CODEWITHSUNDEEP
prolog
omega
omega

Reputation: 43833

Getting ERROR: Undefined procedure in Prolog

In swi-prolog, I loaded a file which just has this:

% -*- Mode : Prolog -*- 

sunny.

In the terminal, if I do

?- sunny.

It says true. But if I do 

?- fff.

I expect it to say false, but it instead says

ERROR: Undefined procedure: fff/0 (DWIM could not correct goal)

This site http://www.doc.gold.ac.uk/~mas02gw/prolog_tutorial/prologpages/facts.html when doing the example with foggy., it says output should be no, but I get an error.

Does anyone know what's wrong?

Thanks

Upvotes: 0

Views: 1637

Answers (1)

g3muse
g3muse

Reputation: 121

You are telling prolog to execute a command that does not exist. If you were to have a file with only:

weather(sunny).

then running the command

weather(foggy).

would return false.

Upvotes: 2

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