Package edu.harvard.seas.pl.abcdatalog.util.substitution

Interface ConstOnlySubstitution

All Superinterfaces:

Substitution

All Known Implementing Classes:

ClauseSubstitution, SimpleConstSubstitution

public interface ConstOnlySubstitution
extends Substitution

A mapping from variables to constants. This is a restriction of a more general substitution, which is from variables to terms.

Method Summary

Modifier and Type	Method	Description
boolean	add(Variable x, Constant c)	Attempts to add a mapping to the substitution.
Constant	get(Variable x)	Retrieves the mapping of a variable.

Methods inherited from interface edu.harvard.seas.pl.abcdatalog.util.substitution.Substitution

apply

Method Details

get

Constant get(Variable x)

Retrieves the mapping of a variable.

Specified by:

get in interface Substitution

Parameters:

x - the variable

Returns:

the constant that the variable is bound to, or null if the variable is not in the substitution

add

boolean add(Variable x,
 Constant c)

Attempts to add a mapping to the substitution. Returns true if the mapping was made successfully (i.e., if the variable was not already mapped to another constant).

Parameters:

x - the variable

c - the constant

Returns:

whether the mapping was successfully added