Package gnu.mapping

Class PropertyLocation

java.lang.Object

gnu.mapping.Location<Object>

gnu.mapping.PropertyLocation

public class PropertyLocation
extends Location<Object>

Used to implement Lisp-style "property lists". A PropertyLocation is a location whose value is the car of a property list. This class also contains a number of static methods useful for working with property lists.

Field Summary

Fields inherited from class gnu.mapping.Location

UNBOUND

Constructor Summary

Constructors

Constructor	Description
PropertyLocation()

Method Summary

Modifier and Type	Method	Description
Object	get()	Get the current value of this location.
static Object	getProperty(Object symbol, Object property, Object defaultValue)	Gets a property value associated with an object.
static Object	getProperty(Object symbol, Object property, Object defaultValue, Environment env)	Gets a property value associated with an object.
static Object	getPropertyList(Object symbol)	Get the property list associated with object in the current Environment.
static Object	getPropertyList(Object symbol, Environment env)	Get the property list assocated with an object in a given Environment.
boolean	isBound()
static Object	plistGet(Object plist, Object prop, Object dfault)	Given a property list and a key, find the corresponding property value.
static Object	plistPut(Object plist, Object prop, Object value)	Modify and add a property binding to a property list.
static Object	plistRemove(Object plist, Object prop)	Remove a property binding from a property list.
static void	putProperty(Object symbol, Object property, Object newValue)	Sets a property value associated with an object.
static void	putProperty(Object symbol, Object property, Object newValue, Environment env)
static boolean	removeProperty(Object symbol, Object property)	Remove a property associated with an object.
static boolean	removeProperty(Object symbol, Object property, Environment env)	Remove a properaty assocatied with an object.
void	set(Object newValue)
static void	setPropertyList(Object symbol, Object plist)	Set the property list assocated with an object in a given Environment.
static void	setPropertyList(Object symbol, Object plist, Environment env)	Set the property list assocated with an object in a given Environment.

Methods inherited from class gnu.mapping.Location

define, entered, get, getBase, getKeyProperty, getKeySymbol, getValue, isConstant, make, make, make, print, setRestore, setValue, setWithSave, toString, undefine

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PropertyLocation

public PropertyLocation()

Method Detail

get

public final Object get()

Description copied from class: Location

Get the current value of this location.

Specified by:

get in class Location<Object>

isBound

public boolean isBound()

Specified by:

isBound in class Location<Object>

set

public final void set(Object newValue)

Specified by:

set in class Location<Object>

getPropertyList

public static Object getPropertyList(Object symbol,
                                     Environment env)

Get the property list assocated with an object in a given Environment.

Parameters:

symbol - Usually but not necessarily a Symbol. (A String is not converted a Symbol by this method.)

getPropertyList

public static Object getPropertyList(Object symbol)

Get the property list associated with object in the current Environment. Corresponds to Common Lisp's symbol-plist function.

Parameters:

symbol - Usually but not necessarily a Symbol. (A String is not converted a Symbol by this method.)

setPropertyList

public static void setPropertyList(Object symbol,
                                   Object plist,
                                   Environment env)

Set the property list assocated with an object in a given Environment. This function should be avoided, since a Symbol's property list may be used by unknown classes. It also can be slow.

Parameters:

symbol - Usually but not necessarily a Symbol. (A String is not converted a Symbol by this method.)

setPropertyList

public static void setPropertyList(Object symbol,
                                   Object plist)

Set the property list assocated with an object in a given Environment. Corresponds to Common Lisp's (setf symbol-plist) function.

See Also:

setPropertyList(Object,Object,Environment)

getProperty

public static Object getProperty(Object symbol,
                                 Object property,
                                 Object defaultValue,
                                 Environment env)

Gets a property value associated with an object.

Parameters:

symbol - Usually a Symbol, but can be any Object. A String is converted to a Symbol using env.getSymbol(). Symbols require a constant-type hash lookup; other object are searched linearly.

getProperty

public static Object getProperty(Object symbol,
                                 Object property,
                                 Object defaultValue)

Gets a property value associated with an object. Corresponds to Common Lisp's get function.

See Also:

getProperty(Object,Object,Object,Environment)

putProperty

public static void putProperty(Object symbol,
                               Object property,
                               Object newValue,
                               Environment env)

putProperty

public static void putProperty(Object symbol,
                               Object property,
                               Object newValue)

Sets a property value associated with an object. Corresponds to Common Lisp's (setf get) function.

removeProperty

public static boolean removeProperty(Object symbol,
                                     Object property,
                                     Environment env)

Remove a properaty assocatied with an object.

removeProperty

public static boolean removeProperty(Object symbol,
                                     Object property)

Remove a property associated with an object. Corresponds to Common Lisp's remprop function.

plistGet

public static Object plistGet(Object plist,
                              Object prop,
                              Object dfault)

Given a property list and a key, find the corresponding property value.

plistPut

public static Object plistPut(Object plist,
                              Object prop,
                              Object value)

Modify and add a property binding to a property list.

Returns:

The updated property list.

plistRemove

public static Object plistRemove(Object plist,
                                 Object prop)

Remove a property binding from a property list.

Returns:

The updated property list.