March 2010 - parenscript-devel - mailman3.common-lisp.net

[parenscript-devel] Lexical scoping bug
by Daniel Gackle 21 Apr '10

21 Apr '10

Just ran across this one: (ps (let ((abc (@ x :abc))) (funcall abc))) => "var abc901 = x.abc; abc();" Daniel

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[parenscript-devel] Bug with ==
by Daniel Gackle 11 Mar '10

11 Mar '10

(let ((x 10) (y 10) (z 10)) (= x y z)) is true Common Lisp, but the PS equivalent... var x = 10; var y = 10; var z = 10; x == y == z; ... is false. The left operand of the second == is actually x==y, which evalutes to true, and true==z of course is false. An equivalent in CL might be: (equal (equal x y) z) Perverse side note: the above example doesn't work if you assign 1 to the variables because in JS, the following is true: 1 == true I didn't know this. JS still manages to shock me sometimes. Daniel

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[parenscript-devel] A PS version of NCONC
by Daniel Gackle 09 Mar '10

09 Mar '10

I needed a destructive append to a JS array, so I wrote this version of NCONC for PS. It's primitive, but does what I need. (defun nconc (arr &rest arrs) (when (and arr (> (length arr) 0)) (loop :for other :in arrs :when (and other (> (length other) 0)) :do ((@ arr :splice :apply) arr (append (list (length arr) (length other)) other)))) arr) I suppose this would naturally go in some kind of runtime library for PS. (We have quite a few utility functions that might belong there, in fact.) But I don't think there is one anymore. Should there be? Daniel

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[parenscript-devel] The next frontier?
by Daniel Gackle 01 Mar '10

01 Mar '10

Congratulations on the new release! This seems like a good time to ask: what (if any) are the next significant things that could and should be added to Parenscript? Put differently, what CL constructs are there that (a) haven't been tackled yet, and (b) have a reasonable mapping to JS? The latter is important to preserve the goals of efficient, readable, debuggable JS. Any suggestions? I nominate backquote/comma. At least at a 50,000 foot level, it seems like the sort of thing PS could do, and it's pretty obvious that it would be useful. Daniel

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