Standard Predicates
Execution Control
true
fail
repeat
trace
notrace
call
Database Handling
clause
retract
assert
consult
reconsult
save
op
list
File System
tell
telling
told
see
seeing
seen
eof
Input, Output
write
nl
display
read
readln
readchar
Unification
arg
functor
is
integer
var
nonvar
Other Predicates
concat
str_int
str_atom
char_int
date
time
Extended Predicates
fronttoken
str_toklist