Parsing latex-like language in Java

Question

I\'m trying to write a parser in Java for a simple language similar to Latex, i.e. it contains lots of unstructured text with a couple of \\commands[with]{some}{parameters}

Answer 1

You can define a grammar to accept the Latex input, using just characters as tokens in the worst cast. JavaCC should be just fine for this purpose.

The good thing about a grammar and a parser generator is that it can parse things that FSAs have trouble with, especially nested structures.

A first cut at your grammar could be (I'm not sure this is valid JavaCC, but it is reasonable EBNF):

 Latex = item* ;
 item = command | rawtext ;
 command =  command arguments ;
 command = '\' letter ( letter | digit )* ;  -- might pick this up as lexeme
 letter = 'a' | 'b' | ... | 'z' ;
 digit= '0' | ...  | '9' ;
 arguments =  epsilon |  '{' item* '}' ;
 rawtext = ( letter | digit | whitespace | punctuationminusbackslash )+ ; -- might pick this up as lexeme
 whitespace = ' ' | '\t' | '\n' | '\:0D' ; 
 punctuationminusbackslash = '!' | ... | '^' ;