-;;; srfi-16.scm --- case-lambda
-
-;; Copyright (C) 2001, 2002, 2006 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 2.1 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
-
-;;; Author: Martin Grabmueller
-
-;;; Commentary:
-
-;; Implementation of SRFI-16. `case-lambda' is a syntactic form
-;; which permits writing functions acting different according to the
-;; number of arguments passed.
-;;
-;; The syntax of the `case-lambda' form is defined in the following
-;; EBNF grammar.
-;;
-;; <case-lambda>
-;; --> (case-lambda <case-lambda-clause>)
-;; <case-lambda-clause>
-;; --> (<signature> <definition-or-command>*)
-;; <signature>
-;; --> (<identifier>*)
-;; | (<identifier>* . <identifier>)
-;; | <identifier>
-;;
-;; The value returned by a `case-lambda' form is a procedure which
-;; matches the number of actual arguments against the signatures in
-;; the various clauses, in order. The first matching clause is
-;; selected, the corresponding values from the actual parameter list
-;; are bound to the variable names in the clauses and the body of the
-;; clause is evaluated.
-
-;;; Code:
-
-(define-module (srfi srfi-16)
- :export-syntax (case-lambda))
-
-(cond-expand-provide (current-module) '(srfi-16))
-
-(define-macro (case-lambda . clauses)
-
- ;; Return the length of the list @var{l}, but allow dotted list.
- ;;
- (define (alength l)
- (cond ((null? l) 0)
- ((pair? l) (+ 1 (alength (cdr l))))
- (else 0)))
-
- ;; Return @code{#t} if @var{l} is a dotted list, @code{#f} if it is
- ;; a normal list.
- ;;
- (define (dotted? l)
- (cond ((null? l) #f)
- ((pair? l) (dotted? (cdr l)))
- (else #t)))
-
- ;; Return the expression for accessing the @var{index}th element of
- ;; the list called @var{args-name}. If @var{tail?} is true, code
- ;; for accessing the list-tail is generated, otherwise for accessing
- ;; the list element itself.
- ;;
- (define (accessor args-name index tail?)
- (if tail?
- (case index
- ((0) `,args-name)
- ((1) `(cdr ,args-name))
- ((2) `(cddr ,args-name))
- ((3) `(cdddr ,args-name))
- ((4) `(cddddr ,args-name))
- (else `(list-tail ,args-name ,index)))
- (case index
- ((0) `(car ,args-name))
- ((1) `(cadr ,args-name))
- ((2) `(caddr ,args-name))
- ((3) `(cadddr ,args-name))
- (else `(list-ref ,args-name ,index)))))
-
- ;; Generate the binding lists of the variables of one case-lambda
- ;; clause. @var{vars} is the (possibly dotted) list of variables
- ;; and @var{args-name} is the generated name used for the argument
- ;; list.
- ;;
- (define (gen-temps vars args-name)
- (let lp ((v vars) (i 0))
- (cond ((null? v) '())
- ((pair? v)
- (cons `(,(car v) ,(accessor args-name i #f))
- (lp (cdr v) (+ i 1))))
- (else `((,v ,(accessor args-name i #t)))))))
-
- ;; Generate the cond clauses for each of the clauses of case-lambda,
- ;; including the parameter count check, binding of the parameters
- ;; and the code of the corresponding body.
- ;;
- (define (gen-clauses l length-name args-name)
- (cond ((null? l) (list '(else (error "too few arguments"))))
- (else
- (cons
- `((,(if (dotted? (caar l)) '>= '=)
- ,length-name ,(alength (caar l)))
- (let ,(gen-temps (caar l) args-name)
- ,@(cdar l)))
- (gen-clauses (cdr l) length-name args-name)))))
-
- (let ((args-name (gensym))
- (length-name (gensym)))
- (let ((proc
- `(lambda ,args-name
- (let ((,length-name (length ,args-name)))
- (cond ,@(gen-clauses clauses length-name args-name))))))
- proc)))
-
-;;; srfi-16.scm ends here
+;;; srfi-16.scm --- case-lambda
+
+;; Copyright (C) 2001, 2002, 2006, 2009, 2014 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
+
+;;; Author: Martin Grabmueller
+
+;;; Commentary:
+
+;; Implementation of SRFI-16. `case-lambda' is a syntactic form
+;; which permits writing functions acting different according to the
+;; number of arguments passed.
+;;
+;; The syntax of the `case-lambda' form is defined in the following
+;; EBNF grammar.
+;;
+;; <case-lambda>
+;; --> (case-lambda <case-lambda-clause>)
+;; <case-lambda-clause>
+;; --> (<signature> <definition-or-command>*)
+;; <signature>
+;; --> (<identifier>*)
+;; | (<identifier>* . <identifier>)
+;; | <identifier>
+;;
+;; The value returned by a `case-lambda' form is a procedure which
+;; matches the number of actual arguments against the signatures in
+;; the various clauses, in order. The first matching clause is
+;; selected, the corresponding values from the actual parameter list
+;; are bound to the variable names in the clauses and the body of the
+;; clause is evaluated.
+
+;;; Code:
+
+(define-module (srfi srfi-16)
+ #:re-export (case-lambda))
+
+;; Case-lambda is now provided by core psyntax.
HCoop / bpt / guile.git / blobdiff