org.scijava.parsington

Class Group

java.lang.Object

org.scijava.parsington.Token

org.scijava.parsington.Operator

org.scijava.parsington.Group

All Implemented Interfaces:

Comparable<Operator>

public class Group
extends Operator

A group is a special N-ary operator delineated by a left-hand symbol and a right-hand symbol, with comma-separated arguments.

Typically, these are various forms of parentheses, although in principle any pair of two distinct symbols is allowed.

Author:

Curtis Rueden

Nested Class Summary

Nested classes/interfaces inherited from class org.scijava.parsington.Operator

Operator.Associativity

Constructor Summary

Constructors

Constructor and Description
Group(String initiator, String terminator, double precedence) Creates a new group.

Method Summary

Modifier and Type	Method and Description
int	getArity() Gets the operator's arity.
String	getTerminator() Gets the group's terminator symbol.
void	incArity() Increments the group's arity.
Group	instance() Creates an instance of a group operator, using this one as a template.
boolean	isInfix() Gets whether the operator is an infix operator (e.g., a-b).
boolean	isPrefix() Gets whether the operator is a prefix operator (e.g., -a).
boolean	matches(Group g) Gets whether the given group is the same as this one, in terms of token (lefthand symbol), terminator (righthand symbol) and precedence.
String	toString()

Methods inherited from class org.scijava.parsington.Operator

compareTo, getAssociativity, getPrecedence, isLeftAssociative, isPostfix, isRightAssociative

Methods inherited from class org.scijava.parsington.Token

getToken

Methods inherited from class java.lang.Object

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

Constructor Detail

Group

public Group(String initiator,
             String terminator,
             double precedence)

Creates a new group.

Parameters:

initiator - The lefthand symbol signaling the start of the group.

terminator - The righthand symbol signaling the end of the group.

precedence - The group's operator precedence.

Method Detail

getTerminator

public String getTerminator()

Gets the group's terminator symbol. (Use Token.getToken() to obtain the initiator symbol.)

Returns:

The terminator symbol.

incArity

public void incArity()

Increments the group's arity.

matches

public boolean matches(Group g)

Gets whether the given group is the same as this one, in terms of token (lefthand symbol), terminator (righthand symbol) and precedence.

Note that this method intentionally does not compare arity; the idea is that if you have a Group and call instance() to duplicate it, that copy will match this one, even though the copy initially starts at arity 0.

Parameters:

g - The group to compare with this one.

Returns:

True iff the given group is the same as this one, in terms of token, terminator, and precedence.

getArity

public int getArity()

Description copied from class: Operator

Gets the operator's arity.

Overrides:

getArity in class Operator

Returns:

The arity of the operator: 1 for unary, 2 for binary, etc.

isInfix

public boolean isInfix()

Description copied from class: Operator

Gets whether the operator is an infix operator (e.g., a-b).

Overrides:

isInfix in class Operator

Returns:

True iff the operator is an infix operator.

isPrefix

public boolean isPrefix()

Description copied from class: Operator

Gets whether the operator is a prefix operator (e.g., -a).

Overrides:

isPrefix in class Operator

Returns:

True iff the operator is a prefix operator.

instance

public Group instance()

Creates an instance of a group operator, using this one as a template.

The created group will have the same initiator and terminator symbols, as well as the same precedence. But it will begin as a nullary group until incArity() is called.

Overrides:

instance in class Operator

Returns:

this or a new instance, depending on the type of operator.

toString

public String toString()

Overrides:

toString in class Token