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Diffstat (limited to 'module/srfi/srfi-31.scm')
-rw-r--r-- | module/srfi/srfi-31.scm | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/module/srfi/srfi-31.scm b/module/srfi/srfi-31.scm new file mode 100644 index 000000000..f11aa8419 --- /dev/null +++ b/module/srfi/srfi-31.scm @@ -0,0 +1,35 @@ +;;; srfi-31.scm --- special form for recursive evaluation + +;; Copyright (C) 2004, 2006, 2012 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 + +;;; Original author: Rob Browning <rlb@defaultvalue.org> + +(define-module (srfi srfi-31) + #:export (rec)) + +(cond-expand-provide (current-module) '(srfi-31)) + +(define-syntax rec + (syntax-rules () + "Return the given object, defined in a lexical environment where +NAME is bound to itself." + ((_ (name . formals) body ...) ; procedure + (letrec ((name (lambda formals body ...))) + name)) + ((_ name expr) ; arbitrary object + (letrec ((name expr)) + name)))) |