andrew at erlenstar.demon.co.uk
Wed Mar 7 11:20:54 PST 2001
>>>>> "Clive" == Clive D W Feather <clive at demon.net> writes:
Clive> wildmat = wildmat-pattern *("," ["!"] wildmat-pattern)
I reiterate my objection that a single wildmat, and a comma-delimited
list of (possibly negated) wildmats, are separate syntactic entities
and should not be combined in this way.
The combined approach disguises the fact that we are making
incompatible changes to commands such as LIST ACTIVE, and has no
justification either from a specification or implementation point of
view. In fact, the present text severely interferes with attempts to
handle complex pattern lists efficiently.
Clive> [W6: the grammar does not treat , in sets as special. This
Clive> means that the wildmat "a[b,c]d" is a single pattern that
Clive> matches the three strings "abd", "a,d", and "acd". Are we
Clive> happy with this ? It matches existing practice
it does no such thing. Existing practice, where a list of wildmats is
expected, treats ',' as a delimiter without any escape mechanism (and
none is needed).
Clive> but means that you can't split a wildmat into the component
Clive> patterns just by looking for unescaped commas.
which is intolerable.
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