parenscript-devel November 2009

parenscript-devel@common-lisp.net

5 participants
9 discussions

[parenscript-devel] Implicit return for function bodies
by Vladimir Sedach 28 Dec '09

28 Dec '09

Hello, Many of you have been asking for this for a long time, and based on feedback (as well as my own experience) the lack of this feature has been the biggest cause of bugs in PS code, so it's with a bit of joy that I just pushed out a patch to add implicit returns to PS functions (including lambdas and flet/labels) to the repository just now. Please try it out and report any bugs you find! Thank you, Vladimir

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Re: [parenscript-devel] How to generate element[i].childNodes[0].nodeValue
by Wout Perquin 03 Dec '09

03 Dec '09

On Tue, 2009-11-24 at 19:42 +0000, Wout Perquin wrote: > Hi, > I would like to generate : > "var value = element[i].childNode[0].nodeValue" > in one sentence. > > Currently I have a workaround : > (ps:ps > (let ((foo (aref element i)) > (value (slot-value (aref foo.child-nodes 0)'node-value))))) > which renders : > "var foo = element[i]; > var value = foo.childNodes[0].nodeValue;" > > Is there another more direct way ? > Thanks in advance. > Wout Perquin

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Re: [parenscript-devel] Implicit return for function bodies
by sblist＠me.com 02 Dec '09

02 Dec '09

Hi Vladimir, Another tricky area for implicit return is in IF/WHEN/UNLESS. What happens currently is that when a conditional is in an expression place (such as after a RETURN statement), it is converted into a ternary expression. This works when the branches of the conditional contain only assignments and expressions, but you get a syntax error if there is a switch, for, or while statement in the branch body. I'm not sure how to handle this in the general expression-place scenario, but it seems like implicit return should handle all of the conditional branches -- something like this: (ps (lambda () (when x y))) => "function () { return x ? y : null; };" becomes: (ps (lambda () (when x y))) => "if (x) { return y; };" or perhaps: (ps (lambda () (when x y))) => "if (x) { return y; } else { return null; };" - Scott On 2009-11-04, at 12:57 PM, Vladimir Sedach wrote: > Hello, > > Many of you have been asking for this for a long time, and based on > feedback (as well as my own experience) the lack of this feature has > been the biggest cause of bugs in PS code, so it's with a bit of joy > that I just pushed out a patch to add implicit returns to PS functions > (including lambdas and flet/labels) to the repository just now. Please > try it out and report any bugs you find! > > Thank you, > Vladimir > > _______________________________________________ > parenscript-devel mailing list > parenscript-devel(a)common-lisp.net > http://common-lisp.net/cgi-bin/mailman/listinfo/parenscript-devel

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[parenscript-devel] Multiple value calls
by Red Daly 26 Nov '09

26 Nov '09

Hi Parenscripters, As far as I can tell, multiple-value function calls are a unique feature of lisp. I would like the ability to perform multiple-value calls in Parenscript but I don't know if a sane solution exists or not. Can anyone come up with a scheme for returning multiple values that translates well to Javascript? Ideally such a scheme would not introduce much overhead for usual functions that do not use or return multiple values (though perhaps setting some sort of global MV flag might be inexpensive enough). Functions that return multiple values should also only appear to return a single value when called by a function that expects only one return value (including native javascript functions). (defun paren-mv-returner () (return (values 1 2 3))) => function parenMvReturner() { /* do some magic with the values 2 and 3 */ return 1; } // one implementation might be var mv = undefined; function parenMvReturner() { mv = [2, 3]; return 1; } // this scheme needs to adjust the return statement of every function so it might not be sufficient // consider this other function function parenMySingleReturner () { var x = parenMvReturner();

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[parenscript-devel] Of interest to those interested in Clojure
by Vladimir Sedach 12 Nov '09

12 Nov '09

Here's an interesting project that does something like Parenscript for CL, but for Clojure: http://github.com/arohner/scriptjure Vladimir

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Re: [parenscript-devel] Implicit return for function bodies
by sblist＠me.com 05 Nov '09

05 Nov '09

Hi Vladimir, Thanks a lot for doing this work, it'll be seriously great to have implicit return! On 2009-11-04, at 12:57 PM, Vladimir Sedach wrote: > Hello, > > Many of you have been asking for this for a long time, and based on > feedback (as well as my own experience) the lack of this feature has > been the biggest cause of bugs in PS code, so it's with a bit of joy > that I just pushed out a patch to add implicit returns to PS functions > (including lambdas and flet/labels) to the repository just now. Please > try it out and report any bugs you find! The first one I encountered was to do with the special return handling for case/switch. 1) The return special form assumes the wrong switch/case structure for these statements, it should be: (switch-case what &rest clauses) rather than: (switch-case what clauses) ...in both the destructing code and the reconstruction of the clauses, having been updated with the return statement. 2) The return special form needs to handle break forms in switch/case; rather than wrapping a break statement, it should remove it and wrap the previous expression in the return statement. Here's the (incorrect) output that I'm getting after having fixed the first issue: (ps (lambda () (case 1 (0 1) (otherwise 2)))) "function () { switch (1) { case 0: 1; return break; default: return 2; }; };" I think we want to see: "function () { switch (1) { case 0: return 1; default: return 2; }; };" - Scott

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[parenscript-devel] [PATCH] Make NIL the value (the last form in enclosing PROGN) of a LOOP macro with no default accumulator.
by sblist＠me.com 05 Nov '09

05 Nov '09

Hi Vladimir, You'll probably want to handle FOR, WHILE separately in the RETURN special form, but I think this works for our purposes with the existing support for PROGN. Generally, I think that the implicit return mechanism should try its utmost to avoid generating JS syntax errors. - Scott --- src/lib/ps-loop.lisp | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/src/lib/ps-loop.lisp b/src/lib/ps-loop.lisp index 7272247..8a383a4 100644 --- a/src/lib/ps-loop.lisp +++ b/src/lib/ps-loop.lisp @@ -325,4 +325,4 @@ ,@(initially loop) ,main ,@(finally loop)) - ,@(when (default-accum-var loop) `((return ,(default-accum- var loop))))))) + ,(aif (default-accum-var loop) it nil)))) -- 1.6.5.2

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[parenscript-devel] Weirdness around symbol translation
by Daniel Gackle 05 Nov '09

05 Nov '09

These guys do this: JS> (ps a!) "abang;" JS> (ps a!!) "abangbang;" JS> (ps a%) "apercent;" JS> (ps a%%) "apercentpercent;" But these guys do this: JS> (ps a+) "aplus;" JS> (ps a++) ";" JS> (ps a*) "astar;" JS> (ps a**) ";" I'm sure this has something to do with translation of *NAMES-LIKE-THIS* and +NAMES-LIKE-THIS+. But presumably those should be special cases where * and + are truly delimiting the name?

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[parenscript-devel] Bug: function call doesn't work with symbol macros
by Daniel Gackle 01 Nov '09

01 Nov '09

(ps (symbol-macrolet ((fake real)) (fake 123))) => "fake(123);"

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parenscript-devel November 2009