[m-dev.] feature request -- empty/1 pred in string library

Douglas Auclair dauclair at msn.com
Wed Mar 26 06:21:20 AEDT 2003

Dear all,

I was doing some programming with strings and was surprised to find that the 
string library does not have an empty/1 semideterministic predicate.  This 
would be especially useful in higher-order programming:

Content = filter(isnt(empty), ListOfStrings).

I know an equivalent predicate can be easily constructed:

Empty = (pred(String::in) is semidet :- length(String) = 0),
Content = filter(isnt(Empty), ListOfStrings).

but could the predicate be added to string library, even so?

Doug Auclair

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