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load_files/[1,2]
load_files(+Files)
load_files(+Files, +Options)
[+Files]
Loads the specified Prolog source and/or object file(s) into memory. Subsumes all other load predicates.
file_spec or list of file_spec, must be ground
A file specification or a list of file specifications; extensions optional.
list of term, must be ground
A list of zero or more options of the form:
if(X)
true
(the default) to always load, or changed
to
load only if the file has not yet been loaded or if it has
been modified since it was last loaded. A non-module file
is not considered to have been previously loaded if it was
loaded into a different module. The file specification user
is
never considered to have been previously loaded.
when(When)
always
(the default) to always load, or compile_time
to load only if the goal is not in the scope of another
load_files/[1,2]
directive occurring in a PO file.
The latter is intended for use when the file only defines predicates that are needed for proper term or goal expansion during compilation of other files.
load_type(LoadType)
source
to load source files only, object
to
load object (PO) files only,
or latest
(the default) to load any type of file, whichever is
newest. If the file specification is user
, then source
is forced.
imports(Imports)
all
(the default) to import all exported
predicates if the file is a module file, or a list of
predicates to import.
compilation_mode(Mode)
compile
to translate into compiled code, consult
to
translate into static, interpreted code, or
assert_all
to translate into dynamic, interpreted
code.
The default is the compilation mode of any ancestor
load_files/[1,2]
goal, or compile
otherwise. Note
that Mode has no effect when a PO file is
loaded, and that it is recommended to use assert_all
in
conjunction with load_type(source)
, to ensure that the source
file will be loaded even in the presence of a PO file.
In addition the open/4
options encoding/1
, encoding_signature/1
and
eol/1
can be specified. These will be used if the Prolog code is
loaded from a source file. See mpg-ref-open, for details.
load_files/[1,2]
reads Prolog clauses, in source or precompiled
form, and adds them to the Prolog database, after first deleting any previous
versions of the predicates they define. Clauses for a single predicate must
all be in the same file unless that predicate is declared to be multifile
.
If a source file contains directives, that is, terms with principal
functor :-/1
or ?-/1
, then these are executed as they
are encountered. Initialization goals specified with
initialization/1
are executed after the load.
A non-module source file can be loaded into any module by load_files/[1,2]
,
but the module of the predicates in a precompiled file is fixed at the time it is
created.
instantiation_error
Files or Options is not ground.
type_error
In Files or Options.
domain_error
Illegal option in Options.
existence_error
A specified file does not exist. If the fileerrors
flag is off
, then the
predicate fails instead of raising this exception.
permission_error
A specified file not readable. If the fileerrors
flag is off
, then the
predicate fails instead of raising this exception.
While loading clauses from a PO file, clauses for an existing multifile predicate were encountered, but were compiled in a way different from the existing clauses. In this case, the existing clauses remain untouched, the multifile clauses from the PO file are simply ignored, the load continues, and an exception is raised at the end.
Several of the other built-in predicates of this category could
be defined in terms of load_files/2
:
[File|Files] :- load_files([File|Files]). consult(Files) :- load_files(Files, [load_type(source),compilation_mode(consult)]). ensure_loaded(Files) :- load_files(Files, [if(changed)]). use_module(File) :- load_files(File, [if(changed)]). use_module(File, Imports) :- load_files(File, [if(changed),imports(Imports)]).
Code that is only needed at compile-time, e.g. for operator declarations or compile-time expansion, is conveniently loaded with the following idiom:
:- load_files(library(obj_decl), [when(compile_time), if(changed)]).