Package net.hydromatic.morel.util

Class Unifier.Sequence

java.lang.Object

net.hydromatic.morel.util.Unifier.Sequence

All Implemented Interfaces:

Unifier.Term

Enclosing class:

Unifier

public static final class Unifier.Sequence
extends Object
implements Unifier.Term

A sequence of terms.

A sequence [a b c] is often printed "a(b, c)", as if "a" is the type of node and "b" and "c" are its children.

Field Summary

Fields

Modifier and Type	Field	Description
String	operator
List<Unifier.Term>	terms

Constructor Summary

Constructors

Constructor	Description
Sequence(String operator)
Sequence(String operator, List<Unifier.Term> terms)

Method Summary

Modifier and Type	Method	Description
<R> R	accept(Unifier.TermVisitor<R> visitor)
Unifier.Term	apply(Map<Unifier.Variable,Unifier.Term> substitutions)
void	checkCycle(Map<Unifier.Variable,Unifier.Term> map, Map<Unifier.Variable,Unifier.Variable> active)	Throws CycleException if expanding this term leads to a cycle.
boolean	contains(Unifier.Variable variable)
boolean	equals(Object obj)
private boolean	equalsShallow(Unifier.Sequence sequence)	Compares whether two sequences have the same terms.
int	hashCode()
private static <E> boolean	listEqual(List<E> list0, List<E> list1)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

operator

public final String operator

terms

public final List<Unifier.Term> terms

Constructor Detail

Sequence

Sequence(String operator,
         List<Unifier.Term> terms)

Sequence

Sequence(String operator)

Method Detail

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

toString

public String toString()

Overrides:

toString in class Object

apply

public Unifier.Term apply(Map<Unifier.Variable,Unifier.Term> substitutions)

Specified by:

apply in interface Unifier.Term

checkCycle

public void checkCycle(Map<Unifier.Variable,Unifier.Term> map,
                       Map<Unifier.Variable,Unifier.Variable> active)
                throws Unifier.CycleException

Description copied from interface: Unifier.Term

Throws CycleException if expanding this term leads to a cycle.

Specified by:

checkCycle in interface Unifier.Term

Throws:

Unifier.CycleException

equalsShallow

private boolean equalsShallow(Unifier.Sequence sequence)

Compares whether two sequences have the same terms. Compares addresses, not contents, to avoid hitting cycles if any of the terms are cyclic (e.g. "X = f(X)").

listEqual

private static <E> boolean listEqual(List<E> list0,
                                     List<E> list1)

contains

public boolean contains(Unifier.Variable variable)

Specified by:

contains in interface Unifier.Term

accept

public <R> R accept(Unifier.TermVisitor<R> visitor)

Specified by:

accept in interface Unifier.Term