'DynFlag'-free version of 'mkParserFlags'
Obtaining a DynFlags is difficult, making using the lexer/parser
for pure parsing/lexing unreasonably difficult, even with
This is despite the fact that we only really need
- language extension flags
- warning flags
- a handful of boolean options
The new mkParserFlags' function makes is easier to directly construct
a ParserFlags. Furthermore, since pExtsBitmap is just a footgun,
I've gone ahead and made ParserFlags an abstract type.
Reviewers: bgamari, alanz, sjakobi
Reviewed By: bgamari, sjakobi
Subscribers: mpickering, sjakobi, rwbarton, carter
GHC Trac Issues: Trac #11301
Differential Revision: https://phabricator.haskell.org/D5269