;; guile-lib
;; Copyright (C) 2004 Andy Wingo <wingo at pobox dot com>

;; This program is free software; you can redistribute it and/or    
;; modify it under the terms of the GNU General Public License as   
;; published by the Free Software Foundation; either version 2 of   
;; the License, or (at your option) any later version.              
;;                                                                  
;; This program 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 General Public License for more details.                     
;;                                                                  
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, contact:
;;
;; Free Software Foundation           Voice:  +1-617-542-5942
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;; Boston, MA  02111-1307,  USA       gnu@gnu.org

;;; Commentary:
;;
;;@c it's really texinfo
;; Defines a macro to time execution of a body of expressions. Each
;; element is timed individually.
;;
;;; Code:

(define-module (debugging time)
  #:use-module (scheme documentation)
  #:export (time))

(define-macro-with-docs (time expr . others)
  "syntax: @code{(time @var{expr1} @var{expr2}...)}

Times the execution of a list of expressions, in milliseconds. The
resolution is limited to guile's @code{internal-time-units-per-second}.
Disregards the expressions' return value(s) (FIXME)."
  (let ((x (gensym)))
    `(let ((,x (get-internal-run-time)))
       ,expr
       (format #t "~A ms\n" (* 1000 (/ (- (get-internal-run-time) ,x)
                                       internal-time-units-per-second)))
       ,@(if (null? others) '() `((time ,@others))))))

;;; arch-tag: ff9cb210-9d1b-4ad4-aa5d-27a23edc91f2