Package com.singularsys.jep.configurableparser.matchers

Class FunctionSequenceGrammarMatcher

  • All Implemented Interfaces:
    GrammarMatcher, java.io.Serializable
    public class FunctionSequenceGrammarMatcher
extends java.lang.Object
implements GrammarMatcher
    A GrammarMatcher which matches functions in the form atan2(seq) where seq is a sequence of terms. This differs from FunctionGrammarMatcher in that the sequence operator (usually ",") is treated like a normal operator and parsed in the main ShuntingYard class. So arguments 1,2,3,4 is parsed as a single subexpression rather than as four subexpressions. The function must be in the FunctionTable and brackets are required.

    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("(",")","[","]"); 
 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:
    BracketedSequenceGrammarMatcher, CPSeqOpTest, Serialized Form

    • Constructor Detail

      • FunctionSequenceGrammarMatcher

        public FunctionSequenceGrammarMatcher​(Token open,
                                      Token close,
                                      Operator seqOp)
        Create a FunctionGrammarMatcher
        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.

      • errorToken

        protected Token errorToken​(Lookahead2Iterator<Token> it)
        Generate a token to use in GrammarExecptions
        Parameters:
        it - used to get current position
        Returns:
        a TerminatorToken

      • match

        public Node match​(Lookahead2Iterator<Token> it,
                  GrammarParser parser)
           throws ParseException
        Attempt to match a function, calls the GrammarParser.parseSubExpression() to match function arguments.
        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.

      • buildList

        public void buildList​(Node top,
                      java.util.List<Node> seq)