How could I subclass the lexer and parser?

[dmtvanzanten]

I would like to add an 'AboutEqual' operator to the query such that the query field aeq number would get mapped to a query that uses func.abs(Table.field - number) < 0.1*number. How could I do this? I'm quite new to SLY, but looking at the metaclasses it uses, it seems not very trivial to subclass. Would you have any advice?

[dmtvanzanten]

I proceeded with looking how this could be added to the package instead. I made a PR (#62) to demonstrate some example code on how this could be done.