org.lsmp.djep.xjep

Class SubstitutionVisitor

java.lang.Object

org.lsmp.djep.xjep.DoNothingVisitor

org.lsmp.djep.xjep.SubstitutionVisitor

All Implemented Interfaces:

ParserVisitor

public class SubstitutionVisitor
extends DoNothingVisitor

Allows substitution of a given variable with an expression tree. Substitution is best done using the XJep.substitute method. For example

 XJepI xjep = ...;
 Node node = xjep.parse("x^2+x");
 Node sub = xjep.parse("sin(y)");
 Node res = xjep.substitute(node,"x",sub,xjep);
 

Will give the expression "(sin(y))^2+sin(y)".

Author:

Rich Morris Created on 16-Nov-2003

Constructor Summary

Constructors

Constructor and Description
SubstitutionVisitor()

Method Summary

Modifier and Type	Method and Description
Node	substitute(Node orig, String[] names, Node[] replacements, XJep xj) Substitutes all occurrences of a set of variable var with a set of replacements.
Node	substitute(Node orig, String name, Node replacement, XJep xj) Substitutes all occurrences of variable var with replacement.
Object	visit(ASTVarNode node, Object data)

Methods inherited from class org.lsmp.djep.xjep.DoNothingVisitor

acceptChildrenAsArray, visit, visit, visit, visit

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SubstitutionVisitor

public SubstitutionVisitor()

Method Detail

substitute

public Node substitute(Node orig,
                       String name,
                       Node replacement,
                       XJep xj)
                throws ParseException

Substitutes all occurrences of variable var with replacement. Does not do a DeepCopy.

Parameters:

orig - the expression we wish to perform the substitution on

name - the name of the variable

replacement - the expression var is substituted for

Returns:

the tree with variable replace (does not do a DeepCopy)

Throws:

ParseException

substitute

public Node substitute(Node orig,
                       String[] names,
                       Node[] replacements,
                       XJep xj)
                throws ParseException

Substitutes all occurrences of a set of variable var with a set of replacements. Does not do a DeepCopy.

Parameters:

orig - the expression we wish to perform the substitution on

names - the names of the variable

replacements - the expression var is substituted for

Returns:

the tree with variable replace (does not do a DeepCopy)

Throws:

ParseException

visit

public Object visit(ASTVarNode node,
                    Object data)
             throws ParseException

Specified by:

visit in interface ParserVisitor

Overrides:

visit in class DoNothingVisitor

Throws:

ParseException