FM / ice-9

/usr/share/guile/2.0/ice-9

Name	Size	Mode	Actions
and-let-star.scm	2593	0644	edit dl rm
binary-ports.scm	1921	0644	edit dl rm
boot-9.scm	154720	0644	edit dl rm
buffered-input.scm	4935	0644	edit dl rm
calling.scm	10790	0644	edit dl rm
channel.scm	5312	0644	edit dl rm
command-line.scm	18655	0644	edit dl rm
common-list.scm	9160	0644	edit dl rm
control.scm	4036	0644	edit dl rm
curried-definitions.scm	1829	0644	edit dl rm
debug.scm	1114	0644	edit dl rm
deprecated.scm	31993	0644	edit dl rm
documentation.scm	7432	0644	edit dl rm
eval-string.scm	2997	0644	edit dl rm
eval.scm	21354	0644	edit dl rm
expect.scm	5628	0644	edit dl rm
format.scm	76284	0644	edit dl rm
ftw.scm	24753	0644	edit dl rm
futures.scm	11186	0644	edit dl rm
gap-buffer.scm	10384	0644	edit dl rm
getopt-long.scm	16888	0644	edit dl rm
hash-table.scm	1813	0644	edit dl rm
hcons.scm	2614	0644	edit dl rm
history.scm	2343	0644	edit dl rm
i18n.scm	17778	0644	edit dl rm
iconv.scm	3735	0644	edit dl rm
lineio.scm	3941	0644	edit dl rm
list.scm	1319	0644	edit dl rm
local-eval.scm	9946	0644	edit dl rm
ls.scm	3275	0644	edit dl rm
mapping.scm	4955	0644	edit dl rm
match.scm	2045	0644	edit dl rm
match.upstream.scm	36459	0644	edit dl rm
networking.scm	3407	0644	edit dl rm
null.scm	1157	0644	edit dl rm
occam-channel.scm	7436	0644	edit dl rm
optargs.scm	16123	0644	edit dl rm
poe.scm	3382	0644	edit dl rm
poll.scm	6166	0644	edit dl rm
popen.scm	5806	0644	edit dl rm
posix.scm	2793	0644	edit dl rm
pretty-print.scm	16211	0644	edit dl rm
psyntax-pp.scm	166774	0644	edit dl rm
psyntax.scm	147118	0644	edit dl rm
q.scm	4297	0644	edit dl rm
quasisyntax.scm	5348	0644	edit dl rm
r4rs.scm	9645	0644	edit dl rm
r5rs.scm	1602	0644	edit dl rm
r6rs-libraries.scm	9164	0644	edit dl rm
rdelim.scm	7648	0644	edit dl rm
readline.scm	9786	0644	edit dl rm
receive.scm	1082	0644	edit dl rm
regex.scm	9084	0644	edit dl rm
runq.scm	8379	0644	edit dl rm
rw.scm	1047	0644	edit dl rm
safe-r5rs.scm	3814	0644	edit dl rm
safe.scm	1275	0644	edit dl rm
save-stack.scm	2197	0644	edit dl rm
scm-style-repl.scm	11986	0644	edit dl rm
serialize.scm	3859	0644	edit dl rm
session.scm	18143	0644	edit dl rm
slib.scm	1583	0644	edit dl rm
stack-catch.scm	1983	0644	edit dl rm
streams.scm	7488	0644	edit dl rm
string-fun.scm	8798	0644	edit dl rm
syncase.scm	1556	0644	edit dl rm
threads.scm	6388	0644	edit dl rm
time.scm	2088	0644	edit dl rm
top-repl.scm	2812	0644	edit dl rm
unicode.scm	1005	0644	edit dl rm
vlist.scm	22081	0644	edit dl rm
weak-vector.scm	1288	0644	edit dl rm

Edit: /usr/share/guile/2.0/ice-9/optargs.scm (16123B)

;;;; optargs.scm -- support for optional arguments
;;;;
;;;; 	Copyright (C) 1997, 1998, 1999, 2001, 2002, 2004, 2006, 2009, 2010, 2011 Free Software Foundation, Inc.
;;;;
;;;; This library is free software; you can redistribute it and/or
;;;; modify it under the terms of the GNU Lesser General Public
;;;; License as published by the Free Software Foundation; either
;;;; version 3 of the License, or (at your option) any later version.
;;;; 
;;;; This library is distributed in the hope that it will be useful,
;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;;; Lesser General Public License for more details.
;;;; 
;;;; You should have received a copy of the GNU Lesser General Public
;;;; License along with this library; if not, write to the Free Software
;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;;;;
;;;; Contributed by Maciej Stachowiak <mstachow@alum.mit.edu>

;;; Commentary:

;;; {Optional Arguments}
;;;
;;; The C interface for creating Guile procedures has a very handy
;;; "optional argument" feature. This module attempts to provide
;;; similar functionality for procedures defined in Scheme with
;;; a convenient and attractive syntax.
;;;
;;; exported macros are:
;;;   let-optional
;;;   let-optional*
;;;   let-keywords
;;;   let-keywords*
;;;   lambda*
;;;   define*
;;;   define*-public
;;;   defmacro*
;;;   defmacro*-public
;;;
;;;
;;; Summary of the lambda* extended parameter list syntax (brackets
;;; are used to indicate grouping only):
;;;
;;; ext-param-list ::= [identifier]* [#:optional [ext-var-decl]+]?
;;;   [#:key [ext-var-decl]+ [#:allow-other-keys]?]?
;;;   [[#:rest identifier]|[. identifier]]?
;;;
;;; ext-var-decl ::= identifier | ( identifier expression )
;;;
;;; The characters `*', `+' and `?' are not to be taken literally; they
;;; mean respectively, zero or more occurences, one or more occurences,
;;; and one or zero occurences.
;;;

;;; Code:

(define-module (ice-9 optargs)
  #:use-module (system base pmatch)
  #:re-export (lambda* define*)
  #:export (let-optional
            let-optional*
            let-keywords
            let-keywords*
            define*-public
            defmacro*
            defmacro*-public))

;; let-optional rest-arg (binding ...) . body
;; let-optional* rest-arg (binding ...) . body
;;   macros used to bind optional arguments
;;
;; These two macros give you an optional argument interface that is
;; very "Schemey" and introduces no fancy syntax. They are compatible
;; with the scsh macros of the same name, but are slightly
;; extended. Each of binding may be of one of the forms <var> or
;; (<var> <default-value>). rest-arg should be the rest-argument of
;; the procedures these are used from. The items in rest-arg are
;; sequentially bound to the variable namess are given. When rest-arg
;; runs out, the remaining vars are bound either to the default values
;; or to `#f' if no default value was specified. rest-arg remains
;; bound to whatever may have been left of rest-arg.
;;

(define (vars&inits bindings)
  (let lp ((bindings bindings) (vars '()) (inits '()))
    (syntax-case bindings ()
      (()
       (values (reverse vars) (reverse inits)))
      (((v init) . rest) (identifier? #'v)
       (lp #'rest (cons #'v vars) (cons #'init inits)))
      ((v . rest) (identifier? #'v)
       (lp #'rest (cons #'v vars) (cons #'#f inits))))))

(define-syntax let-optional
  (lambda (x)
    (syntax-case x ()
      ((_ rest-arg (binding ...) b0 b1 ...) (identifier? #'rest-arg)
       (call-with-values (lambda () (vars&inits #'(binding ...)))
         (lambda (vars inits)
           (with-syntax ((n (length vars))
                         (n+1 (1+ (length vars)))
                         (vars (append vars (list #'rest-arg)))
                         ((t ...) (generate-temporaries vars))
                         ((i ...) inits))
             #'(let ((t (lambda vars i))
                     ...)
                 (apply (lambda vars b0 b1 ...)
                        (or (parse-lambda-case '(0 n n n+1 #f '())
                                               (list t ...)
                                               rest-arg)
                            (error "sth" rest-arg)))))))))))

(define-syntax let-optional*
  (lambda (x)
    (syntax-case x ()
      ((_ rest-arg (binding ...) b0 b1 ...) (identifier? #'rest-arg)
       (call-with-values (lambda () (vars&inits #'(binding ...)))
         (lambda (vars inits)
           (with-syntax ((n (length vars))
                         (n+1 (1+ (length vars)))
                         (vars (append vars (list #'rest-arg)))
                         ((i ...) inits))
             #'(apply (lambda vars b0 b1 ...)
                      (or (parse-lambda-case '(0 n n n+1 #f '())
                                             (list (lambda vars i) ...)
                                             rest-arg)
                          (error "sth" rest-arg))))))))))

;; let-keywords rest-arg allow-other-keys? (binding ...) . body
;; let-keywords* rest-arg allow-other-keys? (binding ...) . body
;;   macros used to bind keyword arguments
;;
;; These macros pick out keyword arguments from rest-arg, but do not
;; modify it. This is consistent at least with Common Lisp, which
;; duplicates keyword args in the rest arg. More explanation of what
;; keyword arguments in a lambda list look like can be found below in
;; the documentation for lambda*.  Bindings can have the same form as
;; for let-optional. If allow-other-keys? is false, an error will be
;; thrown if anything that looks like a keyword argument but does not
;; match a known keyword parameter will result in an error.
;;

(define-syntax let-keywords
  (lambda (x)
    (syntax-case x ()
      ((_ rest-arg aok (binding ...) b0 b1 ...) (identifier? #'rest-arg)
       (call-with-values (lambda () (vars&inits #'(binding ...)))
         (lambda (vars inits)
           (with-syntax ((n (length vars))
                         (vars vars)
                         (ivars (generate-temporaries vars))
                         ((kw ...) (map symbol->keyword
                                        (map syntax->datum vars)))
                         ((idx ...) (iota (length vars)))
                         ((t ...) (generate-temporaries vars))
                         ((i ...) inits))
             #'(let ((t (lambda ivars i))
                     ...)
                 (apply (lambda vars b0 b1 ...)
                        (or (parse-lambda-case '(0 0 #f n aok ((kw . idx) ...))
                                               (list t ...)
                                               rest-arg)
                            (error "sth" rest-arg))))))))
      ((_ rest-arg aok (binding ...) b0 b1 ...)
       #'(let ((r rest-arg))
           (let-keywords r aok (binding ...) b0 b1 ...))))))

(define-syntax let-keywords*
  (lambda (x)
    (syntax-case x ()
      ((_ rest-arg aok (binding ...) b0 b1 ...) (identifier? #'rest-arg)
       (call-with-values (lambda () (vars&inits #'(binding ...)))
         (lambda (vars inits)
           (with-syntax ((n (length vars))
                         (vars vars)
                         ((kw ...) (map symbol->keyword
                                        (map syntax->datum vars)))
                         ((idx ...) (iota (length vars)))
                         ((i ...) inits))
             #'(apply (lambda vars b0 b1 ...)
                      (or (parse-lambda-case '(0 0 #f n aok ((kw . idx) ...))
                                             (list (lambda vars i) ...)
                                             rest-arg)
                          (error "sth" rest-arg)))))))
      ((_ rest-arg aok (binding ...) b0 b1 ...)
       #'(let ((r rest-arg))
           (let-keywords* r aok (binding ...) b0 b1 ...))))))

;; lambda* args . body
;;   lambda extended for optional and keyword arguments
;;
;; lambda* creates a procedure that takes optional arguments. These
;; are specified by putting them inside brackets at the end of the
;; paramater list, but before any dotted rest argument. For example,
;;   (lambda* (a b #:optional c d . e) '())
;; creates a procedure with fixed arguments a and b, optional arguments c
;; and d, and rest argument e. If the optional arguments are omitted
;; in a call, the variables for them are bound to `#f'.
;;
;; lambda* can also take keyword arguments. For example, a procedure
;; defined like this:
;;   (lambda* (#:key xyzzy larch) '())
;; can be called with any of the argument lists (#:xyzzy 11)
;; (#:larch 13) (#:larch 42 #:xyzzy 19) (). Whichever arguments
;; are given as keywords are bound to values.
;;
;; Optional and keyword arguments can also be given default values
;; which they take on when they are not present in a call, by giving a
;; two-item list in place of an optional argument, for example in:
;;   (lambda* (foo #:optional (bar 42) #:key (baz 73)) (list foo bar baz))
;; foo is a fixed argument, bar is an optional argument with default
;; value 42, and baz is a keyword argument with default value 73.
;; Default value expressions are not evaluated unless they are needed
;; and until the procedure is called.
;;
;; lambda* now supports two more special parameter list keywords.
;;
;; lambda*-defined procedures now throw an error by default if a
;; keyword other than one of those specified is found in the actual
;; passed arguments. However, specifying #:allow-other-keys
;; immediately after the keyword argument declarations restores the
;; previous behavior of ignoring unknown keywords. lambda* also now
;; guarantees that if the same keyword is passed more than once, the
;; last one passed is the one that takes effect. For example,
;;   ((lambda* (#:key (heads 0) (tails 0)) (display (list heads tails)))
;;    #:heads 37 #:tails 42 #:heads 99)
;; would result in (99 47) being displayed.
;;
;; #:rest is also now provided as a synonym for the dotted syntax rest
;; argument. The argument lists (a . b) and (a #:rest b) are equivalent in
;; all respects to lambda*. This is provided for more similarity to DSSSL,
;; MIT-Scheme and Kawa among others, as well as for refugees from other
;; Lisp dialects.

;; define* args . body
;; define*-public args . body
;;   define and define-public extended for optional and keyword arguments
;;
;; define* and define*-public support optional arguments with
;; a similar syntax to lambda*. Some examples:
;;   (define* (x y #:optional a (z 3) #:key w . u) (display (list y z u)))
;; defines a procedure x with a fixed argument y, an optional agument
;; a, another optional argument z with default value 3, a keyword argument w,
;; and a rest argument u.
;;
;; Of course, define*[-public] also supports #:rest and #:allow-other-keys
;; in the same way as lambda*.

(define-syntax define*-public
  (lambda (x)
    (syntax-case x ()
      ((_ (id . args) b0 b1 ...)
       #'(define-public id (lambda* args b0 b1 ...)))
      ((_ id val) (identifier? #'id)
       #'(define-public id val)))))

;; defmacro* name args . body
;; defmacro*-public args . body
;;   defmacro and defmacro-public extended for optional and keyword arguments
;;
;; These are just like defmacro and defmacro-public except that they
;; take lambda*-style extended paramter lists, where #:optional,
;; #:key, #:allow-other-keys and #:rest are allowed with the usual
;; semantics. Here is an example of a macro with an optional argument:
;;   (defmacro* transmogrify (a #:optional b)

(define-syntax defmacro*
  (lambda (x)
    (syntax-case x ()
      ((_ id args doc b0 b1 ...) (string? (syntax->datum #'doc))
       #'(define-macro id doc (lambda* args b0 b1 ...)))
      ((_ id args b0 b1 ...) 
       #'(define-macro id #f (lambda* args b0 b1 ...))))))
(define-syntax-rule (defmacro*-public id args b0 b1 ...)
  (begin
    (defmacro* id args b0 b1 ...)
    (export-syntax id)))

;;; Support for optional & keyword args with the interpreter.
(define *uninitialized* (list 'uninitialized))
(define (parse-lambda-case spec inits args)
  (pmatch spec
    ((,nreq ,nopt ,rest-idx ,nargs ,allow-other-keys? ,kw-indices)
     (define (req args prev tail n)
       (cond
        ((zero? n)
         (if prev (set-cdr! prev '()))
         (let ((slots-tail (make-list (- nargs nreq) *uninitialized*)))
           (opt (if prev (append! args slots-tail) slots-tail)
                slots-tail tail nopt inits)))
        ((null? tail)
         #f) ;; fail
        (else
         (req args tail (cdr tail) (1- n)))))
     (define (opt slots slots-tail args-tail n inits)
       (cond
        ((zero? n)
         (rest-or-key slots slots-tail args-tail inits rest-idx))
        ((null? args-tail)
         (set-car! slots-tail (apply (car inits) slots))
         (opt slots (cdr slots-tail) '() (1- n) (cdr inits)))
        (else
         (set-car! slots-tail (car args-tail))
         (opt slots (cdr slots-tail) (cdr args-tail) (1- n) (cdr inits)))))
     (define (rest-or-key slots slots-tail args-tail inits rest-idx)
       (cond
        (rest-idx
         ;; it has to be this way, vars are allocated in this order
         (set-car! slots-tail args-tail)
         (if (pair? kw-indices)
             (permissive-keys slots (cdr slots-tail) args-tail inits)
             (rest-or-key slots (cdr slots-tail) '() inits #f)))
        ((pair? kw-indices)
         ;; fail early here, because once we're in keyword land we throw
         ;; errors instead of failing
         (and (or (null? args-tail) rest-idx (keyword? (car args-tail)))
              (key slots slots-tail args-tail inits)))
        ((pair? args-tail)
         #f) ;; fail
        (else
         slots)))
     (define (permissive-keys slots slots-tail args-tail inits)
       (cond
        ((null? args-tail)
         (if (null? inits)
             slots
             (begin
               (if (eq? (car slots-tail) *uninitialized*)
                   (set-car! slots-tail (apply (car inits) slots)))
               (permissive-keys slots (cdr slots-tail) '() (cdr inits)))))
        ((not (keyword? (car args-tail)))
         (permissive-keys slots slots-tail (cdr args-tail) inits))
        ((and (keyword? (car args-tail))
              (pair? (cdr args-tail))
              (assq-ref kw-indices (car args-tail)))
         => (lambda (i)
              (list-set! slots i (cadr args-tail))
              (permissive-keys slots slots-tail (cddr args-tail) inits)))
        ((and (keyword? (car args-tail))
              (pair? (cdr args-tail))
              allow-other-keys?)
         (permissive-keys slots slots-tail (cddr args-tail) inits))
        (else (scm-error 'keyword-argument-error #f "Unrecognized keyword"
                         '() args-tail))))
     (define (key slots slots-tail args-tail inits)
       (cond
        ((null? args-tail)
         (if (null? inits)
             slots
             (begin
               (if (eq? (car slots-tail) *uninitialized*)
                   (set-car! slots-tail (apply (car inits) slots)))
               (key slots (cdr slots-tail) '() (cdr inits)))))
        ((not (keyword? (car args-tail)))
         (if rest-idx
             ;; no error checking, everything goes to the rest..
             (key slots slots-tail '() inits)
             (scm-error 'keyword-argument-error #f "Invalid keyword"
                        '() args-tail)))
        ((and (keyword? (car args-tail))
              (pair? (cdr args-tail))
              (assq-ref kw-indices (car args-tail)))
         => (lambda (i)
              (list-set! slots i (cadr args-tail))
              (key slots slots-tail (cddr args-tail) inits)))
        ((and (keyword? (car args-tail))
              (pair? (cdr args-tail))
              allow-other-keys?)
         (key slots slots-tail (cddr args-tail) inits))
        (else (scm-error 'keyword-argument-error #f "Unrecognized keyword"
                         '() args-tail))))
     (let ((args (list-copy args)))
       (req args #f args nreq)))
    (else (error "unexpected spec" spec))))

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