When compiling a source file to a .ql file, remember that clauses
are loaded and directives are executed at run time, not at
compile time. Only predicate declarations are processed at compile
time. For instance, it does not work to include operator declarations
or clauses of user:term_expansion/[2,4] or
user:goal_expansion/3 or any auxiliary predicates that they might
need, and rely on the new transformations to be effective for subsequent
clauses of the same file or subsequent files of the same compilation.
Any directives or clauses that affect the compile-time environment
must be loaded prior to compiling source files to .ql files. This
also holds for meta-predicates called by the source files but defined
elsewhere, for module name expansion to work correctly. If this
separation into files is unnatural or inconvenient, one can easily
ensure that the compile-time environment is up to date by doing:
| ?- ensure_loaded(Files), fcompile(Files).
Since module name expansion takes place at compile time, the module
into which the file is to be loaded must be known when compiling to
.ql files. This is no problem for module-files because the module
name is picked from the module declaration. When non-module-files are
compiled, the file name may be prefixed with the module name that is
to be used for expansion:
| ?- fcompile(Module:Files).
If an .ql file is loaded into a different module from which it was
compiled for, a warning is issued.