Supports embedded conditionals when performing conditional compilation.
The code following the directive is compiled iff
Goal is true. If
Goal throws an error instead of either succeeding or failing, the
error is reported by the compiler and compilation of the enclosing source
file or entity is aborted. The goal is subjected to
goal expansion when the directive occurs
in a source file.
Conditional compilation goals cannot depend on predicate definitions contained in the same source file that contains the conditional compilation directives (as those predicates only become available after the file is successfully compiled and loaded).
Template and modes
:- if(current_prolog_flag(double_quotes, codes)). ... :- elif(current_prolog_flag(double_quotes, chars)). ... :- elif(current_prolog_flag(double_quotes, atom)). ... :- endif.