Availability:built-in
expand_term(+Term1,
-Term2)This predicate is normally called by the compiler on terms read from the
input to perform preprocessing. It consists of four steps, where each
step processes the output of the previous step.
- Test conditional compilation directives and translate all input to
[]
if we are in a‘false branch’of the conditional compilation.
See section 4.3.1.2.
- Call term_expansion/2.
This predicate is first tried in the module that is being compiled and
then in modules from which this module inherits according to default_module/2.
The output of the expansion in a module is used as input for the next
module. Using the default setup and when compiling a normal application
module M, this implies expansion is executed in M,
user
and finally in system
. Library modules inherit directly
from system
and can thus not be re-interpreted by term
expansion rules in user
.
- Call DCG expansion (dcg_translate_rule/2).
- Call expand_goal/2
on each body term that appears in the output of the previous steps.