Vendoring `build/lambda/` files

[cafkafk]

Hi, over at NixOS/nixpkgs#242101 (review), we wanted to make use of the make file more directly when building lambda-lisp.

It would be very helpful if lambdalisp could vendor those files, or at least check for their existence before calling wget, as we can't make network requests from the nix sandbox.

[woodrush]

I have an interpreter that I wrote by myself which I can include in this repo, except it's written in Haskell, so it would create a Haskell dependency. Would that still help?

[cafkafk]

Hmm, probably not I'm afraid

[woodrush]

I see. I'll be adding existence checks before wget. Would throwing an error if the files are nonexistent be enough?

[cafkafk]

I think so, as long as it would skip the wget in those cases, probably should be good

[woodrush]

I tried running wget with a nonexistent URL (returns 404), and it returned a nonzero return code. Running it within a Makefile stopped the Make process at wget. So essentially, there's already an existence check in wget, since if the URL starts returning a 404 it would stop Make. I could add wget --spider ... for another explicit check, but I'm not sure if that's what we want here.

[cafkafk]

Wait no, sorry, I'm pretty sure I got confused. What I need is for it to check if the file already exists, and if it does, skip wget. The problem right now is that we wanna provide those files ourselves, because we can't have network access, and when we try to use make it fails because it tries to reach the internet.

Sorry for the confusion!

[woodrush]

Oh I see! No problem, thanks for the clarification. In that case, the local existence check is done by the Makefile itself. Right now, the recipe for "making" the interpreter source files (*.c) is to wget it. So if *.c already exists, make won't run the recipe for *.c, so the wget would not be triggered.

So to prevent wget from running, I believe it should be enough if the source files are manually placed in build/ before running make.

[cafkafk]

Ohh I see, I'll try that, thanks!