;;;; Utilities used by HAMT

;;; Copyright MMIV-MMXVII Arthur A. Gleckler.  All rights reserved.

;; Permission is hereby granted, free of charge, to any person
;; obtaining a copy of this software and associated documentation
;; files (the "Software"), to deal in the Software without
;; restriction, including without limitation the rights to use, copy,
;; modify, merge, publish, distribute, sublicense, and/or sell copies
;; of the Software, and to permit persons to whom the Software is
;; furnished to do so, subject to the following conditions:

;; The above copyright notice and this permission notice shall be
;; included in all copies or substantial portions of the Software.

;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
;; NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
;; HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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;; DEALINGS IN THE SOFTWARE.

(define-syntax assert
  (syntax-rules ()
    ((_ (operator argument ...))
     (unless (operator argument ...)
       (error "Assertion failed:"
	      '(operator argument ...)
	      (list 'operator argument ...))))
    ((_ expression)
     (unless expression
       (error "Assertion failed:" 'expression)))))

(define-syntax do-list
  (syntax-rules ()
    ((_ (variable list) body ...)
     (do ((remaining list (cdr remaining)))
	 ((null? remaining))
       (let ((variable (car remaining)))
	 body ...)))
    ((_ (element-variable index-variable list) body ...)
     (do ((remaining list (cdr remaining))
	  (index-variable 0 (+ index-variable 1)))
	 ((null? remaining))
       (let ((element-variable (car remaining)))
	 body ...)))))

(define string-comparator
  (make-comparator string? string=? #f string-hash))

(define (make-string-hash-table)
  (make-hash-table string-comparator))

(define (with-output-to-string thunk)
  (parameterize ((current-output-port (open-output-string)))
    (thunk)
    (get-output-string (current-output-port))))