PPT Slide
[ e , el , e2 , e3 , e4 ]
[ e1 , e , e2 , e3 , e4 ]
[ e1 , e2 , e , e3 , e4 ]
[ e1 , e2 , e3 , e , e4 ]
[ e1 , e2 , e3 , e4 , e ]
insert( X , L , [ X | L ] ) .
insert( X , [ H | T ] , [ H | U ] ) : - insert( X , T , U ).
If you only ask for one solution, it will only use the first rule.
| ? - insert( a , [ b , c , d ] , Ans ) .
For a second answer, it goes on to the next rule.
| ? - insert( a , [ b | [ c , d ] ] , [ b | U ] )
insert( a , [ c , d ] , U2 )
insert( a , [ c , d ] , [ a , c , d ] )
insert( a , [ b | [ c , d ] ] , [ b , a , c , d ] )
Inserting an Element ( Somewhere ) in a List