match: remove bad restriction from @(sme) and @(end).

The end pattern in @(sme) and @(end) does not have to be a
list pattern, dotted or otherwise. It should support any
pattern whatsoever for a single object, which should match the
terminating atom. The documentation says that, though not very
clearly; it is reworded also.

* stdlib/match.tl (check-end): Remove this function, since
the end pattern can be any pattern.
(pat-len): Bugfix: we are using the meq function incorrectly.
The object being compared against several alternatives
must be the leftmost argument of meq. This bug prevents a
pattern like @(evenp @x) to be correctly considered of
length zero.
(sme, end): Remove calls to check-end, and just refer to
original end variable.

* tests/011/patmatch.tl: New tests.

* txr.1: clarify that the end pattern may be any pattern,
which can match just the terminating atom or a possibly
dotted suffix.

1 files changed, 10 insertions, 0 deletions

diff --git a/tests/011/patmatch.tl b/tests/011/patmatch.tl
index bb67e32e..6d071f3d 100644
--- a/tests/011/patmatch.tl
+++ b/tests/011/patmatch.tl
@@ -602,6 +602,16 @@
   (match @gs 0 gs) :error
   (match @gs :gs gs) :gs)
 
+(mtest
+  (match @(end @x) '(1 . 2) x) 2
+  (match @(end @(evenp @x)) '(1 . 2) x) 2
+  (match @(end (@z . @x)) '(1 . 2) (list z x)) (1 2)
+  (match @(end (@z . @(evenp @x))) '(1 . 2) (list z x)) (1 2))
+
+(mtest
+  (match @(sme (@a) (@b) @x) '(0 1 . 2) (list a b x)) (0 1 2)
+  (match @(sme (@a) (@b) @(evenp @x)) '(0 1 . 2) (list a b x)) (0 1 2))
+
 (compile-only
   (eval-only
     (with-compile-opts (nil unused)