org.lsmp.djep.xjep.PrintVisitor Maven / Gradle / Ivy
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JEP is a Java library for parsing and evaluating mathematical expressions.
The newest version!
/* @author rich
* Created on 18-Jun-2003
*/
package org.lsmp.djep.xjep;
import org.nfunk.jep.*;
import org.nfunk.jep.type.*;
import java.io.PrintStream;
import java.util.Hashtable;
import java.text.NumberFormat;
import java.text.FieldPosition;
/**
* Prints an expression.
* Prints the expression with lots of brackets.
* ((-1.0)/sqrt((1.0-(x^2.0)))).
* To use
*
* XJep j = ...; Node in = ...;
* j.print(in,"x");
*
* @author Rich Morris
* Created on 20-Jun-2003
* @since Dec 04 and NumberFormat object can be supplied to modify printing of numbers.
* @since 21 Dec 04 PrintVisitor can now cope with 3 or more arguments to + and *.
* @see XJep#print(Node)
* @see XJep#print(Node, PrintStream)
* @see XJep#println(Node)
* @see XJep#println(Node, PrintStream)
* @see XJep#toString(Node)
*/
public class PrintVisitor extends ErrorCatchingVisitor
{
/** All brackets are printed. Removes all ambiguity. */
public static final int FULL_BRACKET = 1;
/** Print Complex as 3+2 i */
public static final int COMPLEX_I = 2;
private int maxLen = -1;
protected StringBuffer sb;
/** The current mode for printing. */
// protected boolean fullBrackets=false;
protected int mode=0;
private Hashtable specialRules = new Hashtable();
/** Creates a visitor to create and print string representations of an expression tree. **/
public PrintVisitor()
{
}
/** Prints the tree descending from node with lots of brackets
* or specified stream.
* @see XJep#println(Node, PrintStream)
**/
public void print(Node node,PrintStream out)
{
sb = new StringBuffer();
acceptCatchingErrors(node,null);
if(maxLen == -1)
out.print(sb);
else
{
while(true) {
if(sb.length() < maxLen) {
out.print(sb);
return;
}
int pos = maxLen-2;
for(int i=maxLen-2;i>=0;--i) {
char c = sb.charAt(i);
if(c == '+' || c == '-' || c == '*' || c == '/'){
pos = i; break;
}
}
//out.println("<"+sb.substring(0,pos+10)+">");
out.println(sb.substring(0,pos+1));
sb.delete(0,pos+1);
}
}
}
/** Prints on System.out. */
public void print(Node node) { print(node,System.out); }
/** Prints the tree descending from node with a newline at end. **/
public void println(Node node,PrintStream out)
{
print(node,out);
out.println("");
}
/** Prints on System.out. */
public void println(Node node) { println(node,System.out); }
/** returns a String representation of the equation. */
public String toString(Node node)
{
sb = new StringBuffer();
acceptCatchingErrors(node,null);
return sb.toString();
}
/**
* This interface specifies the method needed to implement a special print rule.
* A special rule must implement the append method, which should
* call pv.append to add data to the output. For example
*
* pv.addSpecialRule(Operator.OP_LIST,new PrintVisitor.PrintRulesI()
* {
* public void append(Node node,PrintVisitor pv) throws ParseException
* {
* pv.append("[");
* for(int i=0;i0) pv.append(",");
* node.jjtGetChild(i).jjtAccept(pv, null);
* }
* pv.append("]");
* }});
*
* @author Rich Morris
* Created on 21-Feb-2004
*/
public interface PrintRulesI
{
/** The method called to append data for the rule. **/
public void append(Node node,PrintVisitor pv) throws ParseException;
}
/** Add a string to buffer. Classes implementing PrintRulesI
* should call this add the */
public void append(String s) { sb.append(s); }
/** Adds a special print rule to be added for a given operator.
* TODO Allow special rules for other functions, i.e. not operators. */
public void addSpecialRule(Operator op,PrintRulesI rules)
{
specialRules.put(op,rules);
}
/***************** visitor methods ********************************/
/** print the node with no brackets. */
private void printNoBrackets(Node node) throws ParseException
{
node.jjtAccept(this,null);
}
/** print a node surrounded by brackets. */
private void printBrackets(Node node) throws ParseException
{
sb.append("(");
printNoBrackets(node);
sb.append(")");
}
/** print a unary operator. */
private Object visitUnary(ASTFunNode node, Object data) throws ParseException
{
Node rhs = node.jjtGetChild(0);
// now print the node
sb.append(node.getOperator().getSymbol());
// now the rhs
if(rhs instanceof ASTFunNode && ((ASTFunNode) rhs).isOperator())
printBrackets(rhs); // -(-3) -(1+2) or !(-3)
else
printNoBrackets(rhs);
return data;
}
private boolean testLeft(XOperator top,Node lhs)
{
if((mode & FULL_BRACKET)!= 0)
{
return true;
}
else if(lhs instanceof ASTFunNode && ((ASTFunNode) lhs).isOperator())
{
XOperator lhsop = (XOperator) ((ASTFunNode) lhs).getOperator();
if(top == lhsop)
{
if(top.getBinding() == XOperator.LEFT // (1-2)-3 -> 1-2-3
&& top.isAssociative() )
return false;
else if(top.useBindingForPrint())
return false;
else
return true; // (1=2)=3 -> (1=2)=3
}
else if(top.getPrecedence() == lhsop.getPrecedence())
{
if(lhsop.getBinding() == XOperator.LEFT && lhsop.isAssociative())
return false;
else if(lhsop.useBindingForPrint())
return false;
else return true;
} // (1=2)=3 -> (1=2)=3
else if(top.getPrecedence() > lhsop.getPrecedence()) // (1*2)+3
return false;
else
return true;
}
else
return false;
}
private boolean testMid(XOperator top,Node rhs)
{
if((mode & FULL_BRACKET)!= 0)
{
return true;
}
else if(rhs instanceof ASTFunNode && ((ASTFunNode) rhs).isOperator())
{
XOperator rhsop = (XOperator) ((ASTFunNode) rhs).getOperator();
if(top == rhsop)
{
return false;
}
else if(top.getPrecedence() == rhsop.getPrecedence())
{
return false; // a+(b-c) -> a+b-c
}
else if(top.getPrecedence() > rhsop.getPrecedence()) // 1+(2*3) -> 1+2*3
return false;
else
return true;
}
else
return false;
}
private boolean testRight(XOperator top,Node rhs)
{
if((mode & FULL_BRACKET)!= 0)
{
return true;
}
else if(rhs instanceof ASTFunNode && ((ASTFunNode) rhs).isOperator())
{
XOperator rhsop = (XOperator) ((ASTFunNode) rhs).getOperator();
if(top == rhsop)
{
if(top.getBinding() == XOperator.RIGHT // 1=(2=3) -> 1=2=3
|| top.isAssociative() ) // 1+(2-3) -> 1+2-3
return false;
return true; // 1-(2+3) -> 1-(2-3)
}
else if(top.getPrecedence() == rhsop.getPrecedence())
{
if(top.getBinding() == XOperator.LEFT && top.isAssociative() ) // 1+(2-3) -> 1+2-3)
return false; // a+(b-c) -> a+b-c
return true; // a-(b+c) -> a-(b+c)
}
else if(top.getPrecedence() > rhsop.getPrecedence()) // 1+(2*3) -> 1+2*3
return false;
else
return true;
}
else
return false;
}
private Object visitNaryBinary(ASTFunNode node,XOperator op) throws ParseException
{
int n = node.jjtGetNumChildren();
for(int i=0;i0) sb.append(op.getSymbol());
Node arg = node.jjtGetChild(i);
if(testMid(op,arg))
printBrackets(arg);
else
printNoBrackets(arg);
}
return null;
}
public Object visit(ASTFunNode node, Object data) throws ParseException
{
if(!node.isOperator()) return visitFun(node);
if(node instanceof PrintRulesI)
{
((PrintRulesI) node).append(node,this);
return null;
}
if(node.getOperator()==null)
{
throw new ParseException("Null operator in print for "+node);
}
if(specialRules.containsKey(node.getOperator()))
{
((PrintRulesI) specialRules.get(node.getOperator())).append(node,this);
return null;
}
if(node.getPFMC() instanceof org.nfunk.jep.function.List)
{
append("[");
for(int i=0;i0) append(",");
node.jjtGetChild(i).jjtAccept(this, null);
}
append("]");
return null;
}
if(((XOperator) node.getOperator()).isUnary())
return visitUnary(node,data);
if(((XOperator) node.getOperator()).isBinary())
{
XOperator top = (XOperator) node.getOperator();
if(node.jjtGetNumChildren()!=2)
return visitNaryBinary(node,top);
Node lhs = node.jjtGetChild(0);
Node rhs = node.jjtGetChild(1);
if(testLeft(top,lhs))
printBrackets(lhs);
else
printNoBrackets(lhs);
// now print the node
sb.append(node.getOperator().getSymbol());
// now the rhs
if(testRight(top,rhs))
printBrackets(rhs);
else
printNoBrackets(rhs);
}
return null;
}
/** prints a standard function: fun(arg,arg) */
private Object visitFun(ASTFunNode node) throws ParseException
{
sb.append(node.getName()+"(");
for(int i=0;i0) sb.append(",");
node.jjtGetChild(i).jjtAccept(this, null);
}
sb.append(")");
return null;
}
public Object visit(ASTVarNode node, Object data) throws ParseException {
sb.append(node.getName());
return data;
}
public Object visit(ASTConstant node, Object data) {
Object val = node.getValue();
formatValue(val,sb);
return data;
}
private FieldPosition fp = new FieldPosition(NumberFormat.FRACTION_FIELD);
/** Appends a formatted versions of val to the string buffer.
*
* @param val The value to format
* @param sb1 The StingBuffer to append to
*/
public void formatValue(Object val,StringBuffer sb1)
{
if(format != null)
{
if(val instanceof Number)
format.format(val,sb1,fp);
else if(val instanceof Complex)
{
if((mode | COMPLEX_I) == COMPLEX_I)
sb1.append(((Complex) val).toString(format,true));
else
sb1.append(((Complex) val).toString(format));
}
else
sb1.append(val);
}
else
sb1.append(val);
}
/** Returns a formated version of the value. */
public String formatValue(Object val)
{
StringBuffer sb2 = new StringBuffer();
formatValue(val,sb2);
return sb2.toString();
}
/**
* Return the current print mode.
*/
public int getMode() {
return mode;
}
public boolean getMode(int testmode) {
return( (this.mode | testmode ) == testmode);
}
/**
* Set printing mode.
* In full bracket mode the brackets each element in the tree will be surrounded
* by brackets to indicate the tree structure.
* In the default mode, (full bracket off) the number of brackets is
* minimised so (x+y)+z will be printed as x+y+z.
* @param mode which flags to change, typically FULL_BRACKET
* @param flag whether to switch this mode on or off
*/
public void setMode(int mode,boolean flag) {
if(flag)
this.mode |= mode;
else
this.mode ^= mode;
}
/** The NumberFormat object used to print numbers. */
protected NumberFormat format;
public void setNumberFormat(NumberFormat format)
{
this.format = format;
}
/**
* Sets the maximum length printed per line.
* If the value is not -1 then the string will be broken into chunks
* each of which is less than the max length.
* @param i the maximum length
*/
public void setMaxLen(int i) {
maxLen = i;
}
/**
* @return the maximum length printed per line
*/
public int getMaxLen() {
return maxLen;
}
}
/*end*/