logtalk_load_context/2¶
Description¶
logtalk_load_context(Key, Value)
Provides access to the Logtalk compilation/loading context. The following keys are currently supported:
entity_identifier
- identifier of the entity being compiled if anyentity_prefix
- internal prefix for the entity compiled codeentity_type
- returns the valuemodule
when compiling a module as an objectsource
- full path of the source file being compiledfile
- the actual file being compiled, different fromsource
only when processing aninclude/1
directivebasename
- source file basenamedirectory
- source file directorystream
- input stream being used to read source file termstarget
- the full path of the intermediate Prolog fileflags
- the list of the explicit flags used for the compilation of the source fileterm
- the source file term being compiledterm_position
- the position of the term being compiled (StartLine-EndLine
)variable_names
- the variable names of the term being compiled ([Name1=Variable1, ...]
)
The logtalk_load_context/2
predicate can also be called
initialization/1 directives in a source file.
A common scenario is to use the directory
key to define
library aliases.
Warning
The term_position
key is only supported in
backend Prolog compilers
that provide access to the start and end lines of a read term.
Currently, any variables in the values of the term
and
variable_names
keys are not shared with, respectively, the term
and goal arguments of the term_expansion/2 and
goal_expansion/2 methods.
Using the variable_names
key requires calling the standard built-in
predicate term_variables/2
on the term read and unifying the term
variables with the variables in the names list. This, however, may rise
portability issues with those Prolog compilers that don’t return the
variables in the same order for the term_variables/2
predicate and
the option variable_names/1
of the read_term/3
built-in
predicate, which is used by the Logtalk compiler to read source files.
Modes and number of proofs¶
logtalk_load_context(?atom, -nonvar) - zero_or_more
Errors¶
(none)
Examples¶
term_expansion(Term, ExpandedTerms) :-
...
logtalk_load_context(entity_identifier, Entity),
....
:- initialization((
logtalk_load_context(directory, Directory),
assertz(logtalk_library_path(my_app, Directory))
)).
See also