CODEWITHSUNDEEP
parsingantlrantlr4lexer
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Reputation: 21

How to parse a single escape character between escape characters using ANTLR

I have a string like RANDOM = "SOMEGIBBERISH ("DOG CAT-DOG","DOG CAT-DOG")". For quoted string literals I use:

StringLiteralSQ : UnterminatedStringLiteralSQ '\'' ;
UnterminatedStringLiteralSQ : '\'' (~['\r\n] | '\\' (. | EOF))* ;   
StringLiteralDQ : UnterminatedStringLiteralDQ '"' ;
UnterminatedStringLiteralDQ : '"' (~[\r\n] | '\\' (. | EOF))* ;

This parses the above mentioned String. I need to identify them words as comma separated tokens like this DOG CAT-DOG. for this I use something like

options : name EQUALS value
  | OPTIONS L_PAREN (name EQUALS value) (COMMA (name EQUALS value)* R_PAREN
  ;

However, when I make the string of this format RANDOM = "SOMEGIBBERISH ("DOG CAT-DOG"DOG CAT-DOG")", it fails with an out-of-memory error.

I wanted to parse the strings that I have been parsing before and also parse this kind of string ("DOG CAT-DOG"DOG CAT-DOG") and consider it a single token maybe. How can I do that?

Upvotes: 0

Views: 256

Answers (1)

Mike Lischke
Mike Lischke

Reputation: 53337

Your question is a bit confusing, so I'm not sure I understand what you are after. You ask for handling escaped characters, but then you don't show any input which uses escapes.

However, I think you are making things way too complicated. Look in other grammars to see how they define string tokens, including escape handling. Here's a typical example:

fragment SINGLE_QUOTE: '\'';
fragment DOUBLE_QUOTE: '"';

DOUBLE_QUOTED_TEXT: (
        DOUBLE_QUOTE ('\\'? .)*? DOUBLE_QUOTE
    )+
;

SINGLE_QUOTED_TEXT: (
        SINGLE_QUOTE ('\\'? .)*? SINGLE_QUOTE
    )+
;

Upvotes: 1

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