From 4b4ef6dfcf12e1db846b26a3b812aa010360d62f Mon Sep 17 00:00:00 2001 From: Kaz Kylheku Date: Mon, 31 Oct 2016 06:49:22 -0700 Subject: Relax restrictions on dwim places. No longer require the leftmost expression in a dwim place to itself be a place, except when the expression evaluates to a list, and the list is subject to an element deletion or a range operation. * eval.c (eval_init): Register dwim-set and dwim-del with one additional argument that the C functions now take. * lib.c (dwim_set, dwim_del): Take a new place_p argument which informs these functions whether the object they are operating on came from a syntactic place. The forbidden situations are diagnosed based on this flag: modification of the subrange of a list, or deletion of a list ref. Some error messages reworded. * lib.h (dwim_set, dwim_del): Declarations updated. * share/txr/stdlib/place.tl (defplace dwim): Produce a different update, clobber and delete expansion when the obj-place form isn't a place. In the non-place case, do not assign the result of the sys:dwim-set or sys:dwim-del operation back obj-place. Furthermore, pass a Boolean flag to sys:dwim-set and sys:dwim-del indicating which situation is the case: did the object argument come from a place or non-place. * txr.1: Documentation updated. --- lib.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'lib.h') diff --git a/lib.h b/lib.h index 8bc72fd4..50ee8640 100644 --- a/lib.h +++ b/lib.h @@ -962,8 +962,8 @@ val empty(val seq); val sub(val seq, val from, val to); val ref(val seq, val ind); val refset(val seq, val ind, val newval); -val dwim_set(val seq, varg); -val dwim_del(val seq, val ind_range); +val dwim_set(val place_p, val seq, varg); +val dwim_del(val place_p, val seq, val ind_range); val butlast(val seq, val idx); val replace(val seq, val items, val from, val to); val update(val seq, val fun); -- cgit v1.2.3