pkgs/vim: Add rustfmt with custom default config

Since I do have a lot of projects where I use rustfmt, it gets pretty
tedious to manually run "cargo fmt". Using g:rustfmt_autosave should
make this less tedious but it might annoy me in the future, let's see.

In addition to setting rustfmt I also added a default path for rustc,
which is used whenever there is no rustc in path. This is because I
usually switch between several projects which use different Rust
versions and this way it will use the rustc version that is in PATH
during "nix develop".

For the rustfmt part I also added a small default configuration which
represents my opinion on how I think Rust code should be formatted. The
file is used whenever a project doesn't have a "rustfmt.toml" or
".rustfmt.toml".

Unfortunately, RustFmt is broken in Vim right now[1], so I'm using the
upstream project until the issue has been resolved.

[1]: https://github.com/rust-lang/rust.vim/issues/446

Signed-off-by: aszlig <aszlig@nix.build>

4 files changed, 63 insertions, 1 deletions

diff --git a/pkgs/aszlig/default.nix b/pkgs/aszlig/default.nix
index 58f372a9..0629ab8e 100644
--- a/pkgs/aszlig/default.nix
+++ b/pkgs/aszlig/default.nix
@@ -1,4 +1,4 @@
-{ callPackage, callPackage_i686, vim_configurable, gopass, mutt, xterm }:
+{ callPackage, vim_configurable, gopass, mutt, xterm, rustfmt }:
 
 {
   aacolorize = callPackage ./aacolorize { };
@@ -12,6 +12,7 @@
   nlast = callPackage ./nlast { };
   psi = callPackage ./psi { };
   pvolctrl = callPackage ./pvolctrl { };
+  rustfmt = callPackage ./rustfmt { inherit rustfmt; };
   vim = callPackage ./vim { vim = vim_configurable; };
   xterm = callPackage ./xterm { inherit xterm; };
 }
diff --git a/pkgs/aszlig/rustfmt/config.patch b/pkgs/aszlig/rustfmt/config.patch
new file mode 100644
index 00000000..0a49a585
--- /dev/null
+++ b/pkgs/aszlig/rustfmt/config.patch
@@ -0,0 +1,13 @@
+diff --git a/src/config/mod.rs b/src/config/mod.rs
+index cd90e090..a6db6da1 100644
+--- a/src/config/mod.rs
++++ b/src/config/mod.rs
+@@ -282,7 +282,7 @@ impl Config {
+                 }
+             }
+ 
+-            Ok(None)
++            Ok(Some(env!("DEFAULT_CONFIG_FILE").into()))
+         }
+ 
+         match resolve_project_file(dir)? {
diff --git a/pkgs/aszlig/rustfmt/default.nix b/pkgs/aszlig/rustfmt/default.nix
new file mode 100644
index 00000000..cde4d010
--- /dev/null
+++ b/pkgs/aszlig/rustfmt/default.nix
@@ -0,0 +1,31 @@
+{ rustfmt, runCommand, remarshal }:
+
+let
+  defaultConfig = {
+    format_code_in_doc_comments = true;
+    format_macro_matchers = true;
+    format_strings = true;
+    group_imports = "StdExternalCrate";
+    match_block_trailing_comma = true;
+    max_width = 79;
+    newline_style = "Unix";
+    normalize_doc_attributes = true;
+    overflow_delimited_expr = true;
+    reorder_impl_items = true;
+    unstable_features = true;
+    use_field_init_shorthand = true;
+    use_try_shorthand = true;
+    wrap_comments = true;
+  };
+
+in rustfmt.overrideAttrs (drv: {
+  patches = (drv.patches or []) ++ [ ./config.patch ];
+  patchFlags = [ "-p1" "-d" "src/tools/rustfmt" ];
+  DEFAULT_CONFIG_FILE = runCommand "rustfmt.conf" {
+    nativeBuildInputs = [ remarshal ];
+    value = builtins.toJSON defaultConfig;
+    passAsFile = [ "value" ];
+  } ''
+    json2toml "$valuePath" "$out"
+  '';
+})
diff --git a/pkgs/aszlig/vim/default.nix b/pkgs/aszlig/vim/default.nix
index 5162dc8c..35711e00 100644
--- a/pkgs/aszlig/vim/default.nix
+++ b/pkgs/aszlig/vim/default.nix
@@ -1,5 +1,6 @@
 { stdenv, lib, fetchurl, fetchFromGitHub, writeText, writeTextFile, writeScript
 , runCommand, writers, python3Packages, ledger, meson, vim, buildGoPackage
+, rustc, rustfmt
 }:
 
 let
@@ -403,6 +404,14 @@ let
       rev = "e38845b4042d2351c47cd63f8705fd51c97acb4f";
       sha256 = "1k3val0ibriwcv5jdyq95sgxgkz54r15gpylbhns5934zvaakpj1";
     };
+
+    # Remove once https://github.com/rust-lang/rust.vim/issues/446 is resolved.
+    rust = fetchFromGitHub {
+      owner = "rust-lang";
+      repo = "rust.vim";
+      rev = "4aa69b84c8a58fcec6b6dad6fe244b916b1cf830";
+      sha256 = "07nh8gvkwq91i7qcz0rk5jlc8sb4d3af4zq2892kmmw576zg1wd8";
+    };
   };
 
   generic = ''
@@ -578,6 +587,14 @@ let
     let g:Hexokinase_highlighters = ['background']
     let g:Hexokinase_refreshEvents =
       \ ['TextChanged', 'TextChangedI', 'InsertLeave', 'BufRead']
+
+    " rust
+    if !executable('rustc')
+      let g:rustc_path = '${rustc}/bin/rustc'
+    endif
+    let g:rustfmt_command = '${rustfmt}/bin/rustfmt'
+    let g:rustfmt_autosave = 1
+    let g:rust_recommended_style = 0
   '';
 
   autocmd = ''