combinators: Add on

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Luis Guilherme Coelho 2024-08-23 00:09:51 -03:00
parent d742a38a3f
commit 82ff5a9150
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1 changed files with 37 additions and 36 deletions

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@ -1,4 +1,5 @@
(define-module (radix combinators) (define-module (radix combinators)
#:use-module (ice-9 curried-definitions)
#:use-module (ice-9 match) #:use-module (ice-9 match)
#:export (all-of #:export (all-of
any-of any-of
@ -7,37 +8,36 @@
inclusive-disjoin inclusive-disjoin
flip flip
juxt juxt
on
partial partial
swap)) swap))
(define (all-of pred) (define* ((all-of pred) lst)
"Returns a procedure that takes a list LST and returns #t if every other "Returns a procedure that takes a list LST and returns #t if every other
element of LST satisfies PRED." element of LST satisfies PRED."
(lambda (lst) (null? (filter (negate pred) lst)))) (null? (filter (negate pred) lst)))
(define (any-of pred) (define* ((any-of pred) lst)
"Returns a procedure that takes a list LST and returns #t if any element of "Returns a procedure that takes a list LST and returns #t if any element of
LST satisfies PRED." LST satisfies PRED."
(lambda (lst)
(let loop ((lst lst)) (let loop ((lst lst))
(match (match
('() #f) ('() #f)
((head . tail) ((head . tail)
(cond ((pred head) #t) (cond ((pred head) #t)
(else (loop tail)))))))) (else (loop tail)))))))
(define (conjoin . predicates) (define* ((conjoin . predicates) args)
"Returns a procedure that is the conjuction of every predicate in PREDICATES. "Returns a procedure that is the conjuction of every predicate in PREDICATES.
The returned procedure takes an arbitrary number of arguments, and returns #t The returned procedure takes an arbitrary number of arguments, and returns #t
if these arguments satisfy every other predicate in PREDICATES." if these arguments satisfy every other predicate in PREDICATES."
(lambda args
(if (null? predicates) #t (if (null? predicates) #t
(match-let loop (((head-pred . tail-preds) predicates)) (match-let loop (((head-pred . tail-preds) predicates))
(cond ((null? tail-preds) (apply head-pred args)) (cond ((null? tail-preds) (apply head-pred args))
((apply head-pred args) (loop tail-preds)) ((apply head-pred args) (loop tail-preds))
(else #f)))))) (else #f)))))
(define (disjoin . predicates) (define* ((disjoin . predicates) args)
"Returns a procedure that is the disjunction of every predicate in PREDICATES. "Returns a procedure that is the disjunction of every predicate in PREDICATES.
The returned procedure takes an arbitrary number of arguments, and returns #t if The returned procedure takes an arbitrary number of arguments, and returns #t if
these arguments satisfy exactly one predicate in PREDICATES, and #f otherwise." these arguments satisfy exactly one predicate in PREDICATES, and #f otherwise."
@ -46,38 +46,39 @@ The returned procedure takes an arbitrary number of arguments, and returns #t if
((_) #t) ((_) #t)
(else #f)))) (else #f))))
(define (inclusive-disjoin . predicates) (define* ((inclusive-disjoin . predicates) args)
"Returns a procedure that is the inclusive disjunction of every predicate in "Returns a procedure that is the inclusive disjunction of every predicate in
PREDICATES. The returned procedure takes an arbitrary number of arguments, and PREDICATES. The returned procedure takes an arbitrary number of arguments, and
returns #t if these arguments satifsy at least one predicate in PREDICATES, and returns #t if these arguments satifsy at least one predicate in PREDICATES, and
#f otherwise." #f otherwise."
(lambda args
(if (null? predicates) #f (if (null? predicates) #f
(match-let loop (((head-pred . tail-preds) predicates)) (match-let loop (((head-pred . tail-preds) predicates))
(cond ((null? tail-preds) (apply head-pred args)) (cond ((null? tail-preds) (apply head-pred args))
((not (apply head-pred args)) (loop tail-preds)) ((not (apply head-pred args)) (loop tail-preds))
(else #f)))))) (else #f)))))
(define (partial proc . args) (define* ((partial proc . args) more-args)
"Returns a procedure that receives MORE-ARGS applies PROC to the list "Returns a procedure that receives MORE-ARGS applies PROC to the list
obtained by appending ARGS to MORE-ARGS." obtained by appending ARGS to MORE-ARGS."
(lambda more-args (apply proc (append args more-args)))) (apply proc (append args more-args)))
(define (flip proc) (define* ((flip proc) args)
"Returns a procedure that applies PROC to the reverse of ARGS." "Returns a procedure that applies PROC to the reverse of ARGS."
(lambda args (apply proc (reverse args)))) (apply proc (reverse args)))
(define (swap proc) (define* ((swap proc) arg1 arg2 . args)
"Returns a procedure that takes ARG1, ARG2 and optionally more args, and "Returns a procedure that takes ARG1, ARG2 and optionally more args, and
applies PROC to the list obtained by cons*ing ARG2 ARG1 to ARG2 to the list applies PROC to the list obtained by cons*ing ARG2 ARG1 to ARG2 to the list
of aditional arguments." of aditional arguments."
(lambda (arg1 arg2 . args) (apply proc arg2 arg1 args))
(apply proc arg2 arg1 args)))
(define (juxt proc . more-procs) (define* ((juxt proc . more-procs) args)
"Returns a procedure that is the juxtaposition of it's argument procedures. "Returns a procedure that is the juxtaposition of it's argument procedures.
The returned procedure takes a variable number of args, and returns a list The returned procedure takes a variable number of args, and returns a list
containing the result of applying each procedure to the args (left-to-right)." containing the result of applying each procedure to the args (left-to-right)."
(lambda args
(map (partial (flip apply) args) (map (partial (flip apply) args)
(cons proc more-procs)))) (cons proc more-procs)))
(define* ((on proc1 proc2) . args)
"Returns a procedure that applies PROC1 to the to the map of PROC2 to ARGS."
(apply proc1 (map proc2 args)))