org.scijava.parsington

Class ParseOperation

java.lang.Object

org.scijava.parsington.ParseOperation

public class ParseOperation
extends Object

A stateful parsing operation.

Field Summary

Fields

Modifier and Type	Field and Description
protected String	expression
protected boolean	infix State flag for parsing context.
protected LinkedList<Object>	outputQueue
protected ExpressionParser	parser
protected Position	pos
protected Deque<Object>	stack

Constructor Summary

Constructors

Constructor and Description
ParseOperation(ExpressionParser parser, String expression)

Method Summary

Modifier and Type	Method and Description
protected char	currentChar()
protected char	futureChar(int offset)
protected boolean	isIdentifierPart(char c) Determines whether the given character is allowed to start an identifier.
protected boolean	isIdentifierStart(char c) Determines whether the given character is allowed to start an identifier.
protected Character	parseChar(char c) Attempts to parse the given character.
protected <CS extends CharSequence> CS	parseChars(CS cs) Attempts to parse the given characters.
protected String	parseElementSeparator() Attempts to parse an element separator symbol.
protected Group	parseGroupTerminator() Attempts to parse a group terminator symbol.
protected int	parseIdentifier() Attempts to parse an identifier, as defined by isIdentifierStart(char) and isIdentifierPart(char).
protected Object	parseLiteral() Attempts to parse a literal (e.g.
protected Operator	parseOperator() Attempts to parse an operator.
LinkedList<Object>	parsePostfix() Parses the expression into an output queue in Reverse Polish notation (i.e., postfix notation).
protected String	parseStatementSeparator() Attempts to parse a statement separator symbol.
protected String	parseToken(int length) Parses a token of the given length.
protected Variable	parseVariable() Attempts to parse a variable.
protected void	parseWhitespace() Skips past any whitespace to the next interesting character.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

parser

protected final ExpressionParser parser

expression

protected final String expression

pos

protected final Position pos

stack

protected final Deque<Object> stack

outputQueue

protected final LinkedList<Object> outputQueue

infix

protected boolean infix

State flag for parsing context.

• If true, we are expecting an infix or postfix operator next.
• If false, we are expecting a prefix operator or "noun" token (e.g., variable or literal) next.

Constructor Detail

ParseOperation

public ParseOperation(ExpressionParser parser,
                      String expression)

Method Detail

parsePostfix

public LinkedList<Object> parsePostfix()

Parses the expression into an output queue in Reverse Polish notation (i.e., postfix notation).

toString

public String toString()

Overrides:

toString in class Object

currentChar

protected char currentChar()

futureChar

protected char futureChar(int offset)

parseWhitespace

protected void parseWhitespace()

Skips past any whitespace to the next interesting character.

parseLiteral

protected Object parseLiteral()

Attempts to parse a literal (e.g. boolean, string, or number).

Returns:

The parsed literal, or null if the next token is not one.

See Also:

Literals.parseLiteral(java.lang.CharSequence)

parseVariable

protected Variable parseVariable()

Attempts to parse a variable.

Returns:

The parsed variable name, or null if the next token is not one.

parseIdentifier

protected int parseIdentifier()

Attempts to parse an identifier, as defined by isIdentifierStart(char) and isIdentifierPart(char).

Returns:

The length of the parsed identifier, or 0 if the next token is not one.

isIdentifierStart

protected boolean isIdentifierStart(char c)

Determines whether the given character is allowed to start an identifier.

The default implementation uses Character.isUnicodeIdentifierStart(char), but also accepts underscores, since many popular programming languages (e.g. Python and Java) allow identifiers to begin with an underscore symbol.

isIdentifierPart

protected boolean isIdentifierPart(char c)

Determines whether the given character is allowed to start an identifier.

The default implementation uses Character.isUnicodeIdentifierPart(char).

parseOperator

protected Operator parseOperator()

Attempts to parse an operator.

Returns:

The parsed operator, or null if the next token is not one.

parseGroupTerminator

protected Group parseGroupTerminator()

Attempts to parse a group terminator symbol.

Returns:

The group, or null if the next token is not a group terminator.

parseElementSeparator

protected String parseElementSeparator()

Attempts to parse an element separator symbol.

Returns:

The separator symbol, or null if the next token is not one.

parseStatementSeparator

protected String parseStatementSeparator()

Attempts to parse a statement separator symbol.

Returns:

The separator symbol, or null if the next token is not one.

parseChar

protected Character parseChar(char c)

Attempts to parse the given character.

Returns:

The character, or null if the next token is not that character.

parseChars

protected <CS extends CharSequence> CS parseChars(CS cs)

Attempts to parse the given characters.

Returns:

The characters, or null if the next tokens are not those characters.

parseToken

protected String parseToken(int length)

Parses a token of the given length.

Returns:

The parsed token.