Add method to get sub-functions from patterns

core/src/main/java/it/cavallium/warppi/math/rules/dsl/Pattern.java

@@ -2,9 +2,11 @@ package it.cavallium.warppi.math.rules.dsl;
 
 import it.cavallium.warppi.math.Function;
 import it.cavallium.warppi.math.MathContext;
+import it.cavallium.warppi.math.rules.dsl.patterns.SubFunctionPattern;
 
 import java.util.Map;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Recognizes and generates functions of some specific shape.
@@ -27,4 +29,10 @@ public interface Pattern {
 	 * @return The resulting function.
 	 */
 	Function replace(MathContext mathContext, Map<String, Function> subFunctions);
+
+	/**
+	 * @return The (possibly empty) <code>Set</code> of all sub-function patterns
+	 *         found within this pattern and its children.
+	 */
+	Set<SubFunctionPattern> getSubFunctions();
 }

core/src/main/java/it/cavallium/warppi/math/rules/dsl/PatternUtils.java

@@ -3,10 +3,10 @@ package it.cavallium.warppi.math.rules.dsl;
 import it.cavallium.warppi.math.Function;
 import it.cavallium.warppi.math.FunctionOperator;
 import it.cavallium.warppi.math.functions.Subtraction;
+import it.cavallium.warppi.math.rules.dsl.patterns.SubFunctionPattern;
 
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Optional;
+import java.util.*;
+import java.util.stream.Collectors;
 
 /**
  * Contains helper methods which are useful for writing patterns.
@@ -71,4 +71,17 @@ public class PatternUtils {
 						.flatMap(match2 -> mergeMatches(match1, match2))
 				);
 	}
+
+	/**
+	 * Gathers all sub-function patterns from multiple patterns.
+	 *
+	 * @param patterns The patterns from which sub-functions are gathered.
+	 * @return The union of the return values of {@link Pattern#getSubFunctions()} for each pattern.
+	 */
+	public static Set<SubFunctionPattern> getSubFunctionsFrom(final Pattern... patterns) {
+		return Arrays.stream(patterns)
+				.map(Pattern::getSubFunctions)
+				.flatMap(Set::stream)
+				.collect(Collectors.toSet());
+	}
 }

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/ArcCosinePattern.java

@@ -9,6 +9,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates the arccosine of another pattern.
@@ -33,6 +34,11 @@ public class ArcCosinePattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return argument.getSubFunctions();
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof ArcCosinePattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/ArcSinePattern.java

@@ -9,6 +9,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates the arcsine of another pattern.
@@ -33,6 +34,11 @@ public class ArcSinePattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return argument.getSubFunctions();
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof ArcSinePattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/ArcTangentPattern.java

@@ -9,6 +9,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates the arctangent of another pattern.
@@ -33,6 +34,11 @@ public class ArcTangentPattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return argument.getSubFunctions();
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof ArcTangentPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/ConstantPattern.java

@@ -5,10 +5,7 @@ import it.cavallium.warppi.math.MathContext;
 import it.cavallium.warppi.math.functions.Variable;
 import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
+import java.util.*;
 
 /**
  * Matches and generates a specific symbolic constant.
@@ -35,6 +32,11 @@ public class ConstantPattern extends VisitorPattern {
 		return new Variable(mathContext, symbol, Variable.V_TYPE.CONSTANT);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return Collections.emptySet();
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof ConstantPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/CosinePattern.java

@@ -9,6 +9,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates the cosine of another pattern.
@@ -33,6 +34,11 @@ public class CosinePattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return argument.getSubFunctions();
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof CosinePattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/DivisionPattern.java

@@ -10,6 +10,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates a division of two other patterns.
@@ -37,6 +38,11 @@ public class DivisionPattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return PatternUtils.getSubFunctionsFrom(dividend, divisor);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof DivisionPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/EquationPattern.java

@@ -11,6 +11,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates an equation of two other patterns.
@@ -38,6 +39,11 @@ public class EquationPattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return PatternUtils.getSubFunctionsFrom(left, right);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof EquationPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/EquationsSystemPattern.java

@@ -7,10 +7,7 @@ import it.cavallium.warppi.math.rules.dsl.Pattern;
 import it.cavallium.warppi.math.rules.dsl.PatternUtils;
 import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Optional;
+import java.util.*;
 
 /**
  * Matches and generates a system of equations of multiple other patterns.
@@ -48,6 +45,11 @@ public class EquationsSystemPattern extends VisitorPattern {
 		return new EquationsSystem(mathContext, functions);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return PatternUtils.getSubFunctionsFrom(patterns);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof EquationsSystemPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/LogarithmPattern.java

@@ -10,6 +10,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates a logarithm of base and argument patterns.
@@ -37,6 +38,11 @@ public class LogarithmPattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return PatternUtils.getSubFunctionsFrom(base, argument);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof LogarithmPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/MultiplicationPattern.java

@@ -10,6 +10,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates a multiplication of two other patterns.
@@ -37,6 +38,11 @@ public class MultiplicationPattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return PatternUtils.getSubFunctionsFrom(left, right);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof MultiplicationPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/NegativePattern.java

@@ -9,6 +9,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates the negative of another pattern.
@@ -33,6 +34,11 @@ public class NegativePattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return inner.getSubFunctions();
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof NegativePattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/NumberPattern.java

@@ -6,10 +6,7 @@ import it.cavallium.warppi.math.functions.Number;
 import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 
 import java.math.BigDecimal;
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
+import java.util.*;
 
 /**
  * Matches and generates a specific number.
@@ -35,6 +32,11 @@ public class NumberPattern extends VisitorPattern {
 		return new Number(mathContext, value);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return Collections.emptySet();
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof NumberPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/PowerPattern.java

@@ -10,6 +10,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates a power (exponentiation) of base and exponent patterns.
@@ -37,6 +38,11 @@ public class PowerPattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return PatternUtils.getSubFunctionsFrom(base, exponent);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof PowerPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/RootPattern.java

@@ -13,6 +13,7 @@ import java.math.BigDecimal;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates a root of degree and radicand patterns.
@@ -51,6 +52,11 @@ public class RootPattern extends VisitorPattern {
 		}
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return PatternUtils.getSubFunctionsFrom(degree, radicand);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof RootPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/SinePattern.java

@@ -9,6 +9,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates the sine of another pattern.
@@ -33,6 +34,11 @@ public class SinePattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return argument.getSubFunctions();
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof SinePattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/SubFunctionPattern.java

@@ -4,10 +4,7 @@ import it.cavallium.warppi.math.Function;
 import it.cavallium.warppi.math.MathContext;
 import it.cavallium.warppi.math.rules.dsl.Pattern;
 
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
+import java.util.*;
 
 /**
  * Matches and generates any function as a named sub-function.
@@ -31,6 +28,11 @@ public class SubFunctionPattern implements Pattern {
 		return subFunctions.get(name);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return Collections.singleton(this);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof SubFunctionPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/SubtractionPattern.java

@@ -10,6 +10,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates a subtraction of two other patterns.
@@ -37,6 +38,11 @@ public class SubtractionPattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return PatternUtils.getSubFunctionsFrom(left, right);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof SubtractionPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/SumPattern.java

@@ -10,6 +10,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates a sum of two other patterns.
@@ -37,6 +38,11 @@ public class SumPattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return PatternUtils.getSubFunctionsFrom(left, right);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof SumPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/SumSubtractionPattern.java

@@ -10,6 +10,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates a sum/subtraction (±) of two other patterns.
@@ -37,6 +38,11 @@ public class SumSubtractionPattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return PatternUtils.getSubFunctionsFrom(left, right);
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof SumSubtractionPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/TangentPattern.java

@@ -9,6 +9,7 @@ import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.Set;
 
 /**
  * Matches and generates the tangent of another pattern.
@@ -33,6 +34,11 @@ public class TangentPattern extends VisitorPattern {
 		);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return argument.getSubFunctions();
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		if (!(o instanceof TangentPattern)) {

core/src/main/java/it/cavallium/warppi/math/rules/dsl/patterns/UndefinedPattern.java

@@ -5,9 +5,7 @@ import it.cavallium.warppi.math.MathContext;
 import it.cavallium.warppi.math.functions.Undefined;
 import it.cavallium.warppi.math.rules.dsl.VisitorPattern;
 
-import java.util.HashMap;
-import java.util.Map;
-import java.util.Optional;
+import java.util.*;
 
 /**
  * Matches and generates <code>Undefined</code>.
@@ -23,6 +21,11 @@ public class UndefinedPattern extends VisitorPattern {
 		return new Undefined(mathContext);
 	}
 
+	@Override
+	public Set<SubFunctionPattern> getSubFunctions() {
+		return Collections.emptySet();
+	}
+
 	@Override
 	public boolean equals(final Object o) {
 		return o instanceof UndefinedPattern;