Commit 3a3aa0e0 authored by Karl Fogel's avatar Karl Fogel
Browse files

Move interactive `transpose-regions' to Lisp

Define `transpose-regions' in Lisp, because its complex interactive
spec was ungainly in C, and change the C version to non-interactive
`transpose-regions-internal'.  The Lisp function is just a wrapper
around the C function, which still does all the work.

* lisp/simple.el (transpose-regions): New wrapper function, with
  interactive spec taken from old C `transpose-regions'.

* src/editfns.c (Ftranspose_regions): Rename to...
  (Ftranspose_regions_internal): ...here, and remove interactive spec.

Discussion on Emacs Devel:

  From: Karl Fogel
  To: Emacs Development
  Cc: Richard Copley, Charles A. Roelli
  Subject: Re: [Emacs-diffs] master b88e7c8b: \
           Make transpose-regions interactive (Bug#30343)
  Date: Fri, 16 Mar 2018 10:23:31 -0500
  Message-ID: <87po44jb7w.fsf@red-bean.com>

  https://lists.gnu.org/archive/html/emacs-devel/2018-03/msg00555.html
parent 9667ba25
......@@ -7014,6 +7014,34 @@ With argument 0, interchanges line point is in with line mark is in."
(forward-line arg))))
arg))
(defun transpose-regions (startr1 endr1 startr2 endr2 &optional leave-markers)
"Transpose region STARTR1 to ENDR1 with STARTR2 to ENDR2.
The regions should not be overlapping, because the size of the buffer is
never changed in a transposition.
Optional fifth arg LEAVE-MARKERS, if non-nil, means don't update
any markers that happen to be located in the regions.
Transposing beyond buffer boundaries is an error.
Interactively, STARTR1 and ENDR1 are point and mark; STARTR2 and ENDR2
are the last two marks pushed to the mark ring; LEAVE-MARKERS is nil.
If a prefix argument N is given, STARTR2 and ENDR2 are the two
successive marks N entries back in the mark ring. A negative prefix
argument instead counts forward from the oldest mark in the mark
ring."
(interactive
(if (< (length mark-ring) 2)
(error "Other region must be marked before transposing two regions")
(let* ((num (if current-prefix-arg
(prefix-numeric-value current-prefix-arg)
0))
(ring-length (length mark-ring))
(eltnum (mod num ring-length))
(eltnum2 (mod (1+ num) ring-length)))
(list (point) (mark) (elt mark-ring eltnum) (elt mark-ring eltnum2)))))
(transpose-regions-internal startr1 endr1 startr2 endr2 leave-markers))
;; FIXME seems to leave point BEFORE the current object when ARG = 0,
;; which seems inconsistent with the ARG /= 0 case.
;; FIXME document SPECIAL.
......
......@@ -5112,16 +5112,7 @@ transpose_markers (ptrdiff_t start1, ptrdiff_t end1,
}
}
DEFUN ("transpose-regions", Ftranspose_regions, Stranspose_regions, 4, 5,
"(if (< (length mark-ring) 2)\
(error \"Other region must be marked before transposing two regions\")\
(let* ((num (if current-prefix-arg\
(prefix-numeric-value current-prefix-arg)\
0))\
(ring-length (length mark-ring))\
(eltnum (mod num ring-length))\
(eltnum2 (mod (1+ num) ring-length)))\
(list (point) (mark) (elt mark-ring eltnum) (elt mark-ring eltnum2))))",
DEFUN ("transpose-regions-internal", Ftranspose_regions_internal, Stranspose_regions_internal, 4, 5, 0,
doc: /* Transpose region STARTR1 to ENDR1 with STARTR2 to ENDR2.
The regions should not be overlapping, because the size of the buffer is
never changed in a transposition.
......@@ -5129,14 +5120,7 @@ never changed in a transposition.
Optional fifth arg LEAVE-MARKERS, if non-nil, means don't update
any markers that happen to be located in the regions.
Transposing beyond buffer boundaries is an error.
Interactively, STARTR1 and ENDR1 are point and mark; STARTR2 and ENDR2
are the last two marks pushed to the mark ring; LEAVE-MARKERS is nil.
If a prefix argument N is given, STARTR2 and ENDR2 are the two
successive marks N entries back in the mark ring. A negative prefix
argument instead counts forward from the oldest mark in the mark
ring. */)
Transposing beyond buffer boundaries is an error. */)
(Lisp_Object startr1, Lisp_Object endr1, Lisp_Object startr2, Lisp_Object endr2, Lisp_Object leave_markers)
{
register ptrdiff_t start1, end1, start2, end2;
......@@ -5581,5 +5565,5 @@ functions if all the text being accessed has this property. */);
defsubr (&Swiden);
defsubr (&Snarrow_to_region);
defsubr (&Ssave_restriction);
defsubr (&Stranspose_regions);
defsubr (&Stranspose_regions_internal);
}
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