Re: [Chicken-users] help with implicit renaming macro
On Mon, Nov 11, 2013 at 09:36:48PM +0100, Peter Bex wrote: > On Mon, Nov 11, 2013 at 01:22:40PM -0701, Alan Post wrote: > > I'd like to rewrite this macro as an implicit renaming > > macro, which seems to require that I traverse form and > > insert (inject arg1) wherever I find arg1, and to do > > the same for arg2. > > Hi Alan, > > Actually, you only need to inject the args where they > are introduced. This will cause them to be bound > unhygienically, which means they'll capture any local > variables with that same literal name. > > So unless I'm completely misunderstanding what you're > trying to do, this will suffice: > > (define-syntax do-output > (ir-macro-transformer > (lambda (e i c) > `(lambda (#!key ,(i 'arg1) ,(i 'arg2)) > (list ,@(cdr e)) > > > I do not otherwise need to transform the symbolic > > expression bound to output. Is there some idiomatic > > way to traverse a tree and perform a set of replacement > > operations on matching leaves? > > SSAX has "foldts" which can fold over trees, but I think > it's overkill to load an XML library just to transform your > macros :) > > Finally, you might want to take a look at some of Juergen Lorenz's > eggs, they provide some tools to deal with low-level macros a bit > more conveniently. > Aha, I missed the quote to the inject parameter, got an error about arg1, and assumed it was happening during expansion to report an unbound variable. pebkac. This does indeed work, fantastic. Really stellar feature, ir-macros. I have the most experience with defmacro, and it took me some time to come to terms with define-syntax/syntax-rules, though the vast majority of my macros fit easily and comfortably in that rubric. This was the first time in a long while I've wanted to do something more than simple transformation. I appreciate your guidance here! -a -- my personal website: http://c0redump.org/ ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
Re: [Chicken-users] help with implicit renaming macro
On Mon, Nov 11, 2013 at 01:22:40PM -0701, Alan Post wrote: > I'd like to rewrite this macro as an implicit renaming > macro, which seems to require that I traverse form and > insert (inject arg1) wherever I find arg1, and to do > the same for arg2. Hi Alan, Actually, you only need to inject the args where they are introduced. This will cause them to be bound unhygienically, which means they'll capture any local variables with that same literal name. So unless I'm completely misunderstanding what you're trying to do, this will suffice: (define-syntax do-output (ir-macro-transformer (lambda (e i c) `(lambda (#!key ,(i 'arg1) ,(i 'arg2)) (list ,@(cdr e)) > I do not otherwise need to transform the symbolic > expression bound to output. Is there some idiomatic > way to traverse a tree and perform a set of replacement > operations on matching leaves? SSAX has "foldts" which can fold over trees, but I think it's overkill to load an XML library just to transform your macros :) Finally, you might want to take a look at some of Juergen Lorenz's eggs, they provide some tools to deal with low-level macros a bit more conveniently. Cheers, Peter -- http://www.more-magic.net ___ Chicken-users mailing list Chicken-users@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-users
[Chicken-users] help with implicit renaming macro
I have a routine with several input arguments and one
output argument. I want to write a macro to wrap my
output argument such that I can pass the results of
my input arguments to my output argument. (See below)
I have this working with an explicit renaming macro,
but this is overkill. I could find myself capturing
variables other than my input arguments.
I'd like to rewrite this macro as an implicit renaming
macro, which seems to require that I traverse form and
insert (inject arg1) wherever I find arg1, and to do
the same for arg2.
I do not otherwise need to transform the symbolic
expression bound to output. Is there some idiomatic
way to traverse a tree and perform a set of replacement
operations on matching leaves?
(define (doit #!key arg1 arg2 output)
(output arg1: arg1 arg2: arg2))
; er-macro-transformer works, but it might capture
; more than arg1, arg2. Can I rewrite this to
; explicitely inject arg1 and arg2?
;
(define-syntax do-output
(er-macro-transformer
(lambda (form rename compare?)
`(lambda (#!key arg1 arg2)
(list ,@(cdr form))
>>> (doit arg1: "hello"
arg2: "world"
output: (do-output arg1 arg2))
=> ("hello world")
Thank you,
-Alan
--
my personal website: http://c0redump.org/
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