How do you see the generated module names?

[mpdairy]

I have some complicated protos I'm trying to work with and would find it very helpful to see a list of the modules that are created from the proto files (or, at least, that would be created if I knew their names and could put them in exposed-modules). Is there some way to get a list of them?

[judah]

Unfortunately there isn't an automated way to get the names. It's probably something we could improve, for example as another flag to the proto-lens-protoc binary, or in the stderr of the setup script's output. We could also probably improve this in the documentation.

The logic is intentionally pretty simple:

proto-lens/proto-lens-protoc/src/Data/ProtoLens/Compiler/Plugin.hs

Line 94 in 0cb384a

-- | Get the Haskell module name corresponding to a given .proto file.

In short:

• Each path component of the filepath gets turned from snake_case into CamelCase (dropping the .proto extension).
• The primary module is those components together with ., plus a Proto. prefix.
• There's also another (optional) module with _Fields appended.

So for example, foo/bar_baz.proto turns into Proto.Foo.BarBaz and Proto.Foo.BarBaz_Fields.

[mpdairy]

Ok, thanks. I was thinking the Proto prefix came from the proto folder, which led to much confusion.

Is it true that you can only run defaultMainGeneratingProtos "proto" once in Setup.hs? I was writing a program that translates messages between two sets of proto files, and was forced to put them all in the same proto folder, which works for now, but it would be nicer if I could keep them separate.

[judah]

Yes, currently it only allows a single "root" directory per project. Two possible workarounds are:

• Create different Cabal libraries for the the different folders
• Symlink the different folders into one common location (which would add an additional prefix component to the module names).