Function: read

read is a function defined in lread.c.

Signature

(read &optional STREAM)

Documentation

Read one Lisp expression as text from STREAM, return as Lisp object.

If STREAM is nil, use the value of standard-input (which see). STREAM or the value of standard-input may be:
 a buffer (read from point and advance it)
 a marker (read from where it points and advance it)
 a function (call it with no arguments for each character,
     call it with a char as argument to push a char back)
 a string (takes text from string, starting at the beginning)
 t (read text line using minibuffer and use it, or read from
    standard input in batch mode).

Probably introduced at or before Emacs version 1.1.

Aliases

edebug-read-string edebug-read-symbol

Source Code

// Defined in /usr/src/emacs/src/lread.c
{
  if (NILP (stream))
    stream = Vstandard_input;
  if (EQ (stream, Qt))
    stream = Qread_char;
  if (EQ (stream, Qread_char))
    /* FIXME: ?! This is used when the reader is called from the
       minibuffer without a stream, as in (read).  But is this feature
       ever used, and if so, why?  IOW, will anything break if this
       feature is removed !?  */
    return call1 (intern ("read-minibuffer"),
		  build_string ("Lisp expression: "));

  return read_internal_start (stream, Qnil, Qnil);
}