com.singularsys.jep
Class Operator

java.lang.Object
  com.singularsys.jep.Operator

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

TernaryOperator, TernaryOperator.RhsTernaryOperator

public class Operator
extends java.lang.Object
implements java.io.Serializable

An Operator with additional information about its commutativity etc.

Operators have a number of properties:

• A symbol or name of the operator "+".
• The number of arguments NO_ARGS 0, UNARY 1 (e.g. UMINUS -x), BINARY 2 (e.g. x+y), and NARY either 3 ( a>b ? a : b) or unspecified like a list [x,y,z,w].
• The binding of the operator, LEFT 1+2+3 -> (1+2)+3 or RIGHT 1=2=3 -> 1=(2=3).
• Whether the operator is ASSOCIATIVE or COMMUTATIVE.
• The precedence of the operators + has a higher precedence than *.
• For unary operators they can either be PREFIX like -x or SUFFIX like x%.
• Comparative operators can be REFLEXIVE, SYMMETRIC, TRANSITIVE or EQUIVALENCE which has all three properties.
• A reference to a PostfixtMathCommandI object which is used to evaluate an equation containing the operator.

Various is... and get... methods are provided to query the properties of the operator.

Author:

Rich Morris Created on 19-Oct-2003

See Also:

Serialized Form

Field Summary

static int	ASSOCIATIVE Associative operators x*(y*z) == (x*y)*z .
static int	BINARY Binary operators, such as x+y, x>y
static int	COMMUTATIVE Commutative operators x*y = y*x.
static int	COMPOSITE composite operators, like a-b which is a+(-b)
static int	EQUIVALENCE Equivalence relations = reflexive, transitive and symmetric.
static int	LEFT Left binding like +: 1+2+3 -> (1+2)+3
static int	NARY Trinary ops such as ?
static int	NO_ARGS No arguments to operator
static int	NOT_IN_PARSER Non standard operators, like array access.
static int	PREFIX prefix operators -x
static int	REFLEXIVE Reflective relations x=x for all x.
static int	RIGHT Right binding like =: 1=2=3 -> 1=(2=3)
static int	SELF_INVERSE self inverse operators like -(-x) !
static int	SUFFIX postfix operators x%
static int	SYMMETRIC Symmetric relation x=y implies y=x.
static int	TERNARY three argument operators like java's cond?
static int	TRANSITIVE Transitive relations x=y and y=z implies x=z
static int	UNARY Unary operators, such as -x !
static int	USE_BINDING_FOR_PRINT For non commutative operators printing can be determined by the left or right binding.

Constructor Summary

Operator(java.lang.String name, PostfixMathCommandI pfmc, int flags)
Construct a new operator with no precedence set.

Operator(java.lang.String name, PostfixMathCommandI pfmc, int flags, int precedence)
Constructs a new operator with a given precedence.

Operator(java.lang.String name, java.lang.String symbol, PostfixMathCommandI pfmc, int flags)
Constructs a new operator, with a different name and symbol

Operator(java.lang.String name, java.lang.String symbol, PostfixMathCommandI pfmc, int flags, int precedence)
Constructs a new operator, with a different name and symbol and allows a given precedence to be set.

Method Summary

boolean	addAltSymbol(java.lang.String altSymbol) Adds an alternate symbol which can be used at parse time.
java.util.List<java.lang.String>	getAltSymbols()
Operator	getBinaryInverseOp()
int	getBinding() Deprecated.
int	getFlags()
Operator	getInverseOp()
int	getKey() Get the key code used to identify the operator in the operator table.
java.lang.String	getName() returns a unique name defining this operator.
PostfixMathCommandI	getPFMC()
int	getPrecedence() Get the precedence of the operator.
Operator	getRootOp()
java.lang.String	getSymbol() returns the symbol used by this operator.
boolean	isAssociative()
boolean	isBinary()
boolean	isCommutative()
boolean	isComposite()
boolean	isDistributiveOver(Operator op)
boolean	isEquivalence()
boolean	isLeftBinding()
boolean	isNary()
boolean	isPrefix()
boolean	isReflexive()
boolean	isRightBinding()
boolean	isSelfInverse()
boolean	isSuffix()
boolean	isSymmetric()
boolean	isTernary()
boolean	isTransitive()
boolean	isUnary()
boolean	notInParser()
int	numArgs()
void	setBinaryInverseOp(Operator inv)
void	setDistributiveOver(Operator op)
void	setFlag(int flag, boolean val) Set the value of a specific flag.
void	setInverseOp(Operator inv)
void	setKey(int key) Key code used to identify the operator in the operator table.
void	setPFMC(PostfixMathCommandI pfmc)
void	setPrecedence(int i) Set the precedence of the operator.
void	setRootOp(Operator root)
void	setSymbol(java.lang.String sym) Sets the symbol used by the operator.
java.lang.String	toFullString() returns a verbose representation of the operator and all its properties.
java.lang.String	toString()
boolean	useBindingForPrint()

Methods inherited from class java.lang.Object

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

Field Detail

NO_ARGS

public static final int NO_ARGS

No arguments to operator

See Also:

Constant Field Values

UNARY

public static final int UNARY

Unary operators, such as -x !x ~x

See Also:

Constant Field Values

BINARY

public static final int BINARY

Binary operators, such as x+y, x>y

See Also:

Constant Field Values

NARY

public static final int NARY

Trinary ops such as ?: and or higher like [x,y,z,w]

See Also:

Constant Field Values

LEFT

public static final int LEFT

Left binding like +: 1+2+3 -> (1+2)+3

See Also:

Constant Field Values

RIGHT

public static final int RIGHT

Right binding like =: 1=2=3 -> 1=(2=3)

See Also:

Constant Field Values

ASSOCIATIVE

public static final int ASSOCIATIVE

Associative operators x*(y*z) == (x*y)*z .

See Also:

Constant Field Values

COMMUTATIVE

public static final int COMMUTATIVE

Commutative operators x*y = y*x.

See Also:

Constant Field Values

REFLEXIVE

public static final int REFLEXIVE

Reflective relations x=x for all x.

See Also:

Constant Field Values

SYMMETRIC

public static final int SYMMETRIC

Symmetric relation x=y implies y=x.

See Also:

Constant Field Values

TRANSITIVE

public static final int TRANSITIVE

Transitive relations x=y and y=z implies x=z

See Also:

Constant Field Values

EQUIVALENCE

public static final int EQUIVALENCE

Equivalence relations = reflexive, transitive and symmetric.

See Also:

Constant Field Values

PREFIX

public static final int PREFIX

prefix operators -x

See Also:

Constant Field Values

SUFFIX

public static final int SUFFIX

postfix operators x%

See Also:

Constant Field Values

SELF_INVERSE

public static final int SELF_INVERSE

self inverse operators like -(-x) !(!x)

See Also:

Constant Field Values

COMPOSITE

public static final int COMPOSITE

composite operators, like a-b which is a+(-b)

See Also:

Constant Field Values

USE_BINDING_FOR_PRINT

public static final int USE_BINDING_FOR_PRINT

For non commutative operators printing can be determined by the left or right binding. For example (a-b)-c is printed as a-b-c (flag set). But a/b/c could be ambiguous so (a/b)/c is printed with brackets (flag not set).

See Also:

Constant Field Values

NOT_IN_PARSER

public static final int NOT_IN_PARSER

Non standard operators, like array access. These will typically require the PrintRulesI interface to print and require special parsing options.

See Also:

Constant Field Values

TERNARY

public static final int TERNARY

three argument operators like java's cond?tval:fval

See Also:

TernaryOperator, Constant Field Values

Constructor Detail

Operator

public Operator(java.lang.String name,
                PostfixMathCommandI pfmc,
                int flags)

Construct a new operator with no precedence set.

Parameters:

name - printable name of the operator

pfmc - postfix math command for the operator

flags - set of flags defining the properties of the operator.

Operator

public Operator(java.lang.String name,
                PostfixMathCommandI pfmc,
                int flags,
                int precedence)

Constructs a new operator with a given precedence.

Parameters:

name - printable name of the operator

pfmc - postfix math command for the operator

flags - set of flags defining the properties of the operator

precedence - operator precedence to be set

Operator

public Operator(java.lang.String name,
                java.lang.String symbol,
                PostfixMathCommandI pfmc,
                int flags)

Constructs a new operator, with a different name and symbol

Parameters:

name - name of operator, must be unique, used when describing operator

symbol - printable name of operator, used for printing equations

pfmc - postfix math command for operator

flags - set of flags defining the properties of the operator

Operator

public Operator(java.lang.String name,
                java.lang.String symbol,
                PostfixMathCommandI pfmc,
                int flags,
                int precedence)

Constructs a new operator, with a different name and symbol and allows a given precedence to be set.

Parameters:

name - name of operator, must be unique, used when describing operator

symbol - printable name of operator, used for printing equations

pfmc - postfix math command for operator

flags - set of flags defining the properties of the operator.

precedence - operator precedence to be set

Method Detail

getSymbol

public final java.lang.String getSymbol()

returns the symbol used by this operator.

setSymbol

public final void setSymbol(java.lang.String sym)

Sets the symbol used by the operator. Note Jep.reinitializeComponents() must be called after using this method.

Parameters:

sym - the new symbol to use.

getName

public final java.lang.String getName()

returns a unique name defining this operator.

getPFMC

public final PostfixMathCommandI getPFMC()

setPFMC

public final void setPFMC(PostfixMathCommandI pfmc)

getPrecedence

public final int getPrecedence()

Get the precedence of the operator. Lower values correspond to tighter binding, that is * gives a lower value than + and 1+2*3 is 1+(2*3).

Returns:

the precedence

setPrecedence

public void setPrecedence(int i)

Set the precedence of the operator. Lower values correspond to tighter binding, that is * gives a lower value than + and 1+2*3 is 1+(2*3).

setDistributiveOver

public final void setDistributiveOver(Operator op)

isDistributiveOver

public boolean isDistributiveOver(Operator op)

setRootOp

public void setRootOp(Operator root)

setInverseOp

public void setInverseOp(Operator inv)

setBinaryInverseOp

public void setBinaryInverseOp(Operator inv)

getRootOp

public Operator getRootOp()

getInverseOp

public Operator getInverseOp()

getBinaryInverseOp

public Operator getBinaryInverseOp()

getFlags

public final int getFlags()

getBinding

@Deprecated
public final int getBinding()

Deprecated.

When parsing how is x+y+z interpreted. Can be Operator.LEFT x+y+z -> (x+y)+z or Operator.RIGHT x=y=z -> x=(y=z). This is now deprecated

See Also:

isLeftBinding(), isRightBinding()

isLeftBinding

public final boolean isLeftBinding()

isRightBinding

public final boolean isRightBinding()

isAssociative

public final boolean isAssociative()

isCommutative

public final boolean isCommutative()

isBinary

public final boolean isBinary()

isUnary

public final boolean isUnary()

isNary

public final boolean isNary()

numArgs

public final int numArgs()

isTransitive

public final boolean isTransitive()

isSymmetric

public final boolean isSymmetric()

isReflexive

public final boolean isReflexive()

isEquivalence

public final boolean isEquivalence()

isPrefix

public final boolean isPrefix()

isSuffix

public final boolean isSuffix()

isTernary

public final boolean isTernary()

isComposite

public final boolean isComposite()

isSelfInverse

public final boolean isSelfInverse()

useBindingForPrint

public final boolean useBindingForPrint()

notInParser

public final boolean notInParser()

setFlag

public void setFlag(int flag,
                    boolean val)

Set the value of a specific flag. Use with care

Parameters:

flag -

val -

toFullString

public java.lang.String toFullString()

returns a verbose representation of the operator and all its properties.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getKey

public int getKey()

Get the key code used to identify the operator in the operator table.

setKey

public void setKey(int key)

Key code used to identify the operator in the operator table.

getAltSymbols

public java.util.List<java.lang.String> getAltSymbols()

addAltSymbol

public boolean addAltSymbol(java.lang.String altSymbol)

Adds an alternate symbol which can be used at parse time. The alternate symbol added will be recognised at parse time by configurable parser the normal symbol will be used in output. For example unicode U+002D the hyphen minus (-), U+2212 the unicode minus symbol (−), U+2013 then en-dash (–) may appear in some input to represent minus. Other alternate characters include U+2264 less-than or equals (≤), U+2264 greater-than or equals (≥), U+2215 unicode division symbol (∕), U+00D7 multiplication (×).

Parameters:

altSymbol -

Returns:

true