parenscript-devel November 2010

parenscript-devel@common-lisp.net

6 participants
7 discussions

[parenscript-devel] Patch: added JS label/break to PS
by Daniel Gackle 07 Dec '10

07 Dec '10

I just pushed a patch (authored by Scott) to implement JS's LABEL and BREAK in PS. (Note that this patch deprecates LABELED-FOR since you can get the same effect by combining LABEL and FOR. Was anybody using LABELED-FOR?) Here's an example: (label scope (foo) (when (bar) (break scope)) (blee)) => scope: { foo(); if (bar()) { break scope; }; blee(); }; I was astonished to discover recently that JS has supported this ability all along in the form of labeled statements and labeled breaks. I'd always assumed that to get explicit returns from an arbitrary scope, you'd have to resort to the ugly hack of muscling TRY/CATCH to do it, thinking that this was the closest JS counterpart. (See http://news.ycombinator.com/item?id=793092 for a thread in which several people believe this.) But it appears we were all wrong. What's not clear yet is how far this can be taken. Can you use it inside a nested local function to return immediately from the top-level function? That is one thing I've wanted for a long time. In the ideal case, LABEL/BREAK could be used as a base for implementing a proper BLOCK and RETURN-FROM in PS, something which we'd long believed to be impossible. One challenge is that in CL, RETURN-FROM can take a value, which becomes the value of BLOCK. In other words, BLOCK in CL is an expression while LABEL in JS is not. It seems, though, that most of this challenge has already been conquered with the development of implicit return in PS. The only thing you'd need to add is detecting when BLOCK is being used as an expression, declaring a gensymed variable and assigning whatever is happening inside BLOCK to that variable (much like implicit return already does with e.g. CASE), then put the variable in the expression position that BLOCK was in. It seems like this ought to work. It would also make things like this possible in PS: (1+ (case foo (:eleven 11) (:twelve 12))) Vladimir (and everybody), is the above clear? What do you think of it? Daniel

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[parenscript-devel] [PATCH] Define bit-shifting special forms >> and <<, and ASH as a macro.
by sblist＠me.com 06 Dec '10

06 Dec '10

I'm not sure how you feel about adding >> and << as special forms, but this seems to allow for a simpler implementation of ASH since it needs to do some higher-level transformations such as optimizing forms with a a constant COUNT argument along with avoiding multiple evaluation. Scott --- src/macros.lisp | 14 ++++++++++++++ src/package.lisp | 4 ++++ src/printer.lisp | 2 +- src/special-forms.lisp | 4 +++- 4 files changed, 22 insertions(+), 2 deletions(-) diff --git a/src/macros.lisp b/src/macros.lisp index 2014330..2c0c295 100644 --- a/src/macros.lisp +++ b/src/macros.lisp @@ -59,6 +59,20 @@ (define-ps-symbol-macro pi (getprop *math '*pi*)) +(defpsmacro ash (integer count) + (let ((count (ps-macroexpand count))) + (cond ((and (numberp count) (> count 0)) `(<< ,integer ,count)) + ((numberp count) `(>> ,integer ,(- count))) + ((complex-js-expr? count) + (let ((count-var (ps-gensym))) + `(let ((,count-var ,count)) + (if (> ,count-var 0) + (<< ,integer ,count-var) + (>> ,integer (- ,count-var)))))) + (t `(if (> ,count 0) + (<< ,integer ,count) + (>> ,integer (- ,count))))))) + ;;; Types (defpsmacro stringp (x) diff --git a/src/package.lisp b/src/package.lisp index 7921a37..92922e7 100644 --- a/src/package.lisp +++ b/src/package.lisp @@ -99,6 +99,10 @@ #:logxor #:lognot + #:ash + #:>> + #:<< + #:* #:/ #:rem diff --git a/src/printer.lisp b/src/printer.lisp index 73df146..5f119b7 100644 --- a/src/printer.lisp +++ b/src/printer.lisp @@ -169,7 +169,7 @@ vice-versa.") (defprinter js:post-- (x) (ps-print x)"--") -(defprinter (js:+ js:- js:* js:/ js:% js:&& js:\|\| js:& js:\| js:-= js:+= js:*= js:/= js:%= js:^ js:&= js:^= js:\|= js:= js:== js:=== js:!== js:in js:!= js:> js:>= js:< js:<=) +(defprinter (js:+ js:- js:* js:/ js:% js:&& js:\|\| js:& js:\| js:-= js:+= js:*= js:/= js:%= js:^ js:&= js:^= js:\|= js:= js:== js:=== js:!== js:in js:!= js:> js:>= js:< js:<= js:<< js:>>) (&rest args) (loop for (arg . remaining) on args do (print-op-argument op arg) diff --git a/src/special-forms.lisp b/src/special-forms.lisp index 6633b2f..5ca7a52 100644 --- a/src/special-forms.lisp +++ b/src/special-forms.lisp @@ -25,7 +25,9 @@ logior js:\| logxor js:^ lognot js:~ - ;; todo: ash for shifts + + >> js:>> + << js:<< throw js:throw array js:array -- 1.7.2.1

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[parenscript-devel] Support for case-sensitive symbols (backwards compatible)
by Vladimir Sedach 22 Nov '10

22 Nov '10

Hello everyone, At the suggestion of Matthias Benkard (http://stackoverflow.com/questions/1597355/why-are-parenscript-functions-ch…) I've added support for READTABLE-CASE :invert ed case-sensitive symbols to Parenscript. This change works automatically if your code is loaded with readtable-case :invert and the symbol contains mixed case, and should be backwards-compatible with the old mangling convention otherwise. Note that if your symbol names contain special characters (like *$#& etc) and is mixed case, the symbol is name mangled using the old convention. This means you can stop writing things like (encode-u-r-i-component foo-bar) and start writing things like (encodeURIComponent fooBar). I recommend using the named-readtables library to manage readtable state for your projects: http://common-lisp.net/project/named-readtables/ Happy hacking, Vladimir

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[parenscript-devel] parenscript usage
by Lucian Branescu 11 Nov '10

11 Nov '10

Hello.I'm thinking of using parenscript for my dissertation project. However, I'm a lisp newbie and I can't figure out how to compile a file. There is no README on the website or in the tarball.Could someone please please give me a hand?Thanks.

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[parenscript-devel] NESTING-DEPTH crashes on improper lists
by sblist＠me.com 09 Nov '10

09 Nov '10

This causes compilations of forms like the following to fail: (ps (defun foo (a) (when a (destructuring-bind (b . c) bar (list b c))))) => TYPE-ERROR Backtrace: 0: (NESTING-DEPTH (B . C)) 1: (NESTING-DEPTH (DESTRUCTURING-BIND (B . C) BAR (LIST B C))) 2: (NESTING-DEPTH (PROGN (DESTRUCTURING-BIND (B . C) BAR (LIST B C)))) 3: (NESTING-DEPTH (IF A (PROGN (DESTRUCTURING-BIND (B . C) BAR (LIST B C)))))

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[parenscript-devel] in-package and Parenscript compilation
by Alessio Stalla 06 Nov '10

06 Nov '10

Greetings, I'm approaching Parenscript and I must say I'm really impressed by this library. Kudos to the developers! But I find one thing missing: the Parenscript stream/file compiler does not understand in-package forms like the CL file compiler does; rather, it reads all the forms in the package which is current at the time it gets called. This makes it slightly inconvenient to compile Lisp files which need to be read in a certain package, and completely impossible to handle files which change *package* mid-file (which is generally not a good idea, but still it's possible in CL). I'm attaching a patch against src/compilation-interface.lisp to make the compiler behave like the CL one; comments are welcome. Regards, Alessio Stalla

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[parenscript-devel] Missing 'break' in CASE
by sblist＠me.com 06 Nov '10

06 Nov '10

It appears that some commit between ac408014 and b9dc8d1a (maybe 2f9fa1976a?) breaks the compilation of CASE forms in a function's tail position when some (but not all) branches in a body form contain a RETURN. PS> (ps (defun foo () (case x ("bar" (if y (return t) nil)) ("baz" nil)))) "function foo() { switch (x) { case 'bar': if (y) { return true; }; //----------------- missing break; here case 'baz': return null; }; };" Scott

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parenscript-devel November 2010