Remy Goldschmidt taktoa

Online things

Package search (for stable channel)
- An unofficial multi-channel package search (for all recent channels, including stable - currently not being updated)
Options search (for stable channel)
A list of channels, and when they were last updated
A timeline of channel builds
A source code search (that actually works!) of all NixOS repositories; Nix, nixpkgs, etc.

Development tooling

GHC API lets you process Haskell sources, and (among other) specify code generation and linking level. For example:

(1) no codegen & no link
(2) bytecode generation & link in memory
(3) machine code generation & linking output binaries

For code analysis purposes, based on generating the typechecked AST, option (1) suffices most of the time. There are some situations in which it doesn't:

TemplateHaskell (TH) splice needs to execute code (at compile time) from an imported module: the imported module must be available in compiled form, so either (2) or (3) is needed. Example: in $([|$(foo)|]), foo will be evaluated at compile-time.
Code uses FFI imports. For this one would expect that (2) is needed (see checkCOrAsmOrLlvmOrInterp in TcForeign.hs), but actually unless it is used (say by TH, see below), even (1) works too (see the wrapper checkCg).

Lower precedence means a stronger binding; ie. this list is sorted from strongest to weakest binding, and in the case of equal precedence between two operators, the associativity decides the binding.

Prec	Abbreviation	Example	Assoc	Description
1	SELECT	`e . attrpath [or def]`	none	Select attribute denoted by the attribute path `attrpath` from set `e`. (An attribute path is a dot-separated list of attribute names.) If the attribute doesn’t exist, return `default` if provided, otherwise abort evaluation.
2	APP	`e1 e2`	left	Call function `e1` with argument `e2`.
3	NEG	`-e`	none	Numeric negation.
4	HAS_ATTR	`e ? attrpath`	none	Test whether set `e` contains the attribute denoted by `attrpath`; return true or false.
5	CONCAT	`e1 ++ e2`	right	List concatenation.
6	MUL	`e1 * e2`	le

this has been rewritten yet again as most workarounds aren't required anymore since wine 3+

example video of the final result: https://www.youtube.com/watch?v=zkqzQoeOGfU

with touchscreen: https://www.youtube.com/watch?v=GcIrlorWmaQ

performance is indistinguishable from windows. there might be a very slight ~25ms sound latency which is easily compensated with +25 local offset

tested on

General notes

nix-channel and ~/.nix-defexpr are gone. We'll use $NIX_PATH (or user environment specific overrides configured via nix set-path) to look up packages. Since $NIX_PATH supports URLs nowadays, this removes the need for channels: you can just set $NIX_PATH to e.g. https://nixos.org/channels/nixos-15.09/nixexprs.tar.xz and stay up to date automatically.
By default, packages are selected by attribute name, rather than the name attribute. Thus nix install hello is basically equivalent to nix-env -iA hello. The attribute name is recorded in the user environment manifest and used in upgrades. Thus (at least by default) hello won't be upgraded to helloVariant.

@vcunat suggested making this an arbitrary Nix expression rather than an attrpath, e.g. firefox.override { enableFoo = true; }. However, such an expression would not have a key in the user environment, unlike an attrpath. Better to require an explicit flag for this.

TBD: How to deal with search path clashes.

	Uninstalling nix:
	1. Delete /Library/LaunchDaemons/org.nixos.nix-daemon.plist

	sudo launchctl unload /Library/LaunchDaemons/org.nixos.nix-daemon.plist
	sudo rm /Library/LaunchDaemons/org.nixos.nix-daemon.plist

	2. Restore /etc/profile.backup-before-nix back to /etc/profile

	sudo mv /etc/profile.backup-before-nix /etc/profile

	self: super: let
	mkXDG = import ../xdg.nix;
	in

	{
	wget = mkXDG {
	pname = "wget";
	pkg = super.wget;
	mods = { cache }: {
	wget.flags = "--hsts-file=${cache}/hsts";

	{ system ? builtins.currentSystem }:

	# In order to update `nixpkgs.json` to a specific revision, run:
	#
	# ```bash
	# $ nix-prefetch-git https://github.com/NixOS/nixpkgs.git "${REVISION}" > nixpkgs.json
	# ```

	with rec {
	builtin-paths = import <nix/config.nix>;

	{ pkgs ? import <nixpkgs> { } }:

	with pkgs;

	stdenv.mkDerivation rec {
	name = "gnome-builder-${version}";
	version = "3.25.2-a11c9dfa";

	buildInputs = [
	libxml2 desktop_file_utils llvm clang libgit2 gobjectIntrospection librsvg

	{-# LANGUAGE DataKinds #-}
	{-# LANGUAGE DefaultSignatures #-}
	{-# LANGUAGE DeriveAnyClass #-}
	{-# LANGUAGE DeriveGeneric #-}
	{-# LANGUAGE FlexibleContexts #-}
	{-# LANGUAGE KindSignatures #-}
	{-# LANGUAGE NamedFieldPuns #-}
	{-# LANGUAGE OverloadedStrings #-}
	{-# LANGUAGE RecordWildCards #-}
	{-# LANGUAGE ScopedTypeVariables #-}