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

Stabler - Lx 185/209 2003
(6) Example. Let’s use g1.pl again:
/*
* file: g1.pl
*/
:- op(1200,xfx,:˜).
ip :˜ [dp, i1]. i1 :˜ [i0, vp]. i0 :˜ [will].
dp :˜ [d1]. d1 :˜ [d0, np]. d0 :˜ [the].
np :˜ [n1]. n1 :˜ [n0].
n1 :˜ [n0, cp].
n0 :˜ [idea].
vp :˜ [v1]. v1 :˜ [v0]. v0 :˜ [suffice].
cp :˜ [c1]. c1 :˜ [c0, ip]. c0 :˜ [that].
With this grammar and llp.pl we get the following session:
| ?- [llp,g1,pp_tree].
{consulting /home/es/tex/185-00/llp.pl...}
{consulted /home/es/tex/185-00/llp.pl in module user, 20 msec 2000 bytes}
{consulting /home/es/tex/185-00/g1.pl...}
{consulted /home/es/tex/185-00/g1.pl in module user, 20 msec 2384 bytes}
{consulting /home/es/tex/185-00/pp_tree.pl...}
{consulted /home/es/tex/185-00/pp_tree.pl in module user, 10 msec 1344 bytes}
yes
| ?- [the,idea,will,suffice] ?˜ [ip]@[T].
T = ip/[dp/[d1/[d0/[the/[]],np/[n1/[...]]]],i1/[i0/[will/[]],vp/[v1/[v0/[...]]]]] ?
yes
| ?- ([the,idea,will,suffice] ?˜ [ip]@[T]), pp_tree(T).
ip /[
dp /[
d1 /[
d0 /[
the /[]],
np /[
n1 /[
n0 /[
idea /[]]]]]],
i1 /[
i0 /[
will /[]],
vp /[
v1 /[
v0 /[
suffice /[]]]]]]
T = ip/[dp/[d1/[d0/[the/[]],np/[n1/[...]]]],i1/[i0/[will/[]],vp/[v1/[v0/[...]]]]] ?
yes
| ?-
(7) Assessment of the LL strategy:
a. Unbounded memory requirements on simple left branching.
b. Stupid about left branches – recursion in left branches produces infinite search spaces.
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