65 lines
2.2 KiB
Java
65 lines
2.2 KiB
Java
package it.cavallium.warppi.math.rules.dsl.patterns;
|
|
|
|
import it.cavallium.warppi.math.Function;
|
|
import it.cavallium.warppi.math.MathContext;
|
|
import it.cavallium.warppi.math.rules.dsl.Pattern;
|
|
import it.cavallium.warppi.math.rules.dsl.UndefinedSubFunctionException;
|
|
|
|
import java.util.Map;
|
|
import java.util.Objects;
|
|
import java.util.stream.Stream;
|
|
|
|
/**
|
|
* Matches and generates any function as a named sub-function.
|
|
* <p>
|
|
* For a <code>Function</code> to match a <code>Pattern</code>, all <code>SubFunctionPattern</code>s with the same name
|
|
* must capture equal sub-functions (according to the <code>equals</code> method).
|
|
* For example, the <code>x + x</code> <code>Pattern</code> matches <code>2 + 2</code> and <code>2 + 2.0</code>,
|
|
* but not <code>2 + 3</code>, while the <code>x + y</code> <code>Pattern</code> matches all three <code>Function</code>s.
|
|
*/
|
|
public class SubFunctionPattern implements Pattern {
|
|
private final String name;
|
|
|
|
public SubFunctionPattern(final String name) {
|
|
this.name = name;
|
|
}
|
|
|
|
@Override
|
|
public boolean match(final Function function, final Map<String, Function> subFunctions) {
|
|
final Function existingSubFunction = subFunctions.putIfAbsent(name, function);
|
|
return existingSubFunction == null || existingSubFunction.equals(function);
|
|
}
|
|
|
|
/**
|
|
* @throws UndefinedSubFunctionException if the <code>subFunctions</code> <code>Map</code> doesn't contain a
|
|
* sub-function with the name specified in this
|
|
* <code>SubFunctionPattern</code>'s constructor.
|
|
*/
|
|
@Override
|
|
public Function replace(final MathContext mathContext, final Map<String, Function> subFunctions) {
|
|
if (!subFunctions.containsKey(name)) {
|
|
throw new UndefinedSubFunctionException(name);
|
|
}
|
|
return subFunctions.get(name);
|
|
}
|
|
|
|
@Override
|
|
public Stream<SubFunctionPattern> getSubFunctions() {
|
|
return Stream.of(this);
|
|
}
|
|
|
|
@Override
|
|
public boolean equals(final Object o) {
|
|
if (!(o instanceof SubFunctionPattern)) {
|
|
return false;
|
|
}
|
|
final SubFunctionPattern other = (SubFunctionPattern) o;
|
|
return name.equals(other.name);
|
|
}
|
|
|
|
@Override
|
|
public int hashCode() {
|
|
return Objects.hash(name);
|
|
}
|
|
}
|