Gabriel Dos Reis wrote:
> On Sat, 19 May 2007, Martin Rubey wrote:
> | Are you saying:
> |
> | if A and B or C then ...
> |
> | should be, but currently isn't allowed in the context of conditional
> exports?
> | (I think it is allowed already now.)
>
> I'm saying that we seriously consider the above when A, B or C
> happen to be patterns (`is form') or attribute queries (`has form').
> Note that from Spad point of view, they are just predicates.
>
>From aggcat.spad.pamphlet:
if Entry has SetCategory and % has finiteAggregate then
entry?: (Entry,%) -> Boolean
++ entry?(x,u) tests if x equals \axiom{u . i} for some index i.
Form aggcat2.spad.pamphlet:
if B has ListAggregate(R) or not(B has shallowlyMutable) then
-- A is a list-oid, and B is either list-oids or not mutable
map(f, l) == construct [f s for s in entries l]
So, as Martin wrote simple boolean operators already work. I belive
that there are restrictions, namely that more complicated expressions
do not work. I agree that also complicated expressions should be
allowed, but support (or lack of it) does not cause conceptual or
practical difficulties: complicated expressions are just syntatic
sugar for combinations of simple expressions.
--
Waldek Hebisch
[EMAIL PROTECTED]
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