Re: Ann: SWI-Prolog 7.1.0
Alan Baljeu <[email protected]>
| Newsgroups | gmane.comp.ai.prolog.swi |
|---|---|
| Message-ID | <[email protected]> |
>> - Unquoted atoms may contain internal dots. E.g., a.b is an >> atom. >> >> I find this confusing given V.b is emphatically not an atom. >> What's the motivation? > >Basically convenience when handling identifiers for languages that >can do this. It is controlled by a flag. So far, it seems to >cause so little confusion that I have decided to make the default >to accept it. If it proves problematic we can backtrack. Note that >you don't have to use :-). Following Paulo's advice, quoted write >emits 'a.b'. A while ago I considered using a.b as a shortcut meaning lookup a, then lookup b within a. I decided against that because '.' was already defined otherwise and am currently using (a..b). Before that I was using 'a.b' but I abandoned this because it ended up being too much expensive atom construction and parsing. In your new notation, the above could almost be done something like A.B = a.b, nb_getvar(A, AMap), extract AMap.B into result. That's what I would be inclined to do in Prolog, but I think this is not how you intend it to work. Ergo, confusion. Alan