Polyglot Developer

Environments

Warsaw, 2023

Developer environment

editor
debugging tools
version control system tools
native libraries
additional binaries
remote resources

What this talk is about?

Unix philosophy

synergy between tools

tools

The regular approach

Pros:

(tightly) integrated environment
works out of the box
great support for major languages & frameworks
debugging tools

Cons:

limited extendability
does not play well with things that it wasn't integrated with
lack of support for less popular languages

Reasons to use various languages

right tool for the job
personal preference
willingness to learn & experiment
legacy/existing project written in XY

Setting up the environment

(if lucky) follow instructions in README.md
run a provided shell script and pray for it not to fail with some obscure error
how to make the editor aware of the environment?

how to propagate updates across developer environments
use docker?

$ cd workspace/projectA
$ code .

Reasons to fail

outdated/unclear instructions
script does not support our system
we have such an environment for X but it uses a different version of Y
having to master rbenv, sdkman, nvm, ...
inherent flaws

Meet Nix

declarative package manager
reproducible build tool
functional language

Recipe

Binary

Linking

Example

{
  inputs.nixpkgs.url = "github:nixos/nixpkgs";
  inputs.flake-utils.url = "github:numtide/flake-utils";

  outputs = { nixpkgs, flake-utils, ... }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs { inherit system; };
      in
      {
        devShell = pkgs.mkShell {
          buildInputs = with pkgs; [
            (sbt.override {
              jre = temurin-jre-bin-17;
            })
            nodejs
            yarn
          ];
        };
      }
    );
}

devShell = pkgs.mkShell {
  buildInputs = with pkgs; [
    (sbt.override {
      jre = temurin-jre-bin-17;
    })
    nodejs
    yarn
  ];
};

How it works?

~ $ cd projectA

~ $ cd projectA
~/projectA $ which sbt
sbt not found

~ $ cd projectA
~/projectA $ which sbt
sbt not found
~/projectA $ which nodejs
nodejs not found

~ $ cd projectA
~/projectA $ which sbt
sbt not found
~/projectA $ which nodejs
nodejs not found
~/projectA $ nix develop
[15.1/0.0 MiB DL] downloading 'https://github.com/NixOS/nixpkgs/...'

~ $ cd projectA
~/projectA $ which sbt
sbt not found
~/projectA $ which nodejs
nodejs not found
~/projectA $ nix develop
[15.1/0.0 MiB DL] downloading 'https://github.com/NixOS/nixpkgs/...'
~/projectA $ which node                                                                                                                                                                                                                                           21:17:14
/nix/store/4bgg8j8275adawqbc5rkm4fv48dgg2i3-nodejs-18.18.2/bin/node
~/projectA $ which sbt                                                                                                                                                                                                                                            21:17:11
/nix/store/k9xwny18ihx78qh8pyxrnz7mrbqj962p-sbt-1.9.7/bin/sbt

~ $ cd projectA
~/projectA $ which sbt
sbt not found
~/projectA $ which nodejs
nodejs not found
~/projectA $ nix develop
[15.1/0.0 MiB DL] downloading 'https://github.com/NixOS/nixpkgs/...'
~/projectA $ which node                                                                                                                                                                                                                                           21:17:14
/nix/store/4bgg8j8275adawqbc5rkm4fv48dgg2i3-nodejs-18.18.2/bin/node
~/projectA $ which sbt                                                                                                                                                                                                                                            21:17:11
/nix/store/k9xwny18ihx78qh8pyxrnz7mrbqj962p-sbt-1.9.7/bin/sbt
~/projectA $ exit
~/projectA $ which sbt
sbt not found

How it works?

Nix store

/nix/store/zzpm91md3wqllaqpzm7whvcpa /nix/store/zzpss56rnqxmhsg01v72762ha /nix/store/zzqbcqjn05771v42fy9q97chk /nix/store/zzqk32qc4imypcifq9jz1wif5 /nix/store/zzqnsgnpsfnrhwg8s4g9ci0dn /nix/store/zzrajbcphf2f6spria8c7szwr /nix/store/zzrgf0qw8vd3rd3fznzif1fh5 /nix/store/zzsgwdfagsw6xq6fvs7yycpvq /nix/store/zzsm2ynsib3ddkjxw7g0j8v47

$ cd ~/workspace/projectA
# will use jdk11 and python2.7

$ cd ~/workspace/projectB
# will use jdk19 and node16

$ cd ~/workspace/projectC
# will use python3 and node17

PATH:=

Use direnv to automatically enable nix shell when entering project directory

?

Nix

Direnv

Meet Neovim

runs inside terminal
build on top of years of experience from building vim
easy to extend via lua scripts
follows unix philosophy of modularity and simplicity
builtin support for language server protocol

Language Server Protocol

LSP

Editors

Language servers

completions
diagnostics
navigation
code lenses
code actions
refactorings
and many more...

is this enough to develop software?

Language Server Protocol

Treesitter

General enough to parse any programming language
Fast enough to parse on every keystroke in a text editor
Robust enough to provide useful results even in the presence of syntax errors
Dependency-free so that the runtime library (which is written in pure C) can be embedded in any application