4 ms·

> The remaining syntax has a lot of "but why?" where it just seems to do its own thing relative to other languages Like what? My list of Nix language nits is

by sshine 1y ago

> The remaining syntax has a lot of "but why?" where it just seems to do its own thing relative to other languages Like what? My list of Nix language nits is relatively small, would like to understand. One thing that seems under-developed is smart merging. There is // at language level, but then if you want datatype-specific merging, you use functions. That itself is just the power of functional programming. But as it is with untyped languages, you end up doing the same thing slightly different in several places, and a fractal of accidental complexity starts to appear.

chriswarbo 1y ago
> One thing that seems under-developed is smart merging. Maybe https://codeberg.org/amjoseph/infuse.nix https://codeberg.org/amjoseph/infuse.nix would be useful? (I find it intriguing, but haven't yet faced a use-case that seemed worth learning it)
positron26 1y ago
> Like what? I've heard people say "JSON with functions", but I think this is much too generous. - Functions can be called without delimiters - AttrSets have lots of delimiting, very explicit syntax - Lists have absolutely no delimiters again foo 1 2 is a function call, right? So if I need it in a list, I can just write: [ foo 1 2 ] right? Note, we pathologically put spaces around lists in Nix because we are subconsciously sure that something is about to bite us. [ foo 1 2 ] is a list of three elements, not a function call. I forget which terrible thing I was doing, but I had a variation of this syntax trap in my code after naively moving the expression into a list. The error message was, as usual, from the Turtles in Time dimension. The mixture of super explicit and implicit delimiting as well as borrowed ideas like \\ and invented ideas like with and import just make Nix feel like it's all over the place, inconsistent, and doing its own thing when we already had a lot of functional languages to work with. The evaluation model is completely appropriate for the problem yet pretty unique in programming generally. It has a lot of new ideas that throw even seasoned people well off track. Each new idea is not much, but they compound into not having any idea what we're looking at and watching 50k nixpkgs evaluate just fine while not being able to read any of that code at all. I'd prefer something like Haskell, Lisp, or Clojure, but please just one. Using Scheme in Guile is a great choice. It's so much easier to read. Hopefully the macros can be developed to bring the best of lazy evaluation into Scheme and fix the runtime issues.
- XorNot 1y ago
  Lately I've just been wondering if you couldn't have a python runtime for nix evaluations. Ultimately we're taking inputs, making derivations and calling some nix specific library functions. It feels like we should be able to do that with a Python library that would have the major advantage of being step debuggable.
- sshine 1y ago
  Nix function call syntax is completely standard for ML-style functional languages and allows for effortless partial application. The main downside is that error messages can get cryptic, especially so when Nix is untyped. Whitespace add list delimiter is not very common, but I have to admit I really like it. I was hoping for some “this doesn’t work” kind of things, not “this doesn’t feel familiar”. Not sure how Nix doesn’t win the readability contest: literally a config file with function calls, and as little superfluous syntax as possible. I’d say the real criticism is: Nix is hard to write, and nixpkgs idioms (nested, undocumentedabstractions scattered throughout the code) are hard to read.
  - yencabulator 1y ago
    > Not sure how Nix doesn’t win the readability contest Not sure how you can be serious. https://github.com/NixOS/nixpkgs/blob/d600f006643e074c2ef1d72e462e218b647a096c/pkgs/development/go-modules/generic/default.nix#L148-L166 https://github.com/NixOS/nixpkgs/blob/d600f006643e074c2ef1d7... buildGoDir() { local d; local cmd; cmd="$1" d="$2" . $TMPDIR/buildFlagsArray echo "$d" | grep -q "$/_\|examples\|Godeps\|testdata$" && return 0 [ -n "$excludedPackages" ] && echo "$d" | grep -q "$excludedPackages" && return 0 local OUT if ! OUT="$(go $cmd $buildFlags "''${buildFlagsArray[@]}" -v -p $NIX_BUILD_CORES $d 2>&1)"; then if ! echo "$OUT" | grep -qE '(no( buildable| non-test)?|build constraints exclude all) Go (source )?files'; then echo "$OUT" >&2 return 1 fi fi if [ -n "$OUT" ]; then echo "$OUT" >&2 fi return 0 } (Do note the Nix escaping on top of the shell horrors.) Nix just comes from a culture of utter utter horrible code. It's my daily driver, but I am holding my nose. https://github.com/NixOS/nix/blob/94ec9e47030c2a7280503d338f0dca7ad92811f5/src/nix-build/nix-build.cc#L483-L512 https://github.com/NixOS/nix/blob/94ec9e47030c2a7280503d338f... std::string rc = fmt( R"(_nix_shell_clean_tmpdir() { rm -rf %1%; }; )"s + (keepTmp ? "trap _nix_shell_clean_tmpdir EXIT; " "exitHooks+=(_nix_shell_clean_tmpdir); " "failureHooks+=(_nix_shell_clean_tmpdir); ": "_nix_shell_clean_tmpdir; ") + (pure ? "" : "[ -n \"$PS1\" ] && [ -e ~/.bashrc ] && source ~/.bashrc;") + "%2%" "dontAddDisableDepTrack=1;\n" + structuredAttrsRC + "\n[ -e $stdenv/setup ] && source $stdenv/setup; " "%3%" "PATH=%4%:\"$PATH\"; " "SHELL=%5%; " "set +e; " R"s([ -n "$PS1" -a -z "$NIX_SHELL_PRESERVE_PROMPT" ] && PS1='\n\[\033[1;32m\][nix-shell:\w]\$\[\033[0m\] '; )s" "if [ \"$(type -t runHook)\" = function ]; then runHook shellHook; fi; " "unset NIX_ENFORCE_PURITY; " "shopt -u nullglob; " "unset TZ; %6%" "shopt -s execfail;" "%7%", shellEscape(tmpDir), (pure ? "" : "p=$PATH; "), (pure ? "" : "PATH=$PATH:$p; unset p; "), shellEscape(dirOf(*shell)), shellEscape(*shell), (getenv("TZ") ? (string("export TZ=") + shellEscape(getenv("TZ")) + "; ") : ""), envCommand);

by sshine 1y ago

chriswarbo 1y ago

> One thing that seems under-developed is smart merging. Maybe https://codeberg.org/amjoseph/infuse.nix https://codeberg.org/amjoseph/infuse.nix would be useful? (I find it intriguing, but haven't yet faced a use-case that seemed worth learning it)

positron26 1y ago

> Like what? I've heard people say "JSON with functions", but I think this is much too generous. - Functions can be called without delimiters - AttrSets have lots of delimiting, very explicit syntax - Lists have absolutely no delimiters again foo 1 2 is a function call, right? So if I need it in a list, I can just write: [ foo 1 2 ] right? Note, we pathologically put spaces around lists in Nix because we are subconsciously sure that something is about to bite us. [ foo 1 2 ] is a list of three elements, not a function call. I forget which terrible thing I was doing, but I had a variation of this syntax trap in my code after naively moving the expression into a list. The error message was, as usual, from the Turtles in Time dimension. The mixture of super explicit and implicit delimiting as well as borrowed ideas like \\ and invented ideas like with and import just make Nix feel like it's all over the place, inconsistent, and doing its own thing when we already had a lot of functional languages to work with. The evaluation model is completely appropriate for the problem yet pretty unique in programming generally. It has a lot of new ideas that throw even seasoned people well off track. Each new idea is not much, but they compound into not having any idea what we're looking at and watching 50k nixpkgs evaluate just fine while not being able to read any of that code at all. I'd prefer something like Haskell, Lisp, or Clojure, but please just one. Using Scheme in Guile is a great choice. It's so much easier to read. Hopefully the macros can be developed to bring the best of lazy evaluation into Scheme and fix the runtime issues.

XorNot 1y ago
Lately I've just been wondering if you couldn't have a python runtime for nix evaluations. Ultimately we're taking inputs, making derivations and calling some nix specific library functions. It feels like we should be able to do that with a Python library that would have the major advantage of being step debuggable.
sshine 1y ago
Nix function call syntax is completely standard for ML-style functional languages and allows for effortless partial application. The main downside is that error messages can get cryptic, especially so when Nix is untyped. Whitespace add list delimiter is not very common, but I have to admit I really like it. I was hoping for some “this doesn’t work” kind of things, not “this doesn’t feel familiar”. Not sure how Nix doesn’t win the readability contest: literally a config file with function calls, and as little superfluous syntax as possible. I’d say the real criticism is: Nix is hard to write, and nixpkgs idioms (nested, undocumentedabstractions scattered throughout the code) are hard to read.
- yencabulator 1y ago
  > Not sure how Nix doesn’t win the readability contest Not sure how you can be serious. https://github.com/NixOS/nixpkgs/blob/d600f006643e074c2ef1d72e462e218b647a096c/pkgs/development/go-modules/generic/default.nix#L148-L166 https://github.com/NixOS/nixpkgs/blob/d600f006643e074c2ef1d7... buildGoDir() { local d; local cmd; cmd="$1" d="$2" . $TMPDIR/buildFlagsArray echo "$d" | grep -q "$/_\|examples\|Godeps\|testdata$" && return 0 [ -n "$excludedPackages" ] && echo "$d" | grep -q "$excludedPackages" && return 0 local OUT if ! OUT="$(go $cmd $buildFlags "''${buildFlagsArray[@]}" -v -p $NIX_BUILD_CORES $d 2>&1)"; then if ! echo "$OUT" | grep -qE '(no( buildable| non-test)?|build constraints exclude all) Go (source )?files'; then echo "$OUT" >&2 return 1 fi fi if [ -n "$OUT" ]; then echo "$OUT" >&2 fi return 0 } (Do note the Nix escaping on top of the shell horrors.) Nix just comes from a culture of utter utter horrible code. It's my daily driver, but I am holding my nose. https://github.com/NixOS/nix/blob/94ec9e47030c2a7280503d338f0dca7ad92811f5/src/nix-build/nix-build.cc#L483-L512 https://github.com/NixOS/nix/blob/94ec9e47030c2a7280503d338f... std::string rc = fmt( R"(_nix_shell_clean_tmpdir() { rm -rf %1%; }; )"s + (keepTmp ? "trap _nix_shell_clean_tmpdir EXIT; " "exitHooks+=(_nix_shell_clean_tmpdir); " "failureHooks+=(_nix_shell_clean_tmpdir); ": "_nix_shell_clean_tmpdir; ") + (pure ? "" : "[ -n \"$PS1\" ] && [ -e ~/.bashrc ] && source ~/.bashrc;") + "%2%" "dontAddDisableDepTrack=1;\n" + structuredAttrsRC + "\n[ -e $stdenv/setup ] && source $stdenv/setup; " "%3%" "PATH=%4%:\"$PATH\"; " "SHELL=%5%; " "set +e; " R"s([ -n "$PS1" -a -z "$NIX_SHELL_PRESERVE_PROMPT" ] && PS1='\n\[\033[1;32m\][nix-shell:\w]\$\[\033[0m\] '; )s" "if [ \"$(type -t runHook)\" = function ]; then runHook shellHook; fi; " "unset NIX_ENFORCE_PURITY; " "shopt -u nullglob; " "unset TZ; %6%" "shopt -s execfail;" "%7%", shellEscape(tmpDir), (pure ? "" : "p=$PATH; "), (pure ? "" : "PATH=$PATH:$p; unset p; "), shellEscape(dirOf(*shell)), shellEscape(*shell), (getenv("TZ") ? (string("export TZ=") + shellEscape(getenv("TZ")) + "; ") : ""), envCommand);