au.com.codeka.carrot.expr

Class StatementParser

java.lang.Object

au.com.codeka.carrot.expr.StatementParser

public class StatementParser
extends java.lang.Object

StatementParser is used to parse expressions. Expressions are used to refer to everything that appears after the Tag in a TagNode, and has the following pseudo-EBNF grammar:

   expression = ["!"] notcond

   notcond = andcond {"&&" andcond}

   andcond = orcond {"||" orcond}

   orcond =
     comparator [("=="|"!="|"<"|"<="|">="|">") comparator]

   comparator = ["+"|"-"] term {("+"|"-") term}

   term = factor {("*" | "/") factor}

   factor =
     variable
     | number
     | literal
     | "(" expression ")"

   variable = identifier [func-call] ["[" expression "]"] ["." variable]

   func-call = "." identifier "(" expression {"," expression} ")"

   identifier = "any valid Java identifier"
   number = "and valid Java number"
   literal = """ anything """
 

The statement parser allows you to extract any sub-element from a string as well (for example, the ForTag wants to pull off it's arguments an identifier followed by the identifier "in" followed by a statement.

Constructor Summary

Constructors

Constructor and Description
StatementParser(Tokenizer tokenizer)

Method Summary

Modifier and Type	Method and Description
Identifier	maybeParseIdentifier() Tries to parse an identifier from the stream and returns it if we parsed it, otherwise returns null.
void	parseEnd() Parses the "end" of the statement.
Expression	parseExpression()
Identifier	parseIdentifier()
NumberLiteral	parseNumber()
StringLiteral	parseString()

Methods inherited from class java.lang.Object

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

Constructor Detail

StatementParser

public StatementParser(Tokenizer tokenizer)

Method Detail

parseEnd

public void parseEnd()
              throws CarrotException

Parses the "end" of the statement. Just verifies that there's no unexpected tokens after the end.

Throws:

CarrotException - if we're not actually at the end of the statement.

maybeParseIdentifier

@Nullable
public Identifier maybeParseIdentifier()
                                          throws CarrotException

Tries to parse an identifier from the stream and returns it if we parsed it, otherwise returns null.

Returns:

The Identifier we parsed, or null if we couldn't parse an identifier.

Throws:

CarrotException - if there's some error parsing the identifer.

parseIdentifier

public Identifier parseIdentifier()
                           throws CarrotException

Throws:

CarrotException

parseNumber

public NumberLiteral parseNumber()
                          throws CarrotException

Throws:

CarrotException

parseString

public StringLiteral parseString()
                          throws CarrotException

Throws:

CarrotException

parseExpression

public Expression parseExpression()
                           throws CarrotException

Throws:

CarrotException