How to use pattern-matching

Overview

If you want to manipulate IExpr objects in Symja the dedicated design pattern is the visitor.

The visitor pattern is implemented in this package:

• org.matheclipse.core.visit

To simplify the manipulation of IExpr objects a pattern matching mechanism has been designed in the Matcher and Tester classes.

import static org.matheclipse.core.expression.F.*;
import org.matheclipse.core.patternmatching.Matcher;

  Matcher matcher = new Matcher();
  matcher.caseOf(Sin(x_), D(Sin(x), x));
  
  
  // print Cos(y)
  System.out.println(matcher.apply(Sin(y)));