Notes on computational linguistics.pdf - UCLA Department of ...

Stabler - Lx 185/209 2003
’[0]’([n|Rest]) :˜ [n,’[0n]’(Rest)].
’[0n]’([]) :˜ [].
’[m]’(Rest) :˜ [’&’,’[m&]’(Rest)].
’[m&]’(Rest) :˜ [t,’[m&t]’(Rest)].
’[m&t]’([m,a,t]) :˜ [].
’[m&t]’([m,a,t,t]) :˜ [].
’[m&t]’([’M’,a,t,t]) :˜ [].
With can test this grammar this way:
2 ?- [goodprog].
% goodprog compiled 0.00 sec, 2,760 bytes
Yes
3 ?- ([’D’,’@’] ?˜ [lex(W)]).
W = [t, h, e] ;
No
4 ?- ([m,’&’,t] ?˜ [lex(W)]).
W = [m, a, t] ;
W = [m, a, t, t] ;
W = [’M’, a, t, t] ;
No
5 ?- ([m,’&’,t,’D’] ?˜ [lex(W)]).
No
6 ?-
(It’s always a good idea to test your axioms with both positive and negative cases like this!)
Now let’s extend this to part b of the problem. We can use the same syntax again, and simply modify the
“scan” to notice when we are trying to find a syntactic atom – now represented by a list of characters – then
we should try to parse it as a sequence of phones using our transducer.
[] ?˜ [].
(S0 ?˜ Goals0) :- infer(S0,Goals0,S,Goals), (S ?˜ Goals).
infer(S,[A|C],S,DC) :- (A :˜ D), append(D,C,DC). % ll
infer([W|S],[W|C],S,C). % scan
infer(Phones,[[Char|Chars]|C],Rest,C) :append([Phon|Phons],Rest,Phones),
([Phon|Phons] ?˜ [lex([Char|Chars])]). % minor change here
Now we can test the result.
1 ?- [goodprog].
% goodprog compiled 0.00 sec, 6,328 bytes
Yes
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