This is a simplistic Prolog-like example creating and querying relations between subjects and properties.
The following clause is recognized:
<subject> is <property>
The following special subjects act as query words and execute a query
what queries subjects about properties
who queries properties about subjects
For example,
Clause
Response
john is tall
none - sets a relation
john is old
none
what is john
john is tall and old
who is tall
john is tall
NB. prolog - creating and querying relations between subject and properties «state» «text-utilities» «query-words» «creating-relation» «execution» «example»
The state is defined with three arrays of subject, properties and the map of their relations.
NB. --------------------------------------------------------- NB. state WHO=: '' NB. subjects WHAT=: '' NB. properties MAP=: 0 0$0 NB. ($MAP) -: (#WHO),(#WHAT)
Text utilities help format the query output.
NB. ---------------------------------------------------------
NB. text utilities
copula=: 3 : 0
' ',~' ',> {&(;:'is are') 1 < #y
)
enlist=: 13 : ';}:,(<'', ''),.~y'
say=: 3 : 0
if. 0=#y do. 'none' return. end.
if. 1=#y do. ;y return. end.
(enlist }:y),' and ',(>_1{y)
)
Query words serve as special subjects
NB. ---------------------------------------------------------
NB. query words
what=: 3 : 0
y,(copula 1),say ((WHO i.<y){MAP)#WHAT
)
who=: 3 : 0
r=. ((WHAT i.<y){"1 MAP)#WHO
(say r),(copula r),y
)
Relations are created by looking up existing subjects and properties-- growing their lists if necessary--and marking the Boolean relation map.
NB. ---------------------------------------------------------
NB. creating relation
index=: 4 : 0
if. (#w) = i=. (w=. x~) i.<y do. (x)=: w,<y end. i
)
is=: 4 : 0
xy=. <('WHO'index x),('WHAT'index y)
MAP=: 1 xy } ((#WHO),#WHAT){.MAP
)
Parsing a clause identifies the subject and property parts, and then applies either one of defined routines as a special subject, or a generic is routine.
A group of clauses is executed each on a separate line, where the line is printed first and then passed for parsing, which prints a results if present.
NB. ---------------------------------------------------------
NB. execution
parse=: 3 : 0
's IS o'=. ;:y
if. 3=nc<s do. smoutput s~ o
else. s is o end.
empty''
)
run=: (parse [ smoutput@(' '&,)) ;. _2
The following example shows a typical session with a number of creation and querying clauses are used.
NB. --------------------------------------------------------- NB. example TEST=: 0 : 0 mike is tall john is tall peter is old john is old what is john john is smart what is john who is smart who is old mike is old who is old what is mike ) Note 'Test' run TEST )
The corresponding output looks like this:
run TEST mike is tall john is tall peter is old john is old what is john john is tall and old john is smart what is john john is tall, old and smart who is smart john is smart who is old john and peter are old mike is old who is old mike, john and peter are old what is mike mike is tall and old
The state at this point is
('';WHAT),WHO,.<"0 MAP
+-----+----+---+-----+
| |tall|old|smart|
+-----+----+---+-----+
|mike |1 |1 |0 |
+-----+----+---+-----+
|john |1 |1 |1 |
+-----+----+---+-----+
|peter|0 |1 |0 |
+-----+----+---+-----+See also
The Very Logo Way article on the www.elica.net web site
J Forum message chat/2009-August/002255 by Boyko Bantchev
Contributed by OlegKobchenko