Re: packaging Typst

[Steve George]

Hi Alexis,

I've been doing some Rust packaging recently, so maybe this will help you to 
get started. Here's how I would approach it.

Explore the software
====================
The first thing I did was explore whether Typst builds in a current Guix 
environment. If we don't have the right version of Rust, for example, there's 
little point continuing:

- clone it into an appropriate place
- start a shell: 
    $ guix shell --container --network rust rust-cargo coreutils openssl 
nss-certs gcc-toolchain

We need 'openssl' and 'nss-certs' so that cargo will work. 

- build it: 
    [env]$ env CC=gcc cargo build

Kept failing on ring v0.17.5 which is looking for 'cc'. It builds with 296 
crates, so we might have our hands full here! Eventually outputs a 
/target/debug/typst command which seems to work.


Import using Guix import
=========================
Normally, we'd be able to use the `crates` importer. But, the Typst crates are 
just place-holders with no details. 

AFAIK the importer only works with crates-io, we can't feed it Cargo.toml file 
directly. We'll need to manually create a package and check for any 
dependencies.

Manually create a top-level package
====================================
To manually create the package we have to go through the projects Cargo.toml.

- create an intial typst.scm file in some project directory.
- create a minimal typst package by looking in Cargo.lock at 'typst'
- for each dependency look at what the Cargo.lock used to build it - check 
whether we have it in Guix
- in some cases we will have the crate, but not the right version

Import the dependencies
=============================
The first crate that I found which we don't have in the Guix archive is 
'comemo' [0]. We can import this with: 

    $ guix shell --development guix --container --nesting --network nss-certs
    [env]$ guix import crate --recursive comemo@0.3.0 > comemo-import.scm

Move these package definitions into your main `typst.scm` file. Check them to 
add any missing development dependencies.

The first one in the dependency stack is `rust-comemo-0.3` which we reference 
at the bottom of the file. We try and build it as the importer has pulled it in:

    $ guix shell --development guix --container --nesting 
    [env]$ guix build --load-path=./ --file=typst.scm
    <successfully builds>

The next one `rust-comemo-macros` which has been set to `skip-build: #t`, we'll 
try building it that way initially:

    - add rust-comemo-macros-0.3 to the bottom of the typst.scm file
    - comment out the rust-comemo-0.3 line
    - try and build with: guix build --load-path=./ --file=typst.scm 

    - If it builds successfully, change the `skip-build: #t` part of the 
definition to be #f.
        - error[E0433]: failed to resolve: use of undeclared crate or module 
`comemo`
            - tried adding comemo as a dependency which didn't work
            - set it to #:tests? #f - for now

There's some more things that have to be done to 'contribute' these packages, 
but for now I would move onto the next dependency. And that's all there is to 
this part - finding the dependencies and importing them.

Building a dependent package that's not a crate
===============================================
The cargo-build-system expects to build everything from Crates AFAIK. I believe 
it will take some messing around with the phases to add the typst-lib which 
seems to be a dependency. It looks like librsvg (in gnome.scm) does a lot of 
messing with phases, and greetd (in admin.scm) does some as well - these might 
be good examples to look at.

Hopefully this is enough to get you started!

Steve

[0] https://crates.io/crates/comemo

typst.scm
Description: Text document