Moritz Heidkamp <mor...@twoticketsplease.de> writes:
> find attached a suggested addition to miscmacros
Attached a syntax-rules based implementation which is much easier to
grok. I am leaning towards putting those into a separate egg now though.
Index: miscmacros.scm
===================================================================
--- miscmacros.scm (revision 25904)
+++ miscmacros.scm (working copy)
@@ -9,7 +9,8 @@
define-optionals define-parameter define-enum
ignore-values ignore-errors
ecase
- define-syntax-rule)
+ define-syntax-rule
+ -> ->* ->> ->>*)
(import scheme)
;; No effect -- caller must import these manually.
@@ -303,4 +304,32 @@
clauses ...
(else (error "no valid case" val))))
+(define-syntax ->
+ (syntax-rules ()
+ ((_ x) x)
+ ((_ x (y z ...) rest ...)
+ (-> (y x z ...) rest ...))))
+
+(define-syntax ->>
+ (syntax-rules ()
+ ((_ x) x)
+ ((_ x (y ...) rest ...)
+ (->> (y ... x) rest ...))))
+
+(define-syntax ->*
+ (syntax-rules ()
+ ((_ x) x)
+ ((_ x (y z ...) rest ...)
+ (->* (receive args x
+ (apply y (append args (list z ...))))
+ rest ...))))
+
+(define-syntax ->>*
+ (syntax-rules ()
+ ((_ x) x)
+ ((_ x (y z ...) rest ...)
+ (->>* (receive args x
+ (apply y (append (list z ...) args)))
+ rest ...))))
+
)
Index: tests/run.scm
===================================================================
--- tests/run.scm (revision 0)
+++ tests/run.scm (working copy)
@@ -0,0 +1,22 @@
+(use test srfi-1 miscmacros)
+
+(test 1 (-> 99 (/ 11) (/ 9)))
+
+(test '(1 2 3 4)
+ (->* (values 1 2)
+ (list 3)
+ (append '(4))))
+
+(test 7 (-> 10 (- 3)))
+(test -7 (->> 10 (- 3)))
+
+(test 9 (->> 1 (+ 2) (* 3)))
+
+(test 9 (->> '(1 2 3)
+ (map add1)
+ (fold + 0)))
+
+(test '((foo . 100) (bar . 200))
+ (->>* (values '(foo bar) '(100 200))
+ (map cons)))
+
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