DesktopAppInfo sucks for sorting the matched apps for best results, use fzy instead

helpers/fzy.lua

@@ -0,0 +1,275 @@
+-- The lua implementation of the fzy string matching algorithm
+
+local SCORE_GAP_LEADING = -0.005
+local SCORE_GAP_TRAILING = -0.005
+local SCORE_GAP_INNER = -0.01
+local SCORE_MATCH_CONSECUTIVE = 1.0
+local SCORE_MATCH_SLASH = 0.9
+local SCORE_MATCH_WORD = 0.8
+local SCORE_MATCH_CAPITAL = 0.7
+local SCORE_MATCH_DOT = 0.6
+local SCORE_MAX = math.huge
+local SCORE_MIN = -math.huge
+local MATCH_MAX_LENGTH = 1024
+
+local fzy = {}
+
+-- Check if `needle` is a subsequence of the `haystack`.
+--
+-- Usually called before `score` or `positions`.
+--
+-- Args:
+--   needle (string)
+--   haystack (string)
+--   case_sensitive (bool, optional): defaults to false
+--
+-- Returns:
+--   bool
+function fzy.has_match(needle, haystack, case_sensitive)
+  if not case_sensitive then
+    needle = string.lower(needle)
+    haystack = string.lower(haystack)
+  end
+
+  local j = 1
+  for i = 1, string.len(needle) do
+    j = string.find(haystack, needle:sub(i, i), j, true)
+    if not j then
+      return false
+    else
+      j = j + 1
+    end
+  end
+
+  return true
+end
+
+local function is_lower(c)
+  return c:match("%l")
+end
+
+local function is_upper(c)
+  return c:match("%u")
+end
+
+local function precompute_bonus(haystack)
+  local match_bonus = {}
+
+  local last_char = "/"
+  for i = 1, string.len(haystack) do
+    local this_char = haystack:sub(i, i)
+    if last_char == "/" or last_char == "\\" then
+      match_bonus[i] = SCORE_MATCH_SLASH
+    elseif last_char == "-" or last_char == "_" or last_char == " " then
+      match_bonus[i] = SCORE_MATCH_WORD
+    elseif last_char == "." then
+      match_bonus[i] = SCORE_MATCH_DOT
+    elseif is_lower(last_char) and is_upper(this_char) then
+      match_bonus[i] = SCORE_MATCH_CAPITAL
+    else
+      match_bonus[i] = 0
+    end
+
+    last_char = this_char
+  end
+
+  return match_bonus
+end
+
+local function compute(needle, haystack, D, M, case_sensitive)
+  -- Note that the match bonuses must be computed before the arguments are
+  -- converted to lowercase, since there are bonuses for camelCase.
+  local match_bonus = precompute_bonus(haystack)
+  local n = string.len(needle)
+  local m = string.len(haystack)
+
+  if not case_sensitive then
+    needle = string.lower(needle)
+    haystack = string.lower(haystack)
+  end
+
+  -- Because lua only grants access to chars through substring extraction,
+  -- get all the characters from the haystack once now, to reuse below.
+  local haystack_chars = {}
+  for i = 1, m do
+    haystack_chars[i] = haystack:sub(i, i)
+  end
+
+  for i = 1, n do
+    D[i] = {}
+    M[i] = {}
+
+    local prev_score = SCORE_MIN
+    local gap_score = i == n and SCORE_GAP_TRAILING or SCORE_GAP_INNER
+    local needle_char = needle:sub(i, i)
+
+    for j = 1, m do
+      if needle_char == haystack_chars[j] then
+        local score = SCORE_MIN
+        if i == 1 then
+          score = ((j - 1) * SCORE_GAP_LEADING) + match_bonus[j]
+        elseif j > 1 then
+          local a = M[i - 1][j - 1] + match_bonus[j]
+          local b = D[i - 1][j - 1] + SCORE_MATCH_CONSECUTIVE
+          score = math.max(a, b)
+        end
+        D[i][j] = score
+        prev_score = math.max(score, prev_score + gap_score)
+        M[i][j] = prev_score
+      else
+        D[i][j] = SCORE_MIN
+        prev_score = prev_score + gap_score
+        M[i][j] = prev_score
+      end
+    end
+  end
+end
+
+-- Compute a matching score.
+--
+-- Args:
+--   needle (string): must be a subequence of `haystack`, or the result is
+--     undefined.
+--   haystack (string)
+--   case_sensitive (bool, optional): defaults to false
+--
+-- Returns:
+--   number: higher scores indicate better matches. See also `get_score_min`
+--     and `get_score_max`.
+function fzy.score(needle, haystack, case_sensitive)
+  local n = string.len(needle)
+  local m = string.len(haystack)
+
+  if n == 0 or m == 0 or m > MATCH_MAX_LENGTH or n > m then
+    return SCORE_MIN
+  elseif n == m then
+    return SCORE_MAX
+  else
+    local D = {}
+    local M = {}
+    compute(needle, haystack, D, M, case_sensitive)
+    return M[n][m]
+  end
+end
+
+-- Compute the locations where fzy matches a string.
+--
+-- Determine where each character of the `needle` is matched to the `haystack`
+-- in the optimal match.
+--
+-- Args:
+--   needle (string): must be a subequence of `haystack`, or the result is
+--     undefined.
+--   haystack (string)
+--   case_sensitive (bool, optional): defaults to false
+--
+-- Returns:
+--   {int,...}: indices, where `indices[n]` is the location of the `n`th
+--     character of `needle` in `haystack`.
+--   number: the same matching score returned by `score`
+function fzy.positions(needle, haystack, case_sensitive)
+  local n = string.len(needle)
+  local m = string.len(haystack)
+
+  if n == 0 or m == 0 or m > MATCH_MAX_LENGTH or n > m then
+    return {}, SCORE_MIN
+  elseif n == m then
+    local consecutive = {}
+    for i = 1, n do
+      consecutive[i] = i
+    end
+    return consecutive, SCORE_MAX
+  end
+
+  local D = {}
+  local M = {}
+  compute(needle, haystack, D, M, case_sensitive)
+
+  local positions = {}
+  local match_required = false
+  local j = m
+  for i = n, 1, -1 do
+    while j >= 1 do
+      if D[i][j] ~= SCORE_MIN and (match_required or D[i][j] == M[i][j]) then
+        match_required = (i ~= 1) and (j ~= 1) and (
+        M[i][j] == D[i - 1][j - 1] + SCORE_MATCH_CONSECUTIVE)
+        positions[i] = j
+        j = j - 1
+        break
+      else
+        j = j - 1
+      end
+    end
+  end
+
+  return positions, M[n][m]
+end
+
+-- Apply `has_match` and `positions` to an array of haystacks.
+--
+-- Args:
+--   needle (string)
+--   haystack ({string, ...})
+--   case_sensitive (bool, optional): defaults to false
+--
+-- Returns:
+--   {{idx, positions, score}, ...}: an array with one entry per matching line
+--     in `haystacks`, each entry giving the index of the line in `haystacks`
+--     as well as the equivalent to the return value of `positions` for that
+--     line.
+function fzy.filter(needle, haystacks, case_sensitive)
+  local result = {}
+
+  for i, line in ipairs(haystacks) do
+    if fzy.has_match(needle, line, case_sensitive) then
+      local p, s = fzy.positions(needle, line, case_sensitive)
+      table.insert(result, {i, p, s})
+    end
+  end
+
+  return result
+end
+
+-- The lowest value returned by `score`.
+--
+-- In two special cases:
+--  - an empty `needle`, or
+--  - a `needle` or `haystack` larger than than `get_max_length`,
+-- the `score` function will return this exact value, which can be used as a
+-- sentinel. This is the lowest possible score.
+function fzy.get_score_min()
+  return SCORE_MIN
+end
+
+-- The score returned for exact matches. This is the highest possible score.
+function fzy.get_score_max()
+  return SCORE_MAX
+end
+
+-- The maximum size for which `fzy` will evaluate scores.
+function fzy.get_max_length()
+  return MATCH_MAX_LENGTH
+end
+
+-- The minimum score returned for normal matches.
+--
+-- For matches that don't return `get_score_min`, their score will be greater
+-- than than this value.
+function fzy.get_score_floor()
+  return MATCH_MAX_LENGTH * SCORE_GAP_INNER
+end
+
+-- The maximum score for non-exact matches.
+--
+-- For matches that don't return `get_score_max`, their score will be less than
+-- this value.
+function fzy.get_score_ceiling()
+  return MATCH_MAX_LENGTH * SCORE_MATCH_CONSECUTIVE
+end
+
+-- The name of the currently-running implmenetation, "lua" or "native".
+function fzy.get_implementation_name()
+  return "lua"
+end
+
+return fzy

helpers/init.lua

@@ -2,6 +2,7 @@ return {
     client = require(... .. ".client"),
     color = require(... .. ".color"),
     filesystem = require(... .. ".filesystem"),
+    fzy = require(... .. ".fzy"),
     icon_theme = require(... .. ".icon_theme"),
     shape = require(... .. ".shape"),
     time = require(... .. ".time"),

widget/app_launcher/init.lua

@@ -203,6 +203,9 @@ local function build_widget(self)
             end
         end
     end)
+    widget_template:set_search_sort_fn(function(text, a, b)
+        return helpers.fzy.score(text, a.name) > helpers.fzy.score(text, b.name)
+    end)
 
     self._private.widget = awful.popup
     {