Kicking off libproc_macro

[cgswords]

This PR introduces libproc_macro, which is currently quite bare-bones (just a few macro construction tools and an initial quote! macro).

This PR also introduces a few test cases for it, and an additional shim file (at src/libsyntax/ext/proc_macro_shim.rs to allow a facsimile usage of Macros 2.0 today!

[rust-highfive]

r? @alexcrichton

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[cgswords]

r? @nrc

Whoops, forgot to tag @nrc for reviewer.

[nrc]

deps are inconsistent between here, the Cargo.toml, and the extern crates

[nrc]

I'm not sure I know what you mean.

I thought we landed your quote macro in libsyntax, which means with this PR there are two copies in the codebase. Can we remove the one from libsyntax? (Or am I misremembering landing it?)

[nrc]

r=me with tests passing and perhaps removing the old quote (if it exists)

[cgswords]

You're misremembering. This is the first quote macro.

[eddyb]

@cgswords Can you squash?

[cgswords]

@eddyb Done!

[eddyb]

@cgswords Looking more at it, I think you'll need to start a rustbuild build to update Cargo.lock.

[cgswords]

@eddyb That should do that.

[eddyb]

@bors r=nrc

[bors]

📌 Commit d9d6e8c has been approved by nrc

[bors]

⌛ Testing commit d9d6e8c with merge 38002f1...

[cgswords]

Er, accidental re-push. Travis is failing because tidy reports that I have libproc_macro in librustc_driver's toml file, but don't use it in the driver. Is there a different Cargo.toml I can put it in? (I can't extern crate it because it defines a plugin.) (cc @alexcrichton for the proper fix)

[eddyb]

@cgswords I would actually expect it to depend on nothing but libstd, and libsyntax to depend on it, in the long run.

[cgswords]

@eddyb I can't imagine why libsyntax would rely on it; it's the user-facing abstraction over libsyntax, so it internally needs access to that.

[eddyb]

@cgswords My intuition is reversed, having libsyntax be a grammar wrapper around libmacro.

Either way, can you make libsyntax_ext use it? That should solve the dependency rooting problem.

[cgswords]

@eddyb That won't stop it from throwing the "plugin as library" warning. @alexcrichton how should we shim this?

[alexcrichton]

@cgswords you can add an entry to the whitelist here

[cgswords]

Whitelist entry added.

[eddyb]

@bors r=nrc

[bors]

📌 Commit 98c8e0a has been approved by nrc

[bors]

⌛ Testing commit 98c8e0a with merge 1bf5fa3...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-cargotest, auto-linux-64-cross-freebsd, auto-linux-64-debug-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-opt-no-mir, auto-linux-64-opt-rustbuild, auto-linux-64-x-android-t, auto-linux-cross-opt, auto-linux-musl-64-opt, auto-mac-32-opt, auto-mac-64-opt, auto-mac-64-opt-rustbuild, auto-mac-cross-ios-opt, auto-win-gnu-32-opt, auto-win-gnu-32-opt-rustbuild, auto-win-gnu-64-opt, auto-win-msvc-32-opt, auto-win-msvc-64-cargotest, auto-win-msvc-64-opt, auto-win-msvc-64-opt-no-mir, auto-win-msvc-64-opt-rustbuild
Approved by: nrc
Pushing 1bf5fa3 to master...

[cgswords]

🤘