;;;
;;; procutil.scm - auxiliary procedure utilities.  to be autoloaded.
;;;
;;;   Copyright (c) 2000-2024  Shiro Kawai  <shiro@acm.org>
;;;
;;;   Redistribution and use in source and binary forms, with or without
;;;   modification, are permitted provided that the following conditions
;;;   are met:
;;;
;;;   1. Redistributions of source code must retain the above copyright
;;;      notice, this list of conditions and the following disclaimer.
;;;
;;;   2. Redistributions in binary form must reproduce the above copyright
;;;      notice, this list of conditions and the following disclaimer in the
;;;      documentation and/or other materials provided with the distribution.
;;;
;;;   3. Neither the name of the authors nor the names of its contributors
;;;      may be used to endorse or promote products derived from this
;;;      software without specific prior written permission.
;;;
;;;   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
;;;   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
;;;   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
;;;   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
;;;   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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;;;   TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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;;;

(define-module gauche.procutil
  (export compose .$ complement flip swap
          pa$ map$ for-each$ apply$
          count$ fold$ fold-right$ reduce$ reduce-right$
          filter$ partition$ remove$ find$ find-tail$
          any$ every$ delete$ member$ assoc$
          any-pred every-pred
          arity procedure-arity-includes?
          <arity-at-least> arity-at-least? arity-at-least-value
          source-code source-location disasm
          ;; for the backward compatibility
          port-fold port-fold-right port-for-each port-map
          ))

(select-module gauche.procutil)

;; Combinator utilities -----------------------------------------

(define (pa$ fn . args)                  ;partial apply
  (^ more-args (apply fn (append args more-args))))

(define (compose . fns)
  (cond [(null? fns) values]
        [(null? (cdr fns)) (car fns)]
        [(null? (cddr fns))
         (^ args (call-with-values (^[] (apply (cadr fns) args)) (car fns)))]
        [else (compose (car fns) (apply compose (cdr fns)))]))

(define .$ compose)                     ;experimental

(define (compose$ f) (pa$ compose f))

;; SRFI-235
(define (complement fn)
  (case (arity fn) ;; some optimization
    [(0) (^[] (not (fn)))]
    [(1) (^[x] (not (fn x)))]
    [(2) (^[x y] (not (fn x y)))]
    [else (^ args (not (apply fn args)))]))

;; SRFI-235
(define (flip proc)
  (case (arity proc)
    [(0 1) proc]
    [(2) (^[x y] (proc y x))]
    [(3) (^[x y z] (proc z y x))]
    [else (^ args (apply proc (reverse args)))]))

;; SRFI-235
(define (swap proc)
  (case (arity proc)
    [(0 1) (error "procedure must take more than two arguments")]
    [(2) (^[x y] (proc y x))]
    [(3) (^[x y z] (proc y x z))]
    [else (^[x y . args] (apply proc y x args))]))

(define (map$ proc)      (pa$ map proc))
(define (for-each$ proc) (pa$ for-each proc))
(define (apply$ proc)    (pa$ apply proc))

;; partial evaluation version of SRFI-1 procedures
(define (count$ pred) (pa$ count pred))
(define (fold$ kons . maybe-knil)
  (^ lists (apply fold kons (append maybe-knil lists))))
(define (fold-right$ kons . maybe-knil)
  (^ lists (apply fold-right kons (append maybe-knil lists))))
(define (reduce$ f . maybe-ridentity)
  (^ args (apply reduce f (append maybe-ridentity args))))
(define (reduce-right$ f . maybe-ridentity)
  (^ args (apply reduce-right f (append maybe-ridentity args))))
(define (filter$ pred) (pa$ filter pred))
(define (partition$ pred) (pa$ partition pred))
(define (remove$ pred) (pa$ remove pred))
(define (find$ pred) (pa$ find pred))
(define (find-tail$ pred) (pa$ find-tail pred))
(define (any$ pred) (pa$ any pred))
(define (every$ pred) (pa$ every pred))
(define (delete$ x) (pa$ delete x))
(define (member$ x) (pa$ member x))
(define (assoc$ x) (pa$ assoc x))


(define (any-pred . preds)
  (^ args (let loop ([preds preds])
            (cond [(null? preds) #f]
                  [(apply (car preds) args)]
                  [else (loop (cdr preds))]))))

(define (every-pred . preds)
  (if (null? preds)
    (^ args #t)
    (^ args (let loop ([preds preds])
              (cond [(null? (cdr preds)) (apply (car preds) args)]
                    [(apply (car preds) args) (loop (cdr preds))]
                    [else #f])))))

;; Curryable procedures ------------------------------------

#|  disabled for now; see proc.c for the details.

(define %procedure-currying-set!        ;hidden
  (with-module gauche.internal %procedure-currying-set!))

(define-syntax curry-lambda
  (syntax-rules ()
    [(_ formals . body)
     (let1 var (lambda formals . body)
       (%procedure-currying-set! var #t)
       var)]))

(define-syntax define-curry
  (syntax-rules ()
    [(_ (name . formals) . body)
     (define name (curry-lambda formals . body))]))
|#

;; Procedure arity -----------------------------------------

(define-class <arity-at-least> ()
  ((value :init-keyword :value :init-value 0)))

(define-method write-object ((obj <arity-at-least>) port)
  (format port "#<arity-at-least ~a>" (ref obj 'value)))

(define (arity-at-least? x) (is-a? x <arity-at-least>))

(define (arity-at-least-value x)
  (check-arg arity-at-least? x)
  (ref x 'value))

(define (arity proc)
  (cond [(or (is-a? proc <procedure>) (is-a? proc <method>))
         (if-let1 clambda (case-lambda-decompose proc)
           (map (^[info] (if (cadr info)
                           (make <arity-at-least> :value (car info))
                           (car info)))
                clambda)
           (if (ref proc 'optional)
             (make <arity-at-least> :value (ref proc 'required))
             (ref proc 'required)))]
        [(is-a? proc <generic>) (map arity (ref proc 'methods))]
        [else (errorf "cannot get arity of ~s" proc)]))

(define (procedure-arity-includes? proc k)
  (let1 a (arity proc)
    (define (check a)
      (cond [(integer? a) (= a k)]
            [(arity-at-least? a) (>= k (arity-at-least-value a))]
            [else (errorf "implementation error in (procedure-arity-includes? ~s ~s)" proc k)]))
    (if (list? a)
      (any check a)
      (check a))))

;; source-code -------------------------------------------------
;; Take the source code and location from a procedure.
;;
;; Where is source code saved?
;;  (~ <compiled-code>'debug-info) -> definition -> source-info
;;  In case if the source is a result of macro expansion, the original
;;  source is attached in the 'original pair attribute of the source
;;  code.  The `source-code' procedure traces the very origin of the source
;;  (via compiled-code-definition).
;;  Note that precompiled closure doesn't have `definition' info, hence
;;  source code is not available.
;;
;; Where is source location saved?
;;  For SUBRs and precompiled closures: The stub generator and precompiler
;;  sets the procedure signature to the (~ <procedure>'info) slot.  The
;;  signature has 'source-info attribute attached.
;;  Other closures: They still have signature in 'info, but no source-info
;;  is attached.  Instead you should take the source code and then look
;;  at its source-info.

(define (source-code proc)
  (and (closure? proc)
       ((with-module gauche.internal compiled-code-definition)
        (closure-code proc))))

(define (source-location proc)
  (define (extract x)
    (and (pair? x)
         (pair-attribute-get x 'source-info #f)))
  (or (and (slot-exists? proc 'info)
           (extract (~ proc'info)))
      (extract (source-code proc))))

;; disassembler ------------------------------------------------
;; I'm not sure whether this should be here or not, but for the time being...

(define (disasm proc)
  (define dump (with-module gauche.internal vm-dump-code))
  (define (dump-case-lambda infos)
    (print "CASE-LAMBDA")
    (dolist [info infos]
      (apply [^(reqargs optarg proc)
               (when (closure? proc)
                 (if optarg
                   (print ";;; numargs > " reqargs)
                   (print ";;; numargs = " reqargs))
                 (dump (closure-code proc)))]
             info)))
  (cond
   [(closure? proc) (print "CLOSURE " proc)
    (dump (closure-code proc))
    (dolist [e ((with-module gauche.internal %closure-env->list) proc)]
      (let1 e (if (promise? e)
                (force e)
                e)
        (when (closure? e)
          (print "LIFTED CLOSURE " e)
          (dump (closure-code e)))))]
   [(is-a? proc <method>)
    (print "METHOD " proc)
    (cond [(method-code proc) => dump]
          [else (print "(defined in C)")])]
   [(is-a? proc <generic>)
    (print "GENERIC FUNCTION " proc)
    (dolist [m (~ proc'methods)]
      (print ">> method " m)
    (cond [(method-code m) => dump]
          [else (print "(defined in C)")]))]
   [(case-lambda-decompose proc) => dump-case-lambda]
   [else (print "Disassemble not applicable for " proc)])
  (values))

;; For the backward compatibility ------------------------------------
(select-module gauche)
(define port-fold generator-fold)
(define port-fold-right generator-fold-right)
(define port-for-each generator-for-each)
(define port-map generator-map)
