let over lambda" closure effect as in common lisp?
Thanks.
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
I suggest, that you first consider, how would you do that in JS. You'll need to wrap that in functions: { 'fn_1' : (function () { var x = 1; return function () { return x; } }) (), 'fn_2' : (function () { var x = 2; return function () { return x; } }) () } Now let's think, how this can be done in Parenscript?.. PS. But the most important question is: why do you need to create a single function, that closes over a "private" variable, as part of an object? Isn't it equivalent to just coding the value of the variable inside the function? vsevolod On Thu, Oct 13, 2011 at 10:05 AM, Canhua <dreameration@gmail.com> wrote:
actually what I want to achieve is something like this: (create "fn_1" (let ((x)) #'(lambda () x)) "fn_2" (let ((x)) #'(lambda () x))) and I expected these two "x" are lexical-scope separate and so independent from each other. However the compiled js code doesn't work as I expected.
On Thu, Oct 13, 2011 at 2:51 PM, Vsevolod Dyomkin <vseloved@gmail.com> wrote:
Hi Actually the above code is correct. You can also use: - either (let (x) (create "fn" (lambda () x))) - or (create "x" nil "fn" (lambda () x))) depending on the JS semantics you want to get. vsevolod
On Thu, Oct 13, 2011 at 8:40 AM, Canhua <dreameration@gmail.com> wrote:
hi, all, I found that (create "fn" (let ((x)) (lambda () x)))
compiles to { 'fn' : (x = null, function () { return x; }) }
wherein the variable x may conflict with a variable with the same name outside this code. How may avoid this? How may I achieve "let over lambda" closure effect as in common lisp?
Thanks.
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
Thank you for your suggestion. I should work. And I may also use a variable name for "x" that isn't possible to conflict (use gensym). So, yes, there are ways to work around this issue. But I learnt that "let over lambda" in parenscript is different from that in common lisp. Is that right? The reason why I want need this is that I have to pass the whole object as argument to a library function. Many js libraries seem like to use object as configuration argument. On Thu, Oct 13, 2011 at 3:13 PM, Vsevolod Dyomkin <vseloved@gmail.com> wrote:
I suggest, that you first consider, how would you do that in JS. You'll need to wrap that in functions: { 'fn_1' : (function () { var x = 1; return function () { return x; } }) (), 'fn_2' : (function () { var x = 2; return function () { return x; } }) () } Now let's think, how this can be done in Parenscript?.. PS. But the most important question is: why do you need to create a single function, that closes over a "private" variable, as part of an object? Isn't it equivalent to just coding the value of the variable inside the function? vsevolod
On Thu, Oct 13, 2011 at 10:05 AM, Canhua <dreameration@gmail.com> wrote:
actually what I want to achieve is something like this: (create "fn_1" (let ((x)) #'(lambda () x)) "fn_2" (let ((x)) #'(lambda () x))) and I expected these two "x" are lexical-scope separate and so independent from each other. However the compiled js code doesn't work as I expected.
On Thu, Oct 13, 2011 at 2:51 PM, Vsevolod Dyomkin <vseloved@gmail.com> wrote:
Hi Actually the above code is correct. You can also use: - either (let (x) (create "fn" (lambda () x))) - or (create "x" nil "fn" (lambda () x))) depending on the JS semantics you want to get. vsevolod
On Thu, Oct 13, 2011 at 8:40 AM, Canhua <dreameration@gmail.com> wrote:
hi, all, I found that (create "fn" (let ((x)) (lambda () x)))
compiles to { 'fn' : (x = null, function () { return x; }) }
wherein the variable x may conflict with a variable with the same name outside this code. How may avoid this? How may I achieve "let over lambda" closure effect as in common lisp?
Thanks.
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
On Thu, Oct 13, 2011 at 10:25 AM, Canhua <dreameration@gmail.com> wrote:
Thank you for your suggestion. I should work. And I may also use a variable name for "x" that isn't possible to conflict (use gensym). So, yes, there are ways to work around this issue. But I learnt that "let over lambda" in parenscript is different from that in common lisp. Is that right?
Yes, because Parenscript's target is JavaScript the semantics of many operations is different from Common Lisp's.
The reason why I want need this is that I have to pass the whole object as argument to a library function. Many js libraries seem like to use object as configuration argument.
In this case you probably don't need a closure as object's "member" function. vsevolod
On Thu, Oct 13, 2011 at 3:13 PM, Vsevolod Dyomkin <vseloved@gmail.com> wrote:
I suggest, that you first consider, how would you do that in JS. You'll need to wrap that in functions: { 'fn_1' : (function () { var x = 1; return function () { return x; } }) (), 'fn_2' : (function () { var x = 2; return function () { return x; } }) () } Now let's think, how this can be done in Parenscript?.. PS. But the most important question is: why do you need to create a single function, that closes over a "private" variable, as part of an object? Isn't it equivalent to just coding the value of the variable inside the function? vsevolod
On Thu, Oct 13, 2011 at 10:05 AM, Canhua <dreameration@gmail.com> wrote:
actually what I want to achieve is something like this: (create "fn_1" (let ((x)) #'(lambda () x)) "fn_2" (let ((x)) #'(lambda () x))) and I expected these two "x" are lexical-scope separate and so independent from each other. However the compiled js code doesn't work as I expected.
On Thu, Oct 13, 2011 at 2:51 PM, Vsevolod Dyomkin <vseloved@gmail.com> wrote:
Hi Actually the above code is correct. You can also use: - either (let (x) (create "fn" (lambda () x))) - or (create "x" nil "fn" (lambda () x))) depending on the JS semantics you want to get. vsevolod
On Thu, Oct 13, 2011 at 8:40 AM, Canhua <dreameration@gmail.com>
wrote:
hi, all, I found that (create "fn" (let ((x)) (lambda () x)))
compiles to { 'fn' : (x = null, function () { return x; }) }
wherein the variable x may conflict with a variable with the same
name
outside this code. How may avoid this? How may I achieve "let over lambda" closure effect as in common lisp?
Thanks.
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net
http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net
http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
I see two bugs in Parenscript here: 1. Parenscript should wrap forms like (create "fn" (let ((x)) (lambda () x))) compiled at the toplevel in a lambda to prevent capture of global variables. So the code should look like: (ps (create "fn" (let ((x)) (lambda () x)))) => "(function () { var x; return { 'fn' : (x = null, function () { return x; }) }; })();" 2. The other bug I see is that even if you wrap the create in a lambda right now, the same variable x will be captured: (ps (lambda () (create "fn" (let ((x)) (lambda () x)) "fn2" (let ((x 2)) (lambda () x))))) => "(function () { var x; return { 'fn' : (x = null, function () { return x; }), 'fn2' : (x = 2, function () { return x; }) }; });" This is obviously wrong behavior. I'm going to work on some fixes. Vladimir On Thu, Oct 13, 2011 at 3:25 AM, Canhua <dreameration@gmail.com> wrote:
Thank you for your suggestion. I should work. And I may also use a variable name for "x" that isn't possible to conflict (use gensym). So, yes, there are ways to work around this issue. But I learnt that "let over lambda" in parenscript is different from that in common lisp. Is that right?
The reason why I want need this is that I have to pass the whole object as argument to a library function. Many js libraries seem like to use object as configuration argument.
On Thu, Oct 13, 2011 at 3:13 PM, Vsevolod Dyomkin <vseloved@gmail.com> wrote:
I suggest, that you first consider, how would you do that in JS. You'll need to wrap that in functions: { 'fn_1' : (function () { var x = 1; return function () { return x; } }) (), 'fn_2' : (function () { var x = 2; return function () { return x; } }) () } Now let's think, how this can be done in Parenscript?.. PS. But the most important question is: why do you need to create a single function, that closes over a "private" variable, as part of an object? Isn't it equivalent to just coding the value of the variable inside the function? vsevolod
On Thu, Oct 13, 2011 at 10:05 AM, Canhua <dreameration@gmail.com> wrote:
actually what I want to achieve is something like this: (create "fn_1" (let ((x)) #'(lambda () x)) "fn_2" (let ((x)) #'(lambda () x))) and I expected these two "x" are lexical-scope separate and so independent from each other. However the compiled js code doesn't work as I expected.
On Thu, Oct 13, 2011 at 2:51 PM, Vsevolod Dyomkin <vseloved@gmail.com> wrote:
Hi Actually the above code is correct. You can also use: - either (let (x) (create "fn" (lambda () x))) - or (create "x" nil "fn" (lambda () x))) depending on the JS semantics you want to get. vsevolod
On Thu, Oct 13, 2011 at 8:40 AM, Canhua <dreameration@gmail.com> wrote:
hi, all, I found that (create "fn" (let ((x)) (lambda () x)))
compiles to { 'fn' : (x = null, function () { return x; }) }
wherein the variable x may conflict with a variable with the same name outside this code. How may avoid this? How may I achieve "let over lambda" closure effect as in common lisp?
Thanks.
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
I pushed fixes for both problems 1 and 2. Try them out. As a consequence, most Parenscript expressions should also now "work" (return a value, and not introduce spurious global variables) at the top-level, which should make it much easier to do Parenscript REPLs. Vladimir On Mon, Dec 12, 2011 at 7:16 PM, Vladimir Sedach <vsedach@gmail.com> wrote:
I see two bugs in Parenscript here:
1. Parenscript should wrap forms like (create "fn" (let ((x)) (lambda () x))) compiled at the toplevel in a lambda to prevent capture of global variables. So the code should look like:
(ps (create "fn" (let ((x)) (lambda () x)))) => "(function () { var x; return { 'fn' : (x = null, function () { return x; }) }; })();"
2. The other bug I see is that even if you wrap the create in a lambda right now, the same variable x will be captured:
(ps (lambda () (create "fn" (let ((x)) (lambda () x)) "fn2" (let ((x 2)) (lambda () x))))) =>
"(function () { var x; return { 'fn' : (x = null, function () { return x; }), 'fn2' : (x = 2, function () { return x; }) }; });"
This is obviously wrong behavior. I'm going to work on some fixes.
Vladimir
On Thu, Oct 13, 2011 at 3:25 AM, Canhua <dreameration@gmail.com> wrote:
Thank you for your suggestion. I should work. And I may also use a variable name for "x" that isn't possible to conflict (use gensym). So, yes, there are ways to work around this issue. But I learnt that "let over lambda" in parenscript is different from that in common lisp. Is that right?
The reason why I want need this is that I have to pass the whole object as argument to a library function. Many js libraries seem like to use object as configuration argument.
On Thu, Oct 13, 2011 at 3:13 PM, Vsevolod Dyomkin <vseloved@gmail.com> wrote:
I suggest, that you first consider, how would you do that in JS. You'll need to wrap that in functions: { 'fn_1' : (function () { var x = 1; return function () { return x; } }) (), 'fn_2' : (function () { var x = 2; return function () { return x; } }) () } Now let's think, how this can be done in Parenscript?.. PS. But the most important question is: why do you need to create a single function, that closes over a "private" variable, as part of an object? Isn't it equivalent to just coding the value of the variable inside the function? vsevolod
On Thu, Oct 13, 2011 at 10:05 AM, Canhua <dreameration@gmail.com> wrote:
actually what I want to achieve is something like this: (create "fn_1" (let ((x)) #'(lambda () x)) "fn_2" (let ((x)) #'(lambda () x))) and I expected these two "x" are lexical-scope separate and so independent from each other. However the compiled js code doesn't work as I expected.
On Thu, Oct 13, 2011 at 2:51 PM, Vsevolod Dyomkin <vseloved@gmail.com> wrote:
Hi Actually the above code is correct. You can also use: - either (let (x) (create "fn" (lambda () x))) - or (create "x" nil "fn" (lambda () x))) depending on the JS semantics you want to get. vsevolod
On Thu, Oct 13, 2011 at 8:40 AM, Canhua <dreameration@gmail.com> wrote:
hi, all, I found that (create "fn" (let ((x)) (lambda () x)))
compiles to { 'fn' : (x = null, function () { return x; }) }
wherein the variable x may conflict with a variable with the same name outside this code. How may avoid this? How may I achieve "let over lambda" closure effect as in common lisp?
Thanks.
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
_______________________________________________ parenscript-devel mailing list parenscript-devel@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel
participants (3)
-
Canhua -
Vladimir Sedach -
Vsevolod Dyomkin