Redefinition of `reflect` lacks View-Hints

[WojciechKarpiel]

Hi!

Thank you for writing the book, I enjoy learning from it!

In chapter 5 "Views and Boolean reflection", reader is encouraged to redefine reflect (note that in the actual code definition is wrapped in a module): https://github.com/ilyasergey/pnp/blob/master/coq/BoolReflect.v#L680 then the book redefines andP (original code uses the o ssrbool.reflect, while a reader likely uses his own version of reflect): https://github.com/ilyasergey/pnp/blob/master/coq/BoolReflect.v#L728 then the book defines andb_orb, which relies on elimTF View-Hint, which is absent from reader-defined reflect (therefore type-checking fails): https://github.com/ilyasergey/pnp/blob/master/coq/BoolReflect.v#L777 then the book explains that elimTF is necessary (if it didn't, then I'd be totally in the dark about what went wrong :P): https://github.com/ilyasergey/pnp/blob/master/coq/BoolReflect.v#L815

My problem is that reader fails to prove andb_orb when following the book. I suggest changing the text so that there is no unexpected type-checking failure. For example, either:

• Introduce elimTF View-Hint for user-defined reflect.
• Define andP' instead of andP, and refer to ssrbool's andP during proof of andb_orb

[ilyasergey]

Dear Wojciech,

Thank you for the suggestion. Please, feel free to arrange them as a PR – I'll be happy to review and adopt them once they are considered acceptable.