com.singularsys.jep.walkers
Class SubstitutionVisitor

java.lang.Object
  com.singularsys.jep.walkers.DoNothingVisitor
      com.singularsys.jep.walkers.SubstitutionVisitor

All Implemented Interfaces:

ParserVisitor

public class SubstitutionVisitor
extends DoNothingVisitor

Allows substitution of a given variable with an expression tree. For example

 Jep jep = new Jep();
 Node node = jep.parse("x^2+x");
 SubstitutionVisitor sv = new SubstitutionVisitor(jep);
 Node sub = jep.parse("sin(y)");
 Node res = sv.substitute(node,"x",sub);
 

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

Author:

Rich Morris Created on 16-Nov-2003

Field Summary

protected Operator	assign
protected DeepCopyVisitor	dcv

Fields inherited from class com.singularsys.jep.walkers.DoNothingVisitor

ft, jep, nf, ot, vt

Constructor Summary

SubstitutionVisitor(Jep j)

Method Summary

Node	substitute(Node orig, Node sub) Substitutes into orig the equation given by sub
Node	substitute(Node orig, Node[] subs)
Node	substitute(Node orig, java.lang.String[] names, Node[] replacements) Substitutes all occurrences of a set of variable var with a set of replacements.
Node	substitute(Node orig, java.lang.String[] names, java.lang.Object[] values) Substitute a set of names with a set of values.
Node	substitute(Node orig, java.lang.String name, Node replacement) Substitutes all occurrences of variable var with replacement.
java.lang.Object	visit(ASTVarNode node, java.lang.Object data) Visit a variable node.

Methods inherited from class com.singularsys.jep.walkers.DoNothingVisitor

copyChildrenIfNeeded, visit, visit, visit, visit, visitChildren, visitNode

Methods inherited from class java.lang.Object

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

Field Detail

assign

protected Operator assign

dcv

protected DeepCopyVisitor dcv

Constructor Detail

SubstitutionVisitor

public SubstitutionVisitor(Jep j)

Method Detail

substitute

public Node substitute(Node orig,
                       java.lang.String name,
                       Node replacement)
                throws JepException

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:

JepException

substitute

public Node substitute(Node orig,
                       Node sub)
                throws JepException

Substitutes into orig the equation given by sub

Parameters:

orig - the equation to substitute into

sub - and equation of the form x=....

Returns:

orig after substitution

Throws:

JepException - if sub is of the wrong form

substitute

public Node substitute(Node orig,
                       Node[] subs)
                throws JepException

Throws:

JepException

substitute

public Node substitute(Node orig,
                       java.lang.String[] names,
                       Node[] replacements)
                throws JepException

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:

JepException

substitute

public Node substitute(Node orig,
                       java.lang.String[] names,
                       java.lang.Object[] values)
                throws JepException

Substitute a set of names with a set of values.

Parameters:

orig -

names -

values -

Returns:

node with the substitution performed

Throws:

JepException

visit

public java.lang.Object visit(ASTVarNode node,
                              java.lang.Object data)
                       throws JepException

Description copied from class: DoNothingVisitor

Visit a variable node. Can be overridden buy sub-classes.

Specified by:

visit in interface ParserVisitor

Overrides:

visit in class DoNothingVisitor

Throws:

JepException