Dear Maude Abusers,

A new alpha release can be accessed at SRI-CSL in:

~eker/public_html/Maude/Alpha89i/

or downloaded from:

http://www.csl.sri.com/~eker/Maude/Alpha89i/

Alpha release site authentication:

User Name: maudeabuser
Password: bughunter

Bug fixes
----------
(1) Two bugs that caused narrowing data structures not to be deleted
when the module they were working on was deleted. Because various
narrowing structure hold root pointer this caused the garbage
collector to try and trace dag node whose symbols no longer existed
with major memory corruption. Provoked by an example from Daniel
Elenius <elenius@csl.sri.com>.

(2) Bug where multiple calls to a cached descent function such as
metaUnify() with identical arguments cause the function to be
re-evaluated from scratch. This evaluation from scratch sill happens
for the index 0 solution (otherwise we would search the cache for the
first solution) and the failure index (because the state information
is deleted on failure). Slowness provoked by examples from Santiago
Escobar <sescobar@dsic.upv.es> and Ralf Sasse <rsasse@cs.uiuc.edu>.

Change
-------
Narrowing is reflected by a second descent function:
 op metaNarrow : Module Term Qid Bound Nat ~> ResultPair? [...] .
Here there is no pattern, so no matching takes place and each state
that satisfies the other criteria (search type, depth) is returned
once. Also when the state is turned into a metaterm, the variables are
renamed so that no variable occurs in more than one returned state.
This functionality was requested by Daniel Elenius.

Steven