[cduce-users] default match policy not working in sequences
Alain.Frisch at inria.fr
Thu Nov 4 01:47:36 CET 2004
Giuseppe Castagna wrote:
>> - reuse predefined types:
>> [ <a>_ /A | <b>_ /B ] (where A and B are already defined)
> I do not see any advantage here. This is equivalent to
> [ <a>_ A | <b>_ B ]
No, actually, it is equivalent to [ <a>_ | <b>_ ] (if A and B contain
the empty sequence). Sorry, I really meant something like:
[ (<a>_ /A | <b>_ /B) R ]
where R is a complex regexp.
> Yes this is an advantage. In any case I believe that / is not a good
> syntax. Too close to difference, and field removal, and possible
> confusion with projections. I know that we are running out of symbols
> but we should pick a different one.
I did not invent the / notation; I took it from lex (the lexer
generator), where it expresses a constraint on the trailing context.
Any other suggestion for the syntax ?
>> 3. it is the notation I use in my PhD manuscript (p 176 of
>> the version you have)
> Come-on, every reader will have commited suicide before arriving at page
> 176 (you may wonder why I am still alive) :-)
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