;;; Time-stamp: <06/05/31 21:23:22 noel>
;;; Copyright (C) by Noel Welsh.

;;; 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., 59 Temple
;;; Place, Suite 330, Boston, MA 02111-1307 USA

;;; Author: Noel Welsh <>
;; Commentary:
(module base mzscheme

  (provide (all-defined))
  (define-struct (exn:idcheck exn) ())

  (define-syntax raise-exn:idcheck
    (syntax-rules ()
      ((raise-exn-idcheck msg)
         (string->immutable-string msg)

  ;; --- Copied from Unlib ---
  ;; assoc-value/default : any1 (list-of (cons any1 any2)) any2 -> any2
  ;; Searches for a value by key in a list of key/value pairs
  ;; (an association list). If the key is not found, the default
  ;; value is returned instead.
  (define (assoc-value/default key alist default)
    (let ([kvp (assoc key alist)])
      (if kvp
          (cdr kvp)