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| author | Kaz Kylheku <kaz@kylheku.com> | 2019-04-05 15:22:37 -0700 |
|---|---|---|
| committer | Kaz Kylheku <kaz@kylheku.com> | 2019-04-05 15:22:37 -0700 |
| commit | 5ca3693a7b5d65fd5aa67c737e7a60b457db2281 (patch) | |
| tree | 83c85bce2661b588a0445619fc58f121359c4468 /share | |
| parent | 06ce08dc2c0d2db522c5f6293cf9a28c2c22d24a (diff) | |
| download | txr-5ca3693a7b5d65fd5aa67c737e7a60b457db2281.tar.gz txr-5ca3693a7b5d65fd5aa67c737e7a60b457db2281.tar.bz2 txr-5ca3693a7b5d65fd5aa67c737e7a60b457db2281.zip | |
compiler: better shared test for sys:switch.
* share/txr/stdlib/compiler.tl (compiler comp-switch): The
shared test here is both inaccurate and O(n^2). It tests that
all the remaining branches of the code are tails of the first
branch. However, this is not strict enough: we need to also
test that the tails are in their order of appearance. We can
do that in O(n) time.
Diffstat (limited to 'share')
| -rw-r--r-- | share/txr/stdlib/compiler.tl | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/share/txr/stdlib/compiler.tl b/share/txr/stdlib/compiler.tl index cbd2b6ee..3d906866 100644 --- a/share/txr/stdlib/compiler.tl +++ b/share/txr/stdlib/compiler.tl @@ -524,7 +524,12 @@ (mac-param-bind form (op idx-form cases-vec) form (let* ((ncases (len cases-vec)) (cs (and (plusp ncases) (conses [cases-vec 0]))) - (shared (and cs (all [cases-vec 1..:] (op memq @1 cs)))) + (shared (and cs + (let ((c cs) + (d (cdr (list-vec cases-vec)))) + (whilet ((m (if d (memq (pop d) c)))) + (set c m)) + (null d)))) (cases (if shared (let ((cs-nil ^(,*cs nil))) [mapcar ldiff cs-nil (cdr cs-nil)]) |