Rule preprocessor - axkr/symja_android_library GitHub Wiki

• Translate rewriting rules
• Using embedded rules

Translate rewriting rules

The RulePreprocessor.java can be used to translate files with term rewriting rules from the /rules folder into Java interfaces in the package org.matheclipse.core.reflection.system.rules

For example for the Cos function the rules can be added like this:

...
      import org.matheclipse.core.reflection.system.rules.CosRules;
...

      private final static class Cos extends ... implements ..., CosRules  {
...

...
		@Override
		public IAST getRuleAST() {
			return RULES;
		}

		@Override
		public void setUp(final ISymbol newSymbol) {
			newSymbol.setAttributes(ISymbol.LISTABLE | ISymbol.NUMERICFUNCTION);
			// call AbstractFunctionEvaluator#setUp() to initialize rules
			super.setUp(newSymbol);
		}
      }

Using embedded rules

With the ExprPreprocessor.java tool you can convert embedded math expressions into Java source code.

In the example from the TrigToExp function the Symja expression 2/(E^x-E^(-x))

 MATCHER.caseOf(Csch(x_), //
  		x -> // [$ 2/(E^x-E^(-x)) $]
 		F.Null); // $$);

will be converted into the Symja Java source code

 MATCHER.caseOf(Csch(x_), //
  		x -> // [$ 2/(E^x-E^(-x)) $]
 		F.Times(F.C2, F.Power(F.Plus(F.Negate(F.Power(F.E, F.Negate(x))), F.Power(F.E, x)), -1))); // $$);

Note: the ); characters behind the closing // $$ tag will be appended to the generated source code.

After running the ExprPreprocessor you can use the Eclipse menu "Copy qualified name" for the file which you would like to convert. Input the qualified Java file name for converting the expressions into Java source and refresh the file in the Eclipse editor.

▶ /java_codegen/src/main/java/org/matheclipse/core/reflection/system/TrigToExp.java