djs: the LDC 1.43.0 frontend ported to TypeScript (preview)

[Paolo Invernizzi]

I've been porting the frontend of LDC 1.43.0 to TypeScript: 
lexer, parser, semantic analysis, CTFE, ImportC, Ddoc, -vcg-ast 
and -X. It runs in-process in Node, no code generation.

https://github.com/DeepGlance/djs

On the DMD test suite shipped with LDC it gives ldmd2's exit 
status, stdout and stderr byte for byte, and every module of 
druntime and Phobos compiles with the same output, -vcg-ast 
included. The import tree is bundled, so there's nothing to 
install besides Node 22.

Why: a VS Code extension that compiles in a worker thread, with 
hover, go to definition, completion, semantic tokens and inlay 
hints answered by the real frontend, no language server. That one 
is coming shortly.

Limits: macOS arm64 and Linux hosts only, DMD-style x86 asm is 
skipped with a warning (licence reasons, see LICENSE), it's 10x 
slower than ldmd2 and hungry on memory. It's a preview, 0.1.0.

About the AI discussion in the other thread: the port was done 
with Claude agents, whole files at a time, against a written 
guide, with the test suite as the judge. I think this is the kind 
of AI work that pays for everybody, including who doesn't want AI 
anywhere near their editor: there's no model in djs or in the 
extension, it's the same D, the same frontend and the same 
diagnostics as LDC, Boost licensed. The guide is in docs/porting, 
if someone wants to apply the same method to other pieces of the 
D house.

Feedback welcome, especially from anyone who tries it on Linux, 
which I couldn't test against an ldc2 here.

/P