QuotedString and escaping Quotes

[Iván de Prado]

Hello, 

I am having a problem when giving parameters to a load function that
loads data from a database. It receives a SQL query as parameter.
Something like that:

A = LOAD 'dbparams.cfg' USING  DBPigStorage('select if(field is null,
\'null\',field) from table');

But I am having a problem with quotes. I don't know how to escape quotes
in order to insert them into a quotedString. 

I have taken a look to the grammar file:

<quotedstring> := "'"<string>"'"

But doesn't say nothing about string and escaping. Can I escape the
quotes in a quotedstring using "\'"? 

If they are not any escaping in quoted strings, I propose to add
java-like escaping with "\". 

Any other solution?

Thanks, 
Iván de Prado Alonso
www.ivanprado.es