Package com.singularsys.jep.configurableparser.matchers

Class BracketedSequenceGrammarMatcher

java.lang.Object

com.singularsys.jep.configurableparser.matchers.BracketedSequenceGrammarMatcher

All Implemented Interfaces:

GrammarMatcher, java.io.Serializable

public class BracketedSequenceGrammarMatcher
extends java.lang.Object
implements GrammarMatcher

A GrammarMatcher which matches lists of items with the syntax or a simple list [1,2,3,4]. This differs from the ListGrammarMatcher in that the comma operator is treated like a normal operator and parsed using the ShuntingYard. So 1,2,3,4 is parsed as a single subexpression rather than as four subexpressions.

To set up first a new sequence operator must be created. This should be a binary operator with right associativity. It should have a precedence level lower than all other operators. This operator should be passed to the constructor of the FunctionSequenceGrammarMatcher and possibly also the BracketedSequenceGrammarMatcher.

 OperatorTable2 ot = new StandardOperatorTable2();
 Operator seqOp = new Operator(",", null, Operator.BINARY+Operator.RIGHT);
 ot.appendOperator(new OperatorKey() {}, seqOp, optab.getAssign()); // lower precedence than assignment
 
 ConfigurableParser cp = new ConfigurableParser();
 cp.addHashComments();
 cp.addSlashComments();
 cp.addSingleQuoteStrings();
 cp.addDoubleQuoteStrings();
 cp.addWhiteSpace();
 cp.addExponentNumbers();
 cp.addSymbols("(",")","[","]"); // "," not include in symbols
 cp.setImplicitMultiplicationSymbols("(","["); 
 cp.addOperatorTokenMatcher();
 cp.addIdentifiers();
 cp.addSemiColonTerminator();
 cp.addWhiteSpaceCommentFilter();
 cp.addBracketMatcher("(",")"); 
 
 // Add the function matcher
 cp.addGrammarMatcher(new FunctionSequenceGrammarMatcher(
                cp.getSymbolToken("("),
                cp.getSymbolToken(")"),
                seqOp));
 // Add the bracket matcher
 cp.addGrammarMatcher(new BracketedSequenceGrammarMatcher(
                cp.getSymbolToken("["),
                cp.getSymbolToken("]"),
                seqOp
                )); 
 cp.addArrayAccessMatcher("[","]");
 Jep jep = new Jep(ot,cp);
 

See Also:

FunctionSequenceGrammarMatcher, CPSeqOpTest, Serialized Form

Constructor Summary

Constructors

Constructor	Description
BracketedSequenceGrammarMatcher(Token open, Token close, Operator seqOp)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	init(Jep jep)	Delayed initialisation, this methods is called whenever components of the jep instance are changed.
Node	match(Lookahead2Iterator<Token> it, GrammarParser parser)	Test whether the input matches this pattern.

Methods inherited from class java.lang.Object

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

Constructor Detail

BracketedSequenceGrammarMatcher

public BracketedSequenceGrammarMatcher(Token open,
                                       Token close,
                                       Operator seqOp)

Constructor. The operator for the list is found in the init() method

Parameters:

open - token representing an opening bracket

close - token representing a closing bracket

seqOp - operator representing the sequence

Method Detail

init

public void init(Jep jep)

Description copied from interface: GrammarMatcher

Delayed initialisation, this methods is called whenever components of the jep instance are changed.

Specified by:

init in interface GrammarMatcher

Parameters:

jep - the current jep instance.

match

public Node match(Lookahead2Iterator<Token> it,
                  GrammarParser parser)
           throws ParseException

Description copied from interface: GrammarMatcher

Test whether the input matches this pattern.

Specified by:

match in interface GrammarMatcher

Parameters:

it - An iterator inspecting the input

parser - the parser to use when evaluating sub expressions

Returns:

if matched returns a node representing the content, return null is does not match

Throws:

ParseException - if there is a syntactical error in the input.