dotfiles/.config/nixpkgs/elvish/carapace-nix-build.patch

commit 29cf307f93c19325ff09f0e324624abd4f6bb7ba
Author: Thomas Dy <thatsmydoing@gmail.com>
Date:   Sun Jan 15 18:05:45 2023 +0900

    nix-build: add initial support

diff --git a/completers/nix-build_completer/cmd/root.go b/completers/nix-build_completer/cmd/root.go
new file mode 100644
index 00000000..65381edd
--- /dev/null
+++ b/completers/nix-build_completer/cmd/root.go
@@ -0,0 +1,39 @@
+package cmd
+
+import (
+	"github.com/rsteube/carapace"
+	"github.com/rsteube/carapace-bin/pkg/actions/tools/nix"
+	"github.com/spf13/cobra"
+)
+
+var rootCmd = &cobra.Command{
+	Use:   "nix-build",
+	Short: "build a Nix expression",
+	Long:  "https://nixos.org/manual/nix/stable/command-ref/nix-build.html",
+	Run:   func(cmd *cobra.Command, args []string) {},
+}
+
+func Execute() error {
+	return rootCmd.Execute()
+}
+func init() {
+	carapace.Gen(rootCmd).Standalone()
+
+	rootCmd.Flags().StringP("include", "I", "", "Include paths")
+	rootCmd.Flags().Bool("no-out-link", false, "Do not create a symlink to the output path")
+	rootCmd.Flags().StringP("out-link", "o", "", "Change the name of the symlink to the output path")
+	rootCmd.Flags().Bool("dry-run", false, "Show what store paths would be built or downloaded")
+	rootCmd.Flags().StringP("attr", "A", "", "Attribute to build")
+	// TODO support --arg and --argstr
+
+	carapace.Gen(rootCmd).PositionalAnyCompletion(nix.ActionPaths())
+	carapace.Gen(rootCmd).FlagCompletion(carapace.ActionMap{
+		"attr": nix.ActionAttr(rootCmd, func(_ *cobra.Command, c carapace.Context) string {
+			if len(c.Args) > 0 {
+				return c.Args[0]
+			} else {
+				return "default.nix"
+			}
+		}),
+	})
+}
diff --git a/completers/nix-build_completer/main.go b/completers/nix-build_completer/main.go
new file mode 100644
index 00000000..a733fad2
--- /dev/null
+++ b/completers/nix-build_completer/main.go
@@ -0,0 +1,7 @@
+package main
+
+import "github.com/rsteube/carapace-bin/completers/nix-build_completer/cmd"
+
+func main() {
+	cmd.Execute()
+}
diff --git a/pkg/actions/tools/nix/attr.go b/pkg/actions/tools/nix/attr.go
new file mode 100644
index 00000000..921bf2b6
--- /dev/null
+++ b/pkg/actions/tools/nix/attr.go
@@ -0,0 +1,82 @@
+package nix
+
+import (
+	_ "embed"
+	"encoding/json"
+	"fmt"
+	"path"
+	"strings"
+
+	"github.com/rsteube/carapace"
+	"github.com/spf13/cobra"
+)
+
+//go:embed attrComplete.nix
+var attrCompleteScript string
+
+func ActionAttr(cmd *cobra.Command, getSource func(*cobra.Command, carapace.Context) string) carapace.Action {
+	return carapace.ActionCallback(func(c carapace.Context) carapace.Action {
+		attrPath := c.CallbackValue
+		nixPath := ""
+		if cmd.Flag("include").Changed {
+			nixPath = cmd.Flag("include").Value.String()
+		}
+
+		source := getSource(cmd, c)
+
+		if strings.HasPrefix(source, "<") {
+			// expression is a local channel, use as-is
+		} else if strings.HasPrefix(source, "http:") || strings.HasPrefix(source, "https:") {
+			// expression is a url, wrap in fetchTarball
+			source = fmt.Sprintf("(fetchTarball %s)", source)
+		} else if strings.HasPrefix(source, "channel:") {
+			// expression is a channel alias, convert to url
+			channelName := source[8:]
+			source = fmt.Sprintf("(fetchTarball https://nixos.org/channels/%s/nixexprs.tar.xz)", channelName)
+		} else {
+			// expression is a local file
+			filePath := path.Clean(source)
+			if path.Base(filePath) == filePath {
+				// paths must have at least one `/`
+				filePath = fmt.Sprintf("./%s", filePath)
+			}
+			source = filePath
+		}
+		expression := fmt.Sprintf("import %s", source)
+
+		// nix itself handles quotes weirdly so we just avoid them altogether
+		if strings.Contains(attrPath, "\"") {
+			return carapace.ActionMessage("attrPath may not contain double-quotes")
+		}
+
+		// strip right-most attr
+		lastDotIndex := strings.LastIndex(attrPath, ".")
+		if lastDotIndex >= 0 {
+			attrPath = attrPath[0:lastDotIndex]
+		} else {
+			attrPath = ""
+		}
+
+		args := []string{
+			"--eval", "--json",
+			"--expr", attrCompleteScript,
+			"--arg", "__carapaceInput__", expression,
+			"--argstr", "__carapaceAttrPath__", attrPath,
+		}
+		if nixPath != "" {
+			args = append(args, "-I", nixPath)
+		}
+		// TODO handle passing through --arg and --argstr from original command
+
+		return carapace.ActionExecCommand("nix-instantiate", args...)(func(output []byte) carapace.Action {
+			var data []string
+			json.Unmarshal(output, &data)
+			if attrPath != "" {
+				for i, value := range data {
+					data[i] = fmt.Sprintf("%s.%s", attrPath, value)
+				}
+			}
+			return carapace.ActionValues(data...)
+		})
+	})
+}
diff --git a/pkg/actions/tools/nix/attrComplete.nix b/pkg/actions/tools/nix/attrComplete.nix
new file mode 100644
index 00000000..4f98d858
--- /dev/null
+++ b/pkg/actions/tools/nix/attrComplete.nix
@@ -0,0 +1,25 @@
+all@{ __carapaceInput__, __carapaceAttrPath__, ... }:
+let
+  inputArgs = builtins.removeAttrs all ["__carapaceInput__" "__carapaceAttrPath__"];
+
+  input =
+    if builtins.isFunction __carapaceInput__ then
+      __carapaceInput__ inputArgs
+    else
+      __carapaceInput__;
+
+  autocall = fnOrAttrset:
+    if builtins.isFunction fnOrAttrset then
+      fnOrAttrset {}
+    else
+      fnOrAttrset;
+
+  paths = builtins.filter (path: (builtins.isString path) && path != "") (builtins.split "\\." __carapaceAttrPath__);
+
+  reducer = attrset: name: autocall (builtins.getAttr name attrset);
+  result = builtins.foldl' reducer input paths;
+in
+  if builtins.isAttrs result then
+    builtins.attrNames result
+  else
+    []
diff --git a/pkg/actions/tools/nix/path.go b/pkg/actions/tools/nix/path.go
new file mode 100644
index 00000000..e3dbc8b2
--- /dev/null
+++ b/pkg/actions/tools/nix/path.go
@@ -0,0 +1,29 @@
+package nix
+
+import (
+	"strings"
+
+	"github.com/rsteube/carapace"
+)
+
+// ActionPaths completes paths
+//
+// A path can be one of:
+//   - a local file path (default.nix)
+//   - an http/https URL (https://releases.nixos.org/../nixexprs.tar.xz
+//   - a channel: specifier (channel:nixos-22.05)
+//   - a local channel (<nixpkgs>)
+func ActionPaths() carapace.Action {
+	return carapace.ActionCallback(func(c carapace.Context) carapace.Action {
+		arg := c.CallbackValue
+		if strings.HasPrefix(arg, "<") {
+			return ActionLocalChannels().Invoke(c).Prefix("<").Suffix(">").ToA()
+		} else if strings.HasPrefix(arg, "http:") || strings.HasPrefix(arg, "https:") {
+			return carapace.ActionValues()
+		} else if strings.HasPrefix(arg, "channel:") {
+			return ActionRemoteChannels().Invoke(c).Prefix("channel:").ToA()
+		} else {
+			return carapace.ActionFiles()
+		}
+	})
+}