Issues using List/map + dhall-format

[purcell-nec]

Probably doing something stupid here, but given the following:

in  let envToStr = λ(e : { name : Text, val : Text }) → e.name ++ "=" ++ e.val

in  let List/map =
          https://ipfs.io/ipfs/QmQ8w5PLcsNz56dMvRtq54vbuPe9cNnCCUXAQp6xLc6Ccx/Prelude/List/map 

in  let toEnv =
            λ(es : List { name : Text, val : Text })
          → List/map { name : Text, val : Text } Text envToStr es

then dhall-format converts List/map on the last line to List /map, and I get Error: Missing file. dhall-format doesn't munge List/head in the same way, which is odd.

If I disable dhall-format then I get the same error, though.

Using dhall 1.8 from stackage nightly 2017-11-25, on MacOS.

[Gabriella439]

I believe Dhall's parser used to support this in older versions but doesn't any longer once I standardized the grammar. Like you noticed, List/map is a valid parse for List applied to the file /map and that parse takes priority over parsing it as a single variable name. In fact, I think some examples in the tutorial use this idiom and they need to be fixed

Normally you would fix this using a lexer with a longest-match rule, but the Dhall language cannot support a separate lexing step because some language features fundamentally conflict with lexing (specifically: nested block comments and string interpolation).

You can work around this by just prefixing the variable name with anything like Prelude/List/map, or just calling it map

[purcell-nec]

Ah, thanks - that works. I was going off the examples at https://hackage.haskell.org/package/dhall-1.8.0/docs/Dhall-Tutorial.html#g:20, fyi.

[Gabriella439]

I'll reopen this just to remind myself to fix the tutorial examples

[Gabriella439]

Fixed by dhall-lang/dhall-haskell@834c1b6

[Gabriella439]

It turns out that there might be a way to fix the original issue after all to support identifier names like List/map. See: #83

[purcell-nec]

Nice!