regex - Handling different escaping sequences?

Question

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.

Answer 1

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 ''
           )*
      '''
    ;