Variable scoping broken?

[michaelpj]

Updating to 0.11, all our uses of PyF broke. I can't even make the example from the README work any more:

GHCi, version 8.10.7: https://www.haskell.org/ghc/  :? for help
Prelude> import PyF
Prelude PyF> :set -XQuasiQuotes
Prelude PyF> name = "Dave"
Prelude PyF> age = 54
Prelude PyF> [fmt|Person's name is {name}, age is {age}|]

<interactive>:5:24: error:
    • Variable not in scope: name
    • In the quasi-quotation:
        [fmt|Person's name is {name}, age is {age}|]
Prelude PyF> 

This is very weird!

[guibou]

Thank you for this report.

That's indeed really weird.

I'm using some magic with template Haskell to check for name and apparently this is broken in the context of GHCI.

I cannot reproduce using cabal repl:

$ nix develop .#pyf_810
$ cabal repl
GHCi, version 8.10.7: https://www.haskell.org/ghc/  :? for help

... build output
Ok, 8 modules loaded.
*PyF> :set -XQuasiQuotes 
*PyF> age = 54
*PyF> name = "Dave"
*PyF> [fmt|Persan's name is {name}, age is {age}|]
(... defaulting warnings)
"Persan's name is Dave, age is 54"

I will investigate what is happening with a different ghci or cabal setup.

[guibou]

Does it works outside of a repl, when compiling the file?

[michaelpj]

Hmmmm, my initial problem was in a compiled file (I think all of them). I just reported the GHCi example because it seemed like a smoking gun! I'll see if I can make a smaller reproducer.

[michaelpj]

Some confusing progress... it works on macos and not on linux! :scream:

[michaelpj]

Notes:

• This only happens with a haskell.nix project
• Using the same GHC from the project on PyF itself works fine
• So it's some weird problem with the built version of the package?

Overall I think this is likely something very specific on our end, rather than a problem in PyF. I'll reopen if we find something.