parenscript-devel

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373 discussions

[parenscript-devel] Evaluation of default values for keyword args
by Daniel Gackle 11 Jan '11

11 Jan '11

I'm glad to see the tighter code being generated for keyword arguments, but I'm afraid there's a problem. If a default value is provided, it is now being evaluated whether it's needed or not: (defun blah (&key (param (long-running-computation))) (foo param)) => function blah() { var param = longRunningComputation(); var _js10 = arguments.length; // ... return foo(param); }; Compare this to: (defun blah (&optional (param (long-running-computation))) (foo param)) => function blah(param) { if (param === undefined) { param = longRunningComputation(); }; return foo(param); }; I think the above keyword behavior is incorrect and the optionals have it right. Yet I like the fact that all the sludge of the "if variable remains undefined after sucking out the optional arguments then set it to null" sort has been removed. Is there a compromise? For example, could we do it the simpler way where the default value is a constant? Daniel

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[parenscript-devel] best practice for developing a JS-only HTML5 webapp?
by Jon Rosebaugh 11 Jan '11

11 Jan '11

As I said in the subject, I'm working on a JS-only (no server-side code) HTML5 webapp in Parenscript with jQuery. I have extensive JS experience, but I'm really new to Common Lisp. I wanted a setup where I could edit a Parenscript file, hit save, then hit refresh in my browser and immediately see the new code, just as if I were working in Javascript. I built a little server using Hunchentoot and cl-who that runs ps-compile-file on my parenscript source file as needed. This works fairly well, but maybe is not the best way to accomplish this. However, there's a problem; I wanted to use parenscript functions without the namespace, so I defined a package in serve.lisp that uses parenscript, then put (in-package :innkeeper) at the top of my parenscript file. This doesn't work properly in the 2.2 release of Parenscript (which is what Quicklisp provides). It _does_ work in the git repo version (as of commit 0e01e555f404a7dcb8befb7587288c38abf526c2), but it's annoying to not be able to use Quicklisp for everything. Once I have a release version I'll want to come up with some lisp program that compiles the parenscript to javascript, minifies it, and sticks it in an also-minified html file from cl-who, so the whole thing is compiled down to a single file. I'd appreciate any best-practice tips on that too. Just in case my description was unclear, here's what I think are the relevant bits. If needed, I can provide the entire files off-list. ; relevant bits of serve.lisp (defpackage "INNKEEPER" (:use "COMMON-LISP" "HUNCHENTOOT" "CL-WHO" "PARENSCRIPT") (:export :start-innserver :stop-innserver)) (in-package :innkeeper) (define-easy-handler (jsgen :uri "/innkeeper.js") () (setf (content-type*) "application/javascript") (ps-compile-file "/Users/jon/code/innkeeper/innkeeper.lisp")) ; beginning (and a few representative lines) of innkeeper.lisp (in-package :innkeeper) (defmacro immediate (&body body) `((lambda () ,@body))) (var *inn* (create setup (lambda () ((@ ($ "#top-tabs") tabs))))) (j-query #'(@ *inn* setup))

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[parenscript-devel] Over-aggressive expressification?
by Daniel Gackle 11 Dec '10

11 Dec '10

I noticed the JS for a function like this has changed: (defun blah () (when (some-condition) (foo) (bar) (baz))) It used to give this: function blah() { if (someCondition()) { foo(); bar(); return baz(); }; }; Now it produces this: function blah() { return someCondition() ? (foo(), barr(), baz()) : null; }; I think it's worth questioning whether this deviates too far from PS's goal of readable JS. I can give examples from our codebase where this approach produces very complex composite expressions that are quite unreadable. It doesn't bother me too much, since I understand what PS is doing and can always look at the source code. But it certainly sacrifices readability/debuggability. Too far? Daniel

2 1

[parenscript-devel] Syntax error: PS sometimes tries to treat throw like an expression
by Daniel Gackle 10 Dec '10

10 Dec '10

(defun blah () (let ((result (foo))) (unless (null result) (throw result)))) generates the syntactically incorrect: function blah() { var result = foo(); return result != null ? (throw result) : null; };

2 1

[parenscript-devel] Problem with BLOCK and RETURN-FROM
by Daniel Gackle 09 Dec '10

09 Dec '10

(1) The following expression generates the correct code: (defun blah () (λ () (foo 123))) But it also emits "Warning: Returning from unknown block NILBLOCK", which is undeserved. (2) It's not clear how to do explicit return from a lambda now. That is, (defun blah () (λ () (when (foo) (return 123)) ;; do some other stuff )) generates the same warning as above. Is this just a bug, or is it suggesting that one must explicitly declare a scope using (BLOCK NIL...) in order to do an explicit return warning-free? I'm hoping not the latter.

2 4

[parenscript-devel] Four PS bugs
by Daniel Gackle 07 Dec '10

07 Dec '10

Here are four problematic expressions. ;; crashes (defun foo () (let ((a (bar))))) ;; syntax err (defun foo () (let* ((a (bar))))) ;; returns nil (defun foo () "bar") ;; doesn't return nil (defun blah () (or (foo) (progn (bar) nil)))

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[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

1 0

[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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