Class expression.Expression 
All Packages  Class Hierarchy  This Package  Previous  Next  Index

Class expression.Expression 

java.lang.Object
   |
   +----expression.Expression
public class Expression
extends Object
The class representing an expression. Legal expression symbols include: all double precision numbers; arithmetic operators including '+', '-', '*', '/' and '^'; left bracket '(' and right bracket ')'; Three variables including 'x' (or 'X'), 'y' (or 'Y') and 'z' (or 'Z'); And many unary functions such as 'COS', 'SIN', etc.

Variable Index

o enode
The root expression node generated by parsing the expression string.
o symQueue
The symbol queue created for operator-precedence parsing.
o symStack
The operator, expression node stack created for operator-precedence parsing.

Constructor Index

o Expression()
Construct an empty expression.
o Expression(String)
Construct an expression by a string representation.

Method Index

o appendSymbol(Symbol)
Append a symbol to the end of an expression.
o eval()
Evaluate the expression.
o getErrMsg()
Return a string indicates where the parsing error occurs.
o nextSymbol(StreamTokenizer)
Fetch the next symbol from the input expression string.
o toSymbol(String)
Convert a string to a symbol.

Variables

o enode 
  public ExprNode enode
The root expression node generated by parsing the expression string.
o symQueue 
  public Vector symQueue
The symbol queue created for operator-precedence parsing.
o symStack 
  public Stack symStack
The operator, expression node stack created for operator-precedence parsing.

Constructors

o Expression 
  public Expression()
Construct an empty expression.
o Expression 
  public Expression(String expr) throws ExpressionParseException
Construct an expression by a string representation.

Methods

o appendSymbol 
  public boolean appendSymbol(Symbol sym) throws ExpressionParseException
Append a symbol to the end of an expression. Return true if the whole expression is reduced into a single expression node, or the expression is empty.
o eval 
  public double eval() throws ExpressionEvalException
Evaluate the expression.
o toSymbol 
  public static Symbol toSymbol(String s)
Convert a string to a symbol.
o nextSymbol 
  public static Symbol nextSymbol(StreamTokenizer st) throws IOException, ExpressionParseException
Fetch the next symbol from the input expression string.
o getErrMsg 
  public String getErrMsg()
Return a string indicates where the parsing error occurs. 
All Packages  Class Hierarchy  This Package  Previous  Next  Index