macro of macros

pull/2/head
Matthew Butterick 10 years ago
parent 8552b9f8da
commit 05c5b37316

@ -1,21 +1,44 @@
#lang racket/base
(require (for-syntax racket/base))
(provide macro-map)
(provide macro-map macro-for-each)
(define-syntax (macro-map stx)
(syntax-case stx ()
[(_ macro-name (list item0))
#'(cons
(macro-name item0) '())]
[(_ macro-name (list item0 items ...))
#'(cons
(macro-name item0)
(macro-map macro-name (list items ...)))]))
(define-syntax-rule (make-mappy-macro mappy-macro-name joining-proc ending-value)
(define-syntax mappy-macro-name
(syntax-id-rules ()
;; convert quote form into list form
[(_ macro-name (quote (items (... ...))))
(mappy-macro-name macro-name (list items (... ...)))]
;; catch this case first, because it would also match the next one
[(_ macro-name (list item0))
(joining-proc
(macro-name item0) ending-value)]
[(_ macro-name (list item0 items (... ...)))
(joining-proc
(macro-name item0)
(mappy-macro-name macro-name (list items (... ...))))])))
(define-syntax-rule (add x)
(+ 1 x))
(make-mappy-macro macro-for-each begin (void))
(make-mappy-macro macro-map cons '())
(define-syntax-rule (add pair)
(+ (car pair) (cdr pair)))
;; this matches first case - why?
(macro-for-each add (list (cons 12 20)))
;(macro-map add (list 24 25 30))
;(macro-map add '(24 25 30))
;(macro-map-old add (list 24 25 30))
;(macro-for-each add '(24 25 30))
(macro-map add (list 24 25 30))
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