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:

  value =
     variable
     | number
     | literal
     | "(" expression ")"
     | empty-term

   unary-term = ["!"] unary-term

   multiplicative-term = unnary-term [("*" | "/") multiplicative-term]

   additive-term = multiplicative-term [("+" | "-") additive-term]

   relational-term = additive-term [("<" | <=" | ">" | >=" | "in") relational-term]

   equality-term = relational-term [("==" | "!=") equality-term]

   and-term = equality-term ["&&" and-term]

   or-term = and-term ["||" or-term]

   ternary-term = or-term ["?" variable ":" variable]

   emtpy-term =

   expression = ternary-term ["," expression]

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

   func-call = "." identifier "(" 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
boolean	isAssignment()
Identifier	maybeParseIdentifier() Tries to parse an identifier from the stream and returns it if we parsed it, otherwise returns null.
java.util.List<Identifier>	maybeParseIdentifierList() Attempts to parse an identifier list.
void	parseEnd() Parses the "end" of the statement.
Identifier	parseIdentifier()
java.util.List<Identifier>	parseIdentifierList()
Term	parseTerm()
Term	parseTermsIterable()
Token	parseToken(TokenType type)

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

@Nonnull
public Identifier parseIdentifier()
                                     throws CarrotException

Throws:

CarrotException

parseToken

@Nonnull
public Token parseToken(@Nonnull
                                  TokenType type)
                           throws CarrotException

Throws:

CarrotException

maybeParseIdentifierList

public java.util.List<Identifier> maybeParseIdentifierList()
                                                    throws CarrotException

Attempts to parse an identifier list. If there's no identifier to begin the list, returns null.

Returns:

The list of Identifiers we parsed, or null if we couldn't parse an identifier.

Throws:

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

parseIdentifierList

public java.util.List<Identifier> parseIdentifierList()
                                               throws CarrotException

Throws:

CarrotException

isAssignment

public boolean isAssignment()
                     throws CarrotException

Throws:

CarrotException

parseTerm

public Term parseTerm()
               throws CarrotException

Throws:

CarrotException

parseTermsIterable

public Term parseTermsIterable()
                        throws CarrotException

Throws:

CarrotException