jpl
Class JPL
public
class
JPL
extends Object
The jpl.JPL class contains methods which allow (i) inspection and alteration
of the "default" initialisation arguments (ii) explicit initialisation
(iii) discovery of whether the Prolog engine is already initialised,
and if so, with what arguments.
The Prolog engine must be initialized
before any queries are made, but this will happen automatically
(upon the first call to a Prolog FLI routine) if it has not already
been done explicitly.
Copyright (C) 2004 Paul Singleton
Copyright (C) 1998 Fred Dushin
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Library Public License for more details.
Method Summary |
static String[] | getActualInitArgs()
Returns, in an array of String, the sequence of command-line
arguments that were actually used when the Prolog engine was formerly initialised.
|
static String[] | getDefaultInitArgs()
Returns, in an array of String, the sequence of command-line
arguments that would be used if the Prolog engine were to be initialised now.
|
static void | halt()
Terminates the Prolog session.
Note. This method calls the FLI halt() method with a
status of 0, but the halt method currently is a no-op in SWI. |
static boolean | init(String[] args)
Initializes the Prolog engine, using the String argument
parameters passed. |
static boolean | init()
Initialises the Prolog engine using the current default initialisation parameters,
and returns 'true' (or 'false' if already initialised). |
static boolean | isTag(String s)
whether the String arg is a plausible tag, e.g. |
static void | main(String[] args) |
static Term | newJRef(Object obj)
returns a new Term instance which represents the given object |
static void | setDefaultInitArgs(String[] args)
Specifies, in an array of String, the sequence of command-line
arguments that should be used if the Prolog engine is subsequently initialised.
|
static void | setDTMMode(boolean dtm)
Sets the global "dont-tell-me" mode (default value: true).
|
static Version | version()
Returns (as a Version) an identification of this version of JPL. |
static String | version_string()
Returns a String (eg "3.0.0-alpha") identifying this version of JPL. |
public static final
Term JFALSE
public static final
Term JNULL
public static final
Term JTRUE
public static final
Term JVOID
public static String[] getActualInitArgs()
Returns, in an array of String, the sequence of command-line
arguments that were actually used when the Prolog engine was formerly initialised.
This method returns null if the Prolog engine has not yet been initialised,
and thus may be used to test this condition.
Returns: actual initialization arguments
public static String[] getDefaultInitArgs()
Returns, in an array of String, the sequence of command-line
arguments that would be used if the Prolog engine were to be initialised now.
Returns null if the Prolog VM has already been initialised (in which
case the default init args are irrelevant and the actual init args are of interest)
Returns: current default initialisation arguments, or null if already initialised
See Also: JPL
public static void halt()
Deprecated:
Terminates the Prolog session.
Note. This method calls the FLI halt() method with a
status of 0, but the halt method currently is a no-op in SWI.
public static boolean init(String[] args)
Initializes the Prolog engine, using the String argument
parameters passed. This method need be called only if you want to both
(i) initialise the Prolog engine with parameters other than the default ones
and (ii) force initialisation to occur
(rather than allow it to occur automatically at the first query).
For parameter options, consult your local
Prolog documentation. The parameter values are passed directly
to initialization routines for the Prolog environment.
This method must be called before making any queries.
Parameters: args Initialization parameter list
public static boolean init()
Initialises the Prolog engine using the current default initialisation parameters,
and returns 'true' (or 'false' if already initialised).
public static boolean isTag(String s)
whether the String arg is a plausible tag, e.g. "J#0123456789".
public static void main(String[] args)
public static
Term newJRef(Object obj)
returns a new Term instance which represents the given object
public static void setDefaultInitArgs(String[] args)
Specifies, in an array of String, the sequence of command-line
arguments that should be used if the Prolog engine is subsequently initialised.
Parameters: args new default initialization arguments
public static void setDTMMode(boolean dtm)
Sets the global "dont-tell-me" mode (default value: true).
When 'true', bindings will *not* be returned for any variable (in a Query's goal)
whose name begins with an underscore character (except for "anonymous" variables,
i.e. those whose name comprises just the underscore character, whose bindings are never returned).
When 'false', bindings are returned for *all* variables except anonymous ones;
this mode may be useful when traditional top-level interpreter behaviour is wanted,
e.g. in a Java-based Prolog IDE or debugger.
This method should be regarded as experimental, and may subsequently be deprecated
in favour of some more general mechanism for setting options, perhaps per-Query and
per-call as well as globally.
Parameters: dtm new "dont-tell-me" mode value
public static Version version()
Returns (as a Version) an identification of this version of JPL.
Returns: the running version of JPL.
public static String version_string()
Returns a String (eg "3.0.0-alpha") identifying this version of JPL.
Returns: a String (eg "3.0.0-alpha") identifying this version of JPL.