String quotation about odata-filter-to-ast

[petrzjunior]

@lezsakdomi That's a good point I missed! You are correct as this is from the grammar:

stringLiteral    = SQUOTE *( SQUOTE-in-string / pchar-no-SQUOTE ) SQUOTE
SQUOTE-in-string = SQUOTE SQUOTE ; two consecutive single quotes represent one within a string literal
SQUOTE = "'" / "%27"

I thing that the most sane thing would be to make a breaking change and switch to single quotes to conform to the specification. This ensures that user would not be surprised by the behavior on a conforming input.

I initially created this project for my personal use but it is getting some traction on npm. I want this to remain a small implementation of a subset of OData. There are other projects which generate parser from the whole grammar, this is out of scope of this project. Still, I would be very much interested in improving conformace in the parts this library already covers.

I'll try to fix this in a few days. In case you find any more inconsistencies, feel free to report them, add tests or even open a PR.