[SOLVED] Add a fact iteractively in prolog?

[olejorgen]

Silly question, but how do I add a fact interactively in prolog. ie. directly in the interpreter.

(swi-prolog)

[pmasiar]

http://en.wikipedia.org/wiki/Prolog

Fact that you have cat, with name tom:

cat(tom).

[olejorgen]

?- cat(tom).
ERROR: Undefined procedure: cat/1


I suspect that it's somehow possible to change mode from "query" to "fact description" (?)

[bigboy_pdb]

Use assert.

So if you want to add the fact "cat(tom)." then use "assert(cat(tom)).". When you use the query "cat(tom).", Yes will be returned.

[olejorgen]

Thanks!

[bigboy_pdb]

You're welcome.

[Syntaxius]

An alternative, at leas in SICStus Proglog is:

?- [user] %this loads an interactive "file" where you can give interactive commands direct to the promt.
- cat(tom).
?- cat (tom).
- yes.