6.2.90. not

is true if its argument is not true

SYNOPSIS

not( test_predicate )

SYNTAX

not(Goal)(i)

ARGUMENTS

void(Goal) (i) Term to be tested.

DESCRIPTION

This is a standard prolog built-in. Not succeeds if a call () to Goal would not.
NOTE: there are to versions of not(). If the argument is bound at compile time, i.e. is not a variable, the compiler handles not. If the argument is a variable, not uses call(), thus the same restrictions apply!

EXAMPLE

read(X),
( char(X), write("Character"),nl ;
  integer(X), write("Integer"),nl ;
  not( isname ), write("Error"),nl,! ;
  write("Is a Token\n")
).

ERRORS

No runtime errors.

LAYERS

prolog-process, client-server, object

RELATED PREDICATES

call