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Class expression.Symbol

java.lang.Object
   |
   +----expression.Symbol

public class Symbol

extends Object

SYM_EXPRNODE

The symbol type representing a reduced expression node.

SYM_TERMINAL

The symbol type representing a terminal symbol.

SYM_UNKNOWN

The symbol type representing unknown symbol.

TK_BRACKETL

The token representing a left bracket in an expression.

TK_BRACKETR

The token representing a right bracket in an expression.

TK_DIV

The token representing a division sign in an expression.

TK_EOE

The token representing the end of an expression.

TK_FUNCTION

The token representing a function in an expression.

TK_MINUS

The token representing a minus sign in an expression.

TK_MULT

The token representing a multply sign in an expression.

TK_NUMBER

The token representing a number in an expression.

TK_PLUS

The token representing a plus sign in an expression.

TK_POW

The token representing a power sign in an expression.

TK_VARIABLE

The token representing a variable in an expression.

enode

The reduced expression node, if symbol type if SYM_EXPRNODE.

func

The function of a TK_FUNCTION token.

nval

The value of a TK_NUMBER token.

stype

Symbol type of the symbol.

ttype

The terminal type of the symbol, if symbol type if SYM_TERMINAL.

variable

The variable of a TK_VARIABLE token.

Symbol()

Create an empty symbol.

Symbol(int, int)

Create a token symbol with symbol type and token type.

Symbol(int, int, double)

Create a Number token with symbol type specified as SYM_TERMINAL, token type specified as TK_NUMBER and a value

Symbol(int, int, char)

Symbol(int, int, String)

Create a Variable token or Function token with symbol type specified as SYM_TERMINAL.

Symbol(int, ExprNode)

Create a Function token with symbol type specified as SYM_EXPRNODE, and an expression node.

equal(Symbol)

Returns true if current symbol has the same precedence as symbol a.

greater(Symbol)

Returns true if current symbol has higher precedence than symbol a.

isEOE()

Returns true if the symbol represents the end of an expression.

isExprNode()

Returns true if the symbol represents an expression node.

less(Symbol)

Returns true if current symbol has lower precedence than symbol a.

toString()

Returns the string representation of the current symbol.

  public final static int SYM_UNKNOWN

The symbol type representing unknown symbol.

  public final static int SYM_EXPRNODE

The symbol type representing a reduced expression node.

  public final static int SYM_TERMINAL

The symbol type representing a terminal symbol.

  public final static int TK_EOE

The token representing the end of an expression.

  public final static int TK_NUMBER

The token representing a number in an expression.

  public final static int TK_VARIABLE

The token representing a variable in an expression.

  public final static int TK_BRACKETL

The token representing a left bracket in an expression.

  public final static int TK_BRACKETR

The token representing a right bracket in an expression.

  public final static int TK_PLUS

The token representing a plus sign in an expression.

  public final static int TK_MINUS

The token representing a minus sign in an expression.

  public final static int TK_MULT

The token representing a multply sign in an expression.

  public final static int TK_DIV

The token representing a division sign in an expression.

  public final static int TK_POW

The token representing a power sign in an expression.

  public final static int TK_FUNCTION

The token representing a function in an expression.

  public int stype

Symbol type of the symbol.

  public int ttype

The terminal type of the symbol, if symbol type if SYM_TERMINAL.

  public ExprNode enode

The reduced expression node, if symbol type if SYM_EXPRNODE.

  public double nval

The value of a TK_NUMBER token.

  public Function func

The function of a TK_FUNCTION token.

  public Variable variable

The variable of a TK_VARIABLE token.

  public Symbol()

Create an empty symbol.

  public Symbol(int type,
                int tk)

Create a token symbol with symbol type and token type. It is used for creating symbols for operators, EOE and brackets.

  public Symbol(int type,
                int tk,
                double val)

Create a Number token with symbol type specified as SYM_TERMINAL, token type specified as TK_NUMBER and a value

  public Symbol(int type,
                int tk,
                char vchar) throws ExpressionParseException

  public Symbol(int type,
                int tk,
                String str) throws ExpressionParseException

Create a Variable token or Function token with symbol type specified as SYM_TERMINAL. Variable token will be created if token type is specified as TK_VARIABLE and the string representation of a variable ("X", "Y", "Z", "E", "PI") is given. Function token will be created if token type is specified as TK_FUNCTION and the string representation of the function is given.

  public Symbol(int type,
                ExprNode en)

Create a Function token with symbol type specified as SYM_EXPRNODE, and an expression node.

  public boolean isEOE()

Returns true if the symbol represents the end of an expression.

  public boolean isExprNode()

Returns true if the symbol represents an expression node.

  public boolean less(Symbol a) throws ExpressionParseException

Returns true if current symbol has lower precedence than symbol a.

  public boolean equal(Symbol a) throws ExpressionParseException

Returns true if current symbol has the same precedence as symbol a.

  public boolean greater(Symbol a) throws ExpressionParseException

Returns true if current symbol has higher precedence than symbol a.

  public String toString()

Returns the string representation of the current symbol.

Overrides:

toString in class Object

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