feat: stable labels

lua/flash/jump.lua

@@ -1,58 +1,12 @@
 local M = {}
 
+---@param label string?
 ---@param state Flash.State
-function M.labels(state)
-  local skip = {} ---@type table<string, boolean>
-  for _, m in ipairs(state.results) do
-    skip[m.next] = true
-  end
-
-  local labels = {} ---@type string[]
-  for _, l in ipairs(vim.split(state.config.labels .. state.config.labels:upper(), "")) do
-    if not skip[l] then
-      labels[#labels + 1] = l
-      skip[l] = true
-    end
-  end
-  return labels
-end
-
----@param state Flash.State
-function M.update(state)
-  ---@type Flash.Match[]
-  local matches = {}
-  vim.list_extend(matches, state.results)
-  -- sort by current win, other win, then by distance
-  table.sort(matches, function(a, b)
-    if a.win ~= b.win then
-      local aw = a.win == state.win and 0 or a.win
-      local bw = b.win == state.win and 0 or b.win
-      return aw < bw
-    end
-    if a.from[1] ~= b.from[1] then
-      if a.win == state.win then
-        local da = math.abs(a.from[1] - state.pos[1])
-        local db = math.abs(b.from[1] - state.pos[1])
-        return da < db
-      end
-      return a.from[1] < b.from[1]
-    end
-    if a.win == state.win then
-      local da = math.abs(a.from[2] - state.pos[2])
-      local db = math.abs(b.from[2] - state.pos[2])
-      return da < db
-    end
-    return a.from[2] < b.from[2]
-  end)
+---@return Flash.Match?
+function M.jump(label, state)
+  ---@type Flash.Match
+  local match
 
-  local labels = M.labels(state)
-  for _, m in ipairs(matches) do
-    -- only label visible matches
-    -- and don't label the first match in the current window
-    if m.visible and not (m.current and m.win == state.win and not state.config.highlight.label_first) then
-      m.label = table.remove(labels, 1)
-      if #labels == 0 then
-        break
       end
     end
   end

lua/flash/labeler.lua

@@ -0,0 +1,108 @@
+---@class Flash.Labeler
+---@field state Flash.State
+---@field used table<string, string>
+local M = {}
+M.__index = M
+
+function M.new(state)
+  local self = setmetatable({}, M)
+  self.state = state
+  self.used = {}
+  return self
+end
+
+function M:update()
+  local labeler = self:labeler()
+  local matches = self:filter()
+  for _, match in ipairs(matches) do
+    if not labeler(match, true) then
+      break
+    end
+  end
+  for _, match in ipairs(matches) do
+    if not labeler(match) then
+      break
+    end
+  end
+end
+
+function M:labeler()
+  local skip = {} ---@type table<string, boolean>
+  for _, m in ipairs(self.state.results) do
+    skip[m.next] = true
+  end
+
+  ---@type table<string, boolean>
+  local available = {}
+  local labels = {} ---@type string[]
+  for _, l in ipairs(vim.split(self.state.config.labels .. self.state.config.labels:upper(), "")) do
+    if not skip[l] then
+      labels[#labels + 1] = l
+      available[l] = true
+      skip[l] = true
+    end
+  end
+
+  ---@param m Flash.Match
+  ---@param used boolean?
+  return function(m, used)
+    if m.label then
+      return true
+    end
+    local pos = table.concat(m.from, ":")
+    local label ---@type string?
+    if used then
+      label = available[self.used[pos]] and self.used[pos] or nil
+    else
+      label = table.remove(labels, 1)
+      while label and not available[label] do
+        label = table.remove(labels, 1)
+      end
+    end
+    if label then
+      self.used[pos] = label
+      m.label = label
+      available[label] = nil
+    end
+    return #labels > 0
+  end
+end
+
+function M:filter()
+  ---@type Flash.Match[]
+  local ret = {}
+
+  -- only label visible matches
+  -- and don't label the first match in the current window
+  for m, match in ipairs(self.state.results) do
+    if match.visible and not (self.state.current == m and not self.state.config.highlight.label_first) then
+      table.insert(ret, match)
+    end
+  end
+
+  -- sort by current win, other win, then by distance
+  table.sort(ret, function(a, b)
+    if a.win ~= b.win then
+      local aw = a.win == self.state.win and 0 or a.win
+      local bw = b.win == self.state.win and 0 or b.win
+      return aw < bw
+    end
+    if a.from[1] ~= b.from[1] then
+      if a.win == self.state.win then
+        local da = math.abs(a.from[1] - self.state.pos[1])
+        local db = math.abs(b.from[1] - self.state.pos[1])
+        return da < db
+      end
+      return a.from[1] < b.from[1]
+    end
+    if a.win == self.state.win then
+      local da = math.abs(a.from[2] - self.state.pos[2])
+      local db = math.abs(b.from[2] - self.state.pos[2])
+      return da < db
+    end
+    return a.from[2] < b.from[2]
+  end)
+  return ret
+end
+
+return M

lua/flash/state.lua

@@ -11,6 +11,8 @@ local Search = require("flash.search")
 ---@field results Flash.Match[]
 ---@field pattern string
 ---@field config Flash.Config
+---@field labels boolean
+---@field labeler Flash.Labeler
 local M = {}
 
 ---@type Flash.State?
@@ -74,11 +76,12 @@ function M.setup()
   })
 end
 
----@param opts? {win:number, op:boolean, config:Flash.Config, wrap:boolean}
+---@param opts? {win:number, op:boolean, config:Flash.Config, wrap:boolean, labels:boolean}
 function M.new(opts)
   opts = opts or {}
   local self = setmetatable({}, { __index = M })
   self.config = Config.get(opts.config)
+  self.labels = opts.labels == nil and true or opts.labels
   self.op = opts.op or false
   self.win = opts.win or vim.api.nvim_get_current_win()
   self.buf = vim.api.nvim_win_get_buf(self.win)
@@ -87,6 +90,7 @@ function M.new(opts)
   self.results = {}
   self.wins = {}
   self.pattern = ""
+  self.labeler = require("flash.labeler").new(self)
   self:update("")
   return self
 end
@@ -143,6 +147,9 @@ function M:update(pattern)
 
   local Jump = require("flash.jump")
   Jump.update(self)
+  if self.labels then
+    self.labeler:update()
+  end
   Highlight.update(self)
   vim.cmd.redraw()
 end