[SOLVED] Handling different escaping sequences?

Handling different escaping sequences?

I'm using ANTLR with Presto grammar in order to parse SQL queries. This is the original string definition I've used to parse queries:

STRING
    : '\'' ( '\\' .
           | ~[\\']       // match anything other than \ and '
           | '\'\''       // match ''
           )*
      '\''
    ;

This worked ok for most queries until I saw queries with different escaping rules. For example:

select 
table1(replace(replace(some_col,'\\'',''),'\"' ,'')) as features 
from table1

So I've modified my String definition and now it looks like:

STRING
    : '\'' ( '\\' .
           | '\\\\'  .  {HelperUtils.isNeedSpecialEscaping(this)}?       // match \ followed by any char
           | ~[\\']       // match anything other than \ and '
           | '\'\''       // match ''
           )*
      '\''
    ;

However, this won't work for the query mentioned above as I'm getting

'\\'',''),'

as a single string. The predicate returns True for the following query. Any idea how can I handle this query as well?

Thanks, Nir.

Solution

In the end I was able to solve it. This is the expression I was using:

STRING
    : '\'' ( '\\\\'  .  {HelperUtils.isNeedSpecialEscaping(this)}?
           | '\\' (~[\\] | . {!HelperUtils.isNeedSpecialEscaping(this)}?)
           | ~[\\']       // match anything other than \ and '
           | '\'\''       // match ''
           )*
      '\''
    ;