I’m wondering how long it’ll be before I can build syntax extensions with beta/stable. Is there an ETA?
Stable syntax extensions are part of the plan for Rust over the next year (see the “Plugins” section). @nrc is doing most of the work here, and the first steps are the “HIR” (RFC/design doc, tracking issue):
Currently the AST is used by libsyntax for syntactic operations, by the compiler for pretty much everything, and in syntax extensions. I propose splitting the AST into a libsyntax version that is specialised for syntactic operation and will eventually be stabilised for use by syntax extensions and tools, and the HIR which is entirely internal to the compiler.
I guess RFC issue 440 somewhat serves as a tracking issue for syntax extensions themselves.
That’s everything I wanted to know. Thanks!