org.jpl7

Class Atom

java.lang.Object

org.jpl7.Term

org.jpl7.Atom

public class Atom
extends Term

Atom is a specialised Compound with zero arguments, representing a Prolog atom with the same name. An Atom is constructed with a String parameter (its name, unquoted), which cannot thereafter be changed.

 Atom a = new Atom("hello");
 

An Atom can be used (and re-used) as an argument of Compound Terms. Two Atom instances are equal (by equals()) iff they have equal names. 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.

See Also:

Term, Compound

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.String	name the name of this Compound
protected java.lang.String	type

Constructor Summary

Constructors

Constructor and Description
Atom(java.lang.String name)
Atom(java.lang.String name, java.lang.String type)

Method Summary

Modifier and Type	Method and Description
Term[]	args() the (zero) arguments of an Atom, as a (zero-length) Term[]
java.lang.String	atomType()
boolean	equals(java.lang.Object obj) Two Atoms are equal if they are identical (same object) or their respective names and blobTypes are equal
boolean	hasFunctor(java.lang.String name, int arity) Tests whether this Compound's functor has (String) 'name' and 'arity'.
boolean	isListNil() whether this Term denotes (syntax-specifically) an empty list
java.lang.String	name() the name (unquoted) of this Compound
protected void	put(java.util.Map<java.lang.String,term_t> varnames_to_vars, term_t term) To put an Atom in a term, we create a sequence of term_t references from the Term.terms_to_term_ts() method, and then use the Prolog.cons_functor_v() method to create a Prolog compound term.
java.lang.String	toString() an Atom's name is quoted if it is not a simple identifier.
int	type() returns the type of this term, as "Prolog.ATOM"
java.lang.String	typeName() returns the name of the type of this term, as "Atom"

Methods inherited from class org.jpl7.Term

arg, arity, bigValue, doubleValue, floatValue, getSubst, getSubsts, getTerm, getTerm, hasFunctor, hasFunctor, intValue, isAtom, isBigInteger, isCompound, isFloat, isInteger, isJFalse, isJNull, isJObject, isJRef, isJTrue, isJVoid, isListPair, isVariable, jrefToObject, listLength, longValue, objectToJRef, put, putParams, putParams, putParams1, putParams2, putTerm, putTerms, terms_equals, toString, toTermArray

Methods inherited from class java.lang.Object

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

Field Detail

name

protected final java.lang.String name

the name of this Compound

type

protected final java.lang.String type

Constructor Detail

Atom

public Atom(java.lang.String name)

Parameters:

name - the Atom's name (unquoted)

Atom

public Atom(java.lang.String name,
            java.lang.String type)

Method Detail

args

public Term[] args()

the (zero) arguments of an Atom, as a (zero-length) Term[]

Overrides:

args in class Term

Returns:

the (zero) arguments of an Atom, as a (zero-length) Term[]

atomType

public final java.lang.String atomType()

Overrides:

atomType in class Term

equals

public final boolean equals(java.lang.Object obj)

Two Atoms are equal if they are identical (same object) or their respective names and blobTypes are equal

Overrides:

equals in class java.lang.Object

Parameters:

obj - the Object to compare (not necessarily another Atom)

Returns:

true if the Object satisfies the above condition

hasFunctor

public final boolean hasFunctor(java.lang.String name,
                                int arity)

Tests whether this Compound's functor has (String) 'name' and 'arity'.

Overrides:

hasFunctor in class Term

Returns:

whether this Compound's functor has (String) 'name' and 'arity'

isListNil

public boolean isListNil()

whether this Term denotes (syntax-specifically) an empty list

Overrides:

isListNil in class Term

Returns:

whether this Term denotes (syntax-specifically) an empty list

name

public final java.lang.String name()

the name (unquoted) of this Compound

Overrides:

name in class Term

Returns:

the name (unquoted) of this Compound

put

protected void put(java.util.Map<java.lang.String,term_t> varnames_to_vars,
                   term_t term)

To put an Atom in a term, we create a sequence of term_t references from the Term.terms_to_term_ts() method, and then use the Prolog.cons_functor_v() method to create a Prolog compound term.

Specified by:

put in class Term

Parameters:

varnames_to_vars - A Map from variable names to Prolog variables

term - A (previously created) term_t which is to be set to a Prolog term corresponding to the Term subtype (Atom, Variable, Compound, etc.) on which the method is invoked.

toString

public java.lang.String toString()

an Atom's name is quoted if it is not a simple identifier.

Overrides:

toString in class java.lang.Object

Returns:

string representation of an Atom

type

public final int type()

returns the type of this term, as "Prolog.ATOM"

Specified by:

type in class Term

Returns:

the type of this term, as "Prolog.ATOM"

typeName

public java.lang.String typeName()

returns the name of the type of this term, as "Atom"

Specified by:

typeName in class Term

Returns:

the name of the type of this term, as "Atom"