Add new variable print-unreadable-function
* doc/lispref/streams.texi (Output Variables): Document it. * src/print.c (print_vectorlike): Use the variable. (syms_of_print): New variable print-unreadable-function (bug#52566).
This commit is contained in:
Lars Ingebrigtsen
parent
7e596463be
commit
e4d2a7894b
4 changed files with 308 additions and 220 deletions
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@ -872,6 +872,32 @@ If non-@code{nil}, this variable enables detection of circular and
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shared structure in printing. @xref{Circular Objects}.
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@end defvar
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@defvar print-unreadable-function
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By default, Emacs prints unreadable objects as @samp{#<...>"}. For
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instance:
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@example
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(prin1-to-string (make-marker))
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@result{} "#<marker in no buffer>"
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@end example
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If this variable is non-@code{nil}, it should be a function that will
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be called to handle printing of these objects. The first argument is
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the object, and the second argument is the @var{noescape} flag used by
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the printing functions (@pxref{Output Functions}).
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The function should return either @code{nil} (print nothing), or a
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string (which will be printed), or any other object (which means that
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the object should be printed normally). For instance:
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@example
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(let ((print-unreadable-function
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(lambda (object escape) "hello")))
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(prin1-to-string (make-marker)))
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@result{} "hello"
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@end example
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@end defvar
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@defvar print-gensym
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If non-@code{nil}, this variable enables detection of uninterned symbols
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(@pxref{Creating Symbols}) in printing. When this is enabled,
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8
etc/NEWS
8
etc/NEWS
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@ -977,12 +977,16 @@ functions.
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* Lisp Changes in Emacs 29.1
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--
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+++
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** New variable 'print-unreadable-function'.
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This variable allows changing how Emacs prints unreadable objects.
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---
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** The variable 'polling-period' now accepts floating point values.
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This means Emacs can now poll for input during Lisp execution more
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frequently than once in a second.
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--
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---
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** New function 'bidi-string-strip-control-characters'.
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This utility function is meant for displaying strings when it's
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essential that there's no bidirectional context.
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483
src/print.c
483
src/print.c
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@ -1387,6 +1387,7 @@ static bool
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print_vectorlike (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag,
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char *buf)
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{
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/* First do all the vectorlike types that have a readable syntax. */
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switch (PSEUDOVECTOR_TYPE (XVECTOR (obj)))
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{
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case PVEC_BIGNUM:
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@ -1398,77 +1399,7 @@ print_vectorlike (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag,
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strout (str, len, len, printcharfun);
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SAFE_FREE ();
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}
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break;
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case PVEC_MARKER:
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print_c_string ("#<marker ", printcharfun);
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/* Do you think this is necessary? */
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if (XMARKER (obj)->insertion_type != 0)
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print_c_string ("(moves after insertion) ", printcharfun);
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if (! XMARKER (obj)->buffer)
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print_c_string ("in no buffer", printcharfun);
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else
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{
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int len = sprintf (buf, "at %"pD"d in ", marker_position (obj));
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strout (buf, len, len, printcharfun);
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print_string (BVAR (XMARKER (obj)->buffer, name), printcharfun);
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}
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printchar ('>', printcharfun);
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break;
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case PVEC_OVERLAY:
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print_c_string ("#<overlay ", printcharfun);
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if (! XMARKER (OVERLAY_START (obj))->buffer)
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print_c_string ("in no buffer", printcharfun);
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else
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{
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int len = sprintf (buf, "from %"pD"d to %"pD"d in ",
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marker_position (OVERLAY_START (obj)),
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marker_position (OVERLAY_END (obj)));
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strout (buf, len, len, printcharfun);
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print_string (BVAR (XMARKER (OVERLAY_START (obj))->buffer, name),
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printcharfun);
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}
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printchar ('>', printcharfun);
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break;
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case PVEC_USER_PTR:
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{
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print_c_string ("#<user-ptr ", printcharfun);
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int i = sprintf (buf, "ptr=%p finalizer=%p",
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XUSER_PTR (obj)->p,
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XUSER_PTR (obj)->finalizer);
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strout (buf, i, i, printcharfun);
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printchar ('>', printcharfun);
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}
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break;
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case PVEC_FINALIZER:
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print_c_string ("#<finalizer", printcharfun);
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if (NILP (XFINALIZER (obj)->function))
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print_c_string (" used", printcharfun);
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printchar ('>', printcharfun);
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break;
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case PVEC_MISC_PTR:
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{
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/* This shouldn't happen in normal usage, but let's
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print it anyway for the benefit of the debugger. */
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int i = sprintf (buf, "#<ptr %p>", xmint_pointer (obj));
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strout (buf, i, i, printcharfun);
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}
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break;
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case PVEC_PROCESS:
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if (escapeflag)
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{
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print_c_string ("#<process ", printcharfun);
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print_string (XPROCESS (obj)->name, printcharfun);
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printchar ('>', printcharfun);
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}
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else
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print_string (XPROCESS (obj)->name, printcharfun);
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break;
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return true;
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case PVEC_BOOL_VECTOR:
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{
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@ -1513,70 +1444,7 @@ print_vectorlike (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag,
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print_c_string (" ...", printcharfun);
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printchar ('\"', printcharfun);
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}
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break;
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case PVEC_SUBR:
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print_c_string ("#<subr ", printcharfun);
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print_c_string (XSUBR (obj)->symbol_name, printcharfun);
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printchar ('>', printcharfun);
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break;
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case PVEC_XWIDGET:
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#ifdef HAVE_XWIDGETS
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{
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if (NILP (XXWIDGET (obj)->buffer))
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print_c_string ("#<killed xwidget>", printcharfun);
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else
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{
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#ifdef USE_GTK
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int len = sprintf (buf, "#<xwidget %u %p>",
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XXWIDGET (obj)->xwidget_id,
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XXWIDGET (obj)->widget_osr);
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#else
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int len = sprintf (buf, "#<xwidget %u %p>",
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XXWIDGET (obj)->xwidget_id,
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XXWIDGET (obj)->xwWidget);
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#endif
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strout (buf, len, len, printcharfun);
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}
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break;
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}
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#else
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emacs_abort ();
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#endif
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case PVEC_XWIDGET_VIEW:
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print_c_string ("#<xwidget view", printcharfun);
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printchar ('>', printcharfun);
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break;
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case PVEC_WINDOW:
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{
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int len = sprintf (buf, "#<window %"pI"d",
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XWINDOW (obj)->sequence_number);
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strout (buf, len, len, printcharfun);
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if (BUFFERP (XWINDOW (obj)->contents))
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{
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print_c_string (" on ", printcharfun);
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print_string (BVAR (XBUFFER (XWINDOW (obj)->contents), name),
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printcharfun);
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}
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printchar ('>', printcharfun);
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}
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break;
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case PVEC_TERMINAL:
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{
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struct terminal *t = XTERMINAL (obj);
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int len = sprintf (buf, "#<terminal %d", t->id);
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strout (buf, len, len, printcharfun);
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if (t->name)
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{
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print_c_string (" on ", printcharfun);
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print_c_string (t->name, printcharfun);
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}
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printchar ('>', printcharfun);
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}
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break;
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return true;
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case PVEC_HASH_TABLE:
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{
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@ -1649,6 +1517,253 @@ print_vectorlike (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag,
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print_c_string ("))", printcharfun);
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}
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return true;
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case PVEC_RECORD:
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{
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ptrdiff_t size = PVSIZE (obj);
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/* Don't print more elements than the specified maximum. */
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ptrdiff_t n
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= (FIXNATP (Vprint_length) && XFIXNAT (Vprint_length) < size
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? XFIXNAT (Vprint_length) : size);
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print_c_string ("#s(", printcharfun);
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for (ptrdiff_t i = 0; i < n; i ++)
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{
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if (i) printchar (' ', printcharfun);
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print_object (AREF (obj, i), printcharfun, escapeflag);
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}
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if (n < size)
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print_c_string (" ...", printcharfun);
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printchar (')', printcharfun);
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}
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return true;
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case PVEC_SUB_CHAR_TABLE:
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case PVEC_COMPILED:
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case PVEC_CHAR_TABLE:
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case PVEC_NORMAL_VECTOR:
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{
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ptrdiff_t size = ASIZE (obj);
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if (COMPILEDP (obj))
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{
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printchar ('#', printcharfun);
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size &= PSEUDOVECTOR_SIZE_MASK;
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}
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if (CHAR_TABLE_P (obj) || SUB_CHAR_TABLE_P (obj))
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{
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/* Print a char-table as if it were a vector,
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lumping the parent and default slots in with the
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character slots. But add #^ as a prefix. */
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/* Make each lowest sub_char_table start a new line.
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Otherwise we'll make a line extremely long, which
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results in slow redisplay. */
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if (SUB_CHAR_TABLE_P (obj)
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&& XSUB_CHAR_TABLE (obj)->depth == 3)
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printchar ('\n', printcharfun);
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print_c_string ("#^", printcharfun);
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if (SUB_CHAR_TABLE_P (obj))
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printchar ('^', printcharfun);
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size &= PSEUDOVECTOR_SIZE_MASK;
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}
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if (size & PSEUDOVECTOR_FLAG)
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return false;
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printchar ('[', printcharfun);
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int idx = SUB_CHAR_TABLE_P (obj) ? SUB_CHAR_TABLE_OFFSET : 0;
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Lisp_Object tem;
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ptrdiff_t real_size = size;
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/* For a sub char-table, print heading non-Lisp data first. */
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if (SUB_CHAR_TABLE_P (obj))
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{
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int i = sprintf (buf, "%d %d", XSUB_CHAR_TABLE (obj)->depth,
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XSUB_CHAR_TABLE (obj)->min_char);
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strout (buf, i, i, printcharfun);
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}
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/* Don't print more elements than the specified maximum. */
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if (FIXNATP (Vprint_length)
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&& XFIXNAT (Vprint_length) < size)
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size = XFIXNAT (Vprint_length);
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for (int i = idx; i < size; i++)
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{
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if (i) printchar (' ', printcharfun);
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tem = AREF (obj, i);
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print_object (tem, printcharfun, escapeflag);
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}
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if (size < real_size)
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print_c_string (" ...", printcharfun);
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printchar (']', printcharfun);
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}
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return true;
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default:
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break;
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}
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/* Then do all the pseudovector types that don't have a readable
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syntax. First check whether this is handled by
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`print-unreadable-function'. */
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if (!NILP (Vprint_unreadable_function)
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&& FUNCTIONP (Vprint_unreadable_function))
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{
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ptrdiff_t count = SPECPDL_INDEX ();
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/* Bind `print-unreadable-function' to nil to avoid accidental
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infinite recursion in the function called. */
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Lisp_Object func = Vprint_unreadable_function;
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specbind (Qprint_unreadable_function, Qnil);
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Lisp_Object result = CALLN (Ffuncall, func, obj,
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escapeflag? Qt: Qnil);
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unbind_to (count, Qnil);
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if (!NILP (result))
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{
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if (STRINGP (result))
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print_string (result, printcharfun);
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/* It's handled, so stop processing here. */
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return true;
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}
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}
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/* Not handled; print unreadable object. */
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switch (PSEUDOVECTOR_TYPE (XVECTOR (obj)))
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{
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case PVEC_MARKER:
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print_c_string ("#<marker ", printcharfun);
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/* Do you think this is necessary? */
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if (XMARKER (obj)->insertion_type != 0)
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print_c_string ("(moves after insertion) ", printcharfun);
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if (! XMARKER (obj)->buffer)
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print_c_string ("in no buffer", printcharfun);
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else
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{
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int len = sprintf (buf, "at %"pD"d in ", marker_position (obj));
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strout (buf, len, len, printcharfun);
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print_string (BVAR (XMARKER (obj)->buffer, name), printcharfun);
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}
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printchar ('>', printcharfun);
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break;
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case PVEC_OVERLAY:
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print_c_string ("#<overlay ", printcharfun);
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if (! XMARKER (OVERLAY_START (obj))->buffer)
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print_c_string ("in no buffer", printcharfun);
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else
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{
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int len = sprintf (buf, "from %"pD"d to %"pD"d in ",
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marker_position (OVERLAY_START (obj)),
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marker_position (OVERLAY_END (obj)));
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strout (buf, len, len, printcharfun);
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print_string (BVAR (XMARKER (OVERLAY_START (obj))->buffer, name),
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printcharfun);
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}
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printchar ('>', printcharfun);
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break;
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case PVEC_USER_PTR:
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{
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print_c_string ("#<user-ptr ", printcharfun);
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int i = sprintf (buf, "ptr=%p finalizer=%p",
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XUSER_PTR (obj)->p,
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XUSER_PTR (obj)->finalizer);
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strout (buf, i, i, printcharfun);
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printchar ('>', printcharfun);
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}
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break;
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case PVEC_FINALIZER:
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print_c_string ("#<finalizer", printcharfun);
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if (NILP (XFINALIZER (obj)->function))
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print_c_string (" used", printcharfun);
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printchar ('>', printcharfun);
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break;
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case PVEC_MISC_PTR:
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{
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/* This shouldn't happen in normal usage, but let's
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print it anyway for the benefit of the debugger. */
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int i = sprintf (buf, "#<ptr %p>", xmint_pointer (obj));
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strout (buf, i, i, printcharfun);
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}
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break;
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case PVEC_PROCESS:
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if (escapeflag)
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{
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print_c_string ("#<process ", printcharfun);
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print_string (XPROCESS (obj)->name, printcharfun);
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printchar ('>', printcharfun);
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}
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else
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print_string (XPROCESS (obj)->name, printcharfun);
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break;
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case PVEC_SUBR:
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print_c_string ("#<subr ", printcharfun);
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print_c_string (XSUBR (obj)->symbol_name, printcharfun);
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printchar ('>', printcharfun);
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break;
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case PVEC_XWIDGET:
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#ifdef HAVE_XWIDGETS
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{
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if (NILP (XXWIDGET (obj)->buffer))
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print_c_string ("#<killed xwidget>", printcharfun);
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else
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{
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#ifdef USE_GTK
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int len = sprintf (buf, "#<xwidget %u %p>",
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XXWIDGET (obj)->xwidget_id,
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XXWIDGET (obj)->widget_osr);
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#else
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int len = sprintf (buf, "#<xwidget %u %p>",
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XXWIDGET (obj)->xwidget_id,
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XXWIDGET (obj)->xwWidget);
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#endif
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strout (buf, len, len, printcharfun);
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}
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break;
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}
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#else
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emacs_abort ();
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#endif
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case PVEC_XWIDGET_VIEW:
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print_c_string ("#<xwidget view", printcharfun);
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printchar ('>', printcharfun);
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break;
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case PVEC_WINDOW:
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{
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int len = sprintf (buf, "#<window %"pI"d",
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XWINDOW (obj)->sequence_number);
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strout (buf, len, len, printcharfun);
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if (BUFFERP (XWINDOW (obj)->contents))
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{
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print_c_string (" on ", printcharfun);
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print_string (BVAR (XBUFFER (XWINDOW (obj)->contents), name),
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printcharfun);
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}
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printchar ('>', printcharfun);
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}
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break;
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case PVEC_TERMINAL:
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{
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struct terminal *t = XTERMINAL (obj);
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int len = sprintf (buf, "#<terminal %d", t->id);
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strout (buf, len, len, printcharfun);
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if (t->name)
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{
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print_c_string (" on ", printcharfun);
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print_c_string (t->name, printcharfun);
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}
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printchar ('>', printcharfun);
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}
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break;
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case PVEC_BUFFER:
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@ -1756,89 +1871,6 @@ print_vectorlike (Lisp_Object obj, Lisp_Object printcharfun, bool escapeflag,
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printchar ('>', printcharfun);
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break;
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case PVEC_RECORD:
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{
|
||||
ptrdiff_t size = PVSIZE (obj);
|
||||
|
||||
/* Don't print more elements than the specified maximum. */
|
||||
ptrdiff_t n
|
||||
= (FIXNATP (Vprint_length) && XFIXNAT (Vprint_length) < size
|
||||
? XFIXNAT (Vprint_length) : size);
|
||||
|
||||
print_c_string ("#s(", printcharfun);
|
||||
for (ptrdiff_t i = 0; i < n; i ++)
|
||||
{
|
||||
if (i) printchar (' ', printcharfun);
|
||||
print_object (AREF (obj, i), printcharfun, escapeflag);
|
||||
}
|
||||
if (n < size)
|
||||
print_c_string (" ...", printcharfun);
|
||||
printchar (')', printcharfun);
|
||||
}
|
||||
break;
|
||||
|
||||
case PVEC_SUB_CHAR_TABLE:
|
||||
case PVEC_COMPILED:
|
||||
case PVEC_CHAR_TABLE:
|
||||
case PVEC_NORMAL_VECTOR:
|
||||
{
|
||||
ptrdiff_t size = ASIZE (obj);
|
||||
if (COMPILEDP (obj))
|
||||
{
|
||||
printchar ('#', printcharfun);
|
||||
size &= PSEUDOVECTOR_SIZE_MASK;
|
||||
}
|
||||
if (CHAR_TABLE_P (obj) || SUB_CHAR_TABLE_P (obj))
|
||||
{
|
||||
/* Print a char-table as if it were a vector,
|
||||
lumping the parent and default slots in with the
|
||||
character slots. But add #^ as a prefix. */
|
||||
|
||||
/* Make each lowest sub_char_table start a new line.
|
||||
Otherwise we'll make a line extremely long, which
|
||||
results in slow redisplay. */
|
||||
if (SUB_CHAR_TABLE_P (obj)
|
||||
&& XSUB_CHAR_TABLE (obj)->depth == 3)
|
||||
printchar ('\n', printcharfun);
|
||||
print_c_string ("#^", printcharfun);
|
||||
if (SUB_CHAR_TABLE_P (obj))
|
||||
printchar ('^', printcharfun);
|
||||
size &= PSEUDOVECTOR_SIZE_MASK;
|
||||
}
|
||||
if (size & PSEUDOVECTOR_FLAG)
|
||||
return false;
|
||||
|
||||
printchar ('[', printcharfun);
|
||||
|
||||
int idx = SUB_CHAR_TABLE_P (obj) ? SUB_CHAR_TABLE_OFFSET : 0;
|
||||
Lisp_Object tem;
|
||||
ptrdiff_t real_size = size;
|
||||
|
||||
/* For a sub char-table, print heading non-Lisp data first. */
|
||||
if (SUB_CHAR_TABLE_P (obj))
|
||||
{
|
||||
int i = sprintf (buf, "%d %d", XSUB_CHAR_TABLE (obj)->depth,
|
||||
XSUB_CHAR_TABLE (obj)->min_char);
|
||||
strout (buf, i, i, printcharfun);
|
||||
}
|
||||
|
||||
/* Don't print more elements than the specified maximum. */
|
||||
if (FIXNATP (Vprint_length)
|
||||
&& XFIXNAT (Vprint_length) < size)
|
||||
size = XFIXNAT (Vprint_length);
|
||||
|
||||
for (int i = idx; i < size; i++)
|
||||
{
|
||||
if (i) printchar (' ', printcharfun);
|
||||
tem = AREF (obj, i);
|
||||
print_object (tem, printcharfun, escapeflag);
|
||||
}
|
||||
if (size < real_size)
|
||||
print_c_string (" ...", printcharfun);
|
||||
printchar (']', printcharfun);
|
||||
}
|
||||
break;
|
||||
|
||||
#ifdef HAVE_MODULES
|
||||
case PVEC_MODULE_FUNCTION:
|
||||
{
|
||||
|
|
@ -2464,4 +2496,19 @@ priorities. Values other than nil or t are also treated as
|
|||
|
||||
print_prune_charset_plist = Qnil;
|
||||
staticpro (&print_prune_charset_plist);
|
||||
|
||||
DEFVAR_LISP ("print-unreadable-function", Vprint_unreadable_function,
|
||||
doc: /* Function called when printing unreadable objects.
|
||||
By default, Emacs printing functions (like `prin1') print unreadable
|
||||
objects like \"#<...>\", where \"...\" describes the object (for
|
||||
instance, \"#<marker in no buffer>\"). If this variable is non-nil,
|
||||
it should be a function which will be called to print the object instead.
|
||||
|
||||
It will be called with two arguments: The object to be printed, and
|
||||
noescape (see `prin1-to-string'). If this function returns nil, the
|
||||
object will be printed as normal. If it returns a string, that string
|
||||
will then be printed. If the function returns anything else, the
|
||||
object will not be printed. */);
|
||||
Vprint_unreadable_function = Qnil;
|
||||
DEFSYM (Qprint_unreadable_function, "print-unreadable-function");
|
||||
}
|
||||
|
|
|
|||
|
|
@ -406,5 +406,16 @@ otherwise, use a different charset."
|
|||
(should (equal printed-nonprints
|
||||
"(55296 57343 778 65535 8194 8204)"))))
|
||||
|
||||
(ert-deftest test-unreadable ()
|
||||
(should (equal (prin1-to-string (make-marker)) "#<marker in no buffer>"))
|
||||
(let ((print-unreadable-function
|
||||
(lambda (_object _escape)
|
||||
"hello")))
|
||||
(should (equal (prin1-to-string (make-marker)) "hello")))
|
||||
(let ((print-unreadable-function
|
||||
(lambda (_object _escape)
|
||||
t)))
|
||||
(should (equal (prin1-to-string (make-marker)) ""))))
|
||||
|
||||
(provide 'print-tests)
|
||||
;;; print-tests.el ends here
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue