From 18b216ca27b31f92b52f509ece2039119937e897 Mon Sep 17 00:00:00 2001
From: Brian Hicks <brian@brianthicks.com>
Date: Wed, 3 Jun 2020 08:37:01 -0500
Subject: [PATCH] import from my dotfiles

---
 LICENSE         |  4 +++
 README.md       | 68 +++++++++++++++++++++++++++++++++++++++++++++++++
 default.nix     | 15 +++++++++++
 similar-sort.go | 68 +++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 155 insertions(+)
 create mode 100644 LICENSE
 create mode 100644 README.md
 create mode 100644 default.nix
 create mode 100644 similar-sort.go

diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..704a88d
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,4 @@
+similar-sort is licensed CC BY-SA 4.0.
+
+"Wait, why?", I hear you say, "That's an unusual choice for source code!"
+Put quite simply, it's because this package is a wrapper around a Levenshtein distance implementation I got from WikiPedia, which is licensed under CC BY-SA 3.0.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..a5e6b6e
--- /dev/null
+++ b/README.md
@@ -0,0 +1,68 @@
+# Similar Sort
+
+This is a small Go program that will:
+
+1. take a reference string as the first argument
+2. and a list of candidate strings in stdin
+3. and output the candidates sorted according to their edit distance from the reference, lowest first.
+
+"What use is this?" you may ask!
+Well!
+It turns out to be really useful to do fuzzy file finding a large project.
+
+When I am in some filesystem hierarchy and I trigger my fuzzy-finder, I want to see sibling files before I see similarly-named files further away.
+I also want to match on test files pretty easily.
+Say I have this project structure:
+
+```
+example
+└── src
+    ├── Main.elm
+    └── Page
+        └── Learn
+            └── Home
+                ├── Main.elm
+                └── View.elm
+```
+
+If I am in `src/Page/Learn/Home/View.elm` and I want to get to the sibling file `Main.elm`, the default `fzf` config shows me `src/Main.elm` first.
+That's not what I wanted!
+
+But if I sort the files instead by passing them through `similar-sort src/Page/Learn/Home/View.elm`, the sibling file will show up first.
+This works surprisingly well, and I really like it!
+
+It could probably perform a *little* better by doing some heuristic based on equivalent file structure except for the addition/removal of "tests", "specs", etc, but I haven't bothered yet.
+
+## Installing
+
+You can look in `dotfiles/kakoune.nix` in the root of this project to see how to use this in a home-manager context.
+If you're not using home-manager, or you just want to install it globally, `cd` here and type:
+
+```sh
+nix-env -if .
+```
+
+OR if you have `go` installed but not `nix`, just `go build similar-sort.go`; it has no external dependencies and will result in a static binary you can put wherever.
+
+### Adding to Vim
+
+Add this to your vim config:
+
+```vim
+nnoremap <silent> <C-t> :call fzf#run(fzf#wrap({
+  \ "source": "git ls-files --others --cached --exclude-standard \| similar-sort " . @% . " \| grep -v " . @%,
+  \ "sink": "edit",
+  \ "options": "--tiebreak index"
+  \ }))<CR>
+```
+
+(You'll need `fzf` and `fzf.vim` installed.)
+This will bind ctrl-t to the fuzzy finder.
+When you select a match, it will open in the current pane.
+
+If you want to split or vsplit, change `"sink": "edit"` to `"sink": "split"` or `"sink": "vsplit"`.
+See the docs for `fzf#run` for more customization options.
+
+### Adding to Kakoune
+
+I use [connect.kak](https://github.com/alexherbo2/connect.kak) to spawn a terminal window with about the same command line as in the vim config above.
diff --git a/default.nix b/default.nix
new file mode 100644
index 0000000..1a1dc76
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,15 @@
+{ pkgs ? import <nixpkgs> { }, ... }:
+pkgs.stdenv.mkDerivation {
+  name = "similar-sort";
+  buildInputs = [ pkgs.go ];
+  src = ./.;
+
+  buildPhase = ''
+    env HOME=$(pwd) GOPATH=$(pwd) go build similar-sort.go
+  '';
+
+  installPhase = ''
+    mkdir -p $out/bin
+    cp similar-sort $out/bin
+  '';
+}
diff --git a/similar-sort.go b/similar-sort.go
new file mode 100644
index 0000000..41b0736
--- /dev/null
+++ b/similar-sort.go
@@ -0,0 +1,68 @@
+package main
+
+import "bufio"
+import "fmt"
+import "os"
+import "sort"
+import "strings"
+import "unicode/utf8"
+
+func main() {
+	target := strings.Join(os.Args[1:], " ")
+
+	s := bufio.NewScanner(os.Stdin)
+	var lines []WithDistance
+	for s.Scan() {
+		lines = append(lines, WithDistance{s.Text(), Levenshtein(target, s.Text())})
+	}
+
+	sort.Slice(lines, func(i, j int) bool {
+		return lines[i].distance < lines[j].distance
+	})
+
+	for _, line := range lines {
+		fmt.Println(line.text)
+	}
+}
+
+type WithDistance struct {
+	text     string
+	distance int
+}
+
+// https://en.wikibooks.org/wiki/Algorithm_Implementation/Strings/Levenshtein_distance#Go
+// made available under CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0/
+func Levenshtein(a, b string) int {
+	f := make([]int, utf8.RuneCountInString(b)+1)
+
+	for j := range f {
+		f[j] = j
+	}
+
+	for _, ca := range a {
+		j := 1
+		fj1 := f[0] // fj1 is the value of f[j - 1] in last iteration
+		f[0]++
+		for _, cb := range b {
+			mn := min(f[j]+1, f[j-1]+1) // delete & insert
+			if cb != ca {
+				mn = min(mn, fj1+1) // change
+			} else {
+				mn = min(mn, fj1) // matched
+			}
+
+			fj1, f[j] = f[j], mn // save f[j] to fj1(j is about to increase), update f[j] to mn
+			j++
+		}
+	}
+
+	return f[len(f)-1]
+}
+
+func min(a, b int) int {
+	if a <= b {
+		return a
+	} else {
+		return b
+	}
+}