)show and evalDomainOpPred

[Waldek Hebisch]

I think that )show should use the same routine as HyperDoc to
produce list of signatures. Qian wrote that evalDomainOpPred
is more reliable than simpHasPred since evalDomainOpPred tries
to use values of predicates stored in domain vector. But due
to optimizations predicates in database are different than
predicates stored in domain vector. The recent trouble
with AssociatedLieAlgebra is an example: evalDomainOpPred
for long time missed most of the signatures.

IMO printing more signatures is less problematic than
missing signatures. In principle using simpHasPred we
can warn users: currently HyperDoc shows all signature
such that condition does not simplify to false. But
when the result of simplification is different from true
we could print the simplified condition or a message that
condition can not be fully simplified.

BTW: Ideally this filtering should be moved to Spad and
merged with API code, but as first step I would like to
have less routines in Boot.

--
Waldek Hebisch