Merge #3800

3800: Introduce ra_proc_macro_srv r=matklad a=edwin0cheng

This PR add preliminary for server side of proc macro : 

1. Add crate setup
2. IO for server side


Co-authored-by: Edwin Cheng <[email protected]>

1 files changed, 21 insertions, 0 deletions

diff --git a/crates/ra_proc_macro_srv/src/lib.rs b/crates/ra_proc_macro_srv/src/lib.rs
new file mode 100644
index 000000000..f77be1475
--- /dev/null
+++ b/crates/ra_proc_macro_srv/src/lib.rs
@@ -0,0 +1,21 @@
+//! RA Proc Macro Server
+//!
+//! This library is able to call compiled Rust custom derive dynamic libraries on arbitrary code.
+//! The general idea here is based on https://github.com/fedochet/rust-proc-macro-expander.
+//!
+//! But we change some several design for fitting RA needs:
+//!
+//! * We use `ra_tt` for proc-macro `TokenStream` server, it is easy to manipute and interact with
+//!   RA then proc-macro2 token stream.
+//! * By **copying** the whole rustc `lib_proc_macro` code, we are able to build this with `stable`
+//!   rustc rather than `unstable`. (Although in gerenal ABI compatibility is still an issue)
+
+use ra_proc_macro::{ExpansionResult, ExpansionTask, ListMacrosResult, ListMacrosTask};
+
+pub fn expand_task(_task: &ExpansionTask) -> Result<ExpansionResult, String> {
+    unimplemented!()
+}
+
+pub fn list_macros(_task: &ListMacrosTask) -> Result<ListMacrosResult, String> {
+    unimplemented!()
+}