;;;; This file contains things for the extensions package which can't
;;;; be built at cross-compile time, and perhaps also some things
;;;; which might as well not be built at cross-compile time because
;;;; they're not needed then. Things which can't be built at
;;;; cross-compile time (e.g. because they need machinery which only
;;;; exists inside SBCL's implementation of the LISP package) do not
;;;; belong in this file.

;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.

(in-package "SB!IMPL")

;;;; miscellaneous I/O

;;; INDENTING-FURTHER is a user-level macro which may be used to locally
;;; increment the indentation of a stream.
(defmacro indenting-further (stream more &rest body)
  #!+sb-doc
  "Causes the output of the indenting Stream to indent More spaces. More is
  evaluated twice."
  `(unwind-protect
     (progn
      (incf (sb!impl::indenting-stream-indentation ,stream) ,more)
      ,@body)
     (decf (sb!impl::indenting-stream-indentation ,stream) ,more)))

(defun skip-whitespace (&optional (stream *standard-input*))
  (loop (let ((char (read-char stream)))
	  (unless (sb!impl::whitespacep char)
	    (return (unread-char char stream))))))

(defun listen-skip-whitespace (&optional (stream *standard-input*))
  #!+sb-doc
  "See LISTEN. Any whitespace in the input stream will be flushed."
  (do ((char (read-char-no-hang stream nil nil nil)
	     (read-char-no-hang stream nil nil nil)))
      ((null char) nil)
    (cond ((not (sb!impl::whitespace-char-p char))
	   (unread-char char stream)
	   (return t)))))