clips

Why do some CLIPS function names end with $?

Why do some builtin function names in CLIPS end with a $, such as explode$ ? What is the significance of this?

Solution

  • The $ indicates they either accept or return a multifield value. Multifield variables begin with a $, so that is why that particular character is used. If you use the apropos function, you can quickly get a list of functions containing the $ character.

             CLIPS (6.4.1 4/8/23)
CLIPS> (apropos $)
slot-replace$
delete$
expand$
slot-direct-replace$
rest$
slot-direct-insert$
delete-member$
explode$
slot-delete$
first$
progn$
replace-member$
insert$
member$
nth$
slot-insert$
union$
implode$
slot-direct-delete$
replace$
create$
length$
difference$
intersection$
subseq$
CLIPS>