initial commit: fork of yorickpeterse/nvim-jump

Fork of https://github.com/yorickpeterse/nvim-jump (MPL-2.0) with one
addition: `label` accepts a table of nvim_set_hl attributes in
addition to a group name, and the plugin re-applies it on ColorScheme.

Upstream declined the feature as out of scope (the project is
considered feature-complete), so it lives here instead. Credit for the
core implementation goes to Yorick Peterse.

Changes relative to upstream:
- Module renamed 'jump' -> 'tiny-jump'
- Namespace and augroup renamed accordingly
- Internal managed highlight group renamed 'JumpLabel' -> 'TinyJumpLabel'
- Default `label` changed from 'FlashLabel' to 'IncSearch' (no longer
  catering to flash.nvim migration)
- README rewritten

lua/tiny-jump/init.lua

@@ -0,0 +1,186 @@
+local fn = vim.fn
+local api = vim.api
+
+local M = {}
+local NS = api.nvim_create_namespace('tiny-jump')
+local CR = api.nvim_replace_termcodes('<Cr>', true, true, true)
+local BS = api.nvim_replace_termcodes('<Bs>', true, true, true)
+local CTRL_H = api.nvim_replace_termcodes('<C-h>', true, true, true)
+local ESC = api.nvim_replace_termcodes('<Esc>', true, true, true)
+local LABELS = {}
+local CONFIG = {
+  -- The labels that may be used, in order of their preference.
+  labels = 'fdsaghjklrewqtyuiopvcxzbnm',
+
+  -- The highlight group to use for match highlights.
+  search = 'Search',
+
+  -- The highlight group to use for labels. May be a group name (string) or
+  -- a table of `nvim_set_hl` attributes.
+  label = 'IncSearch',
+}
+
+local function search(pattern, lines, start_line, matches)
+  local lower = pattern == pattern:lower()
+
+  for idx, line in ipairs(lines) do
+    local lnum = start_line + idx - 1
+    local line = lower and line:lower() or line
+
+    if #line > 0 then
+      local col = 1
+
+      while true do
+        local start, stop = line:find(pattern, col, true)
+
+        if not start then
+          break
+        end
+
+        col = stop + 1
+        table.insert(matches, {
+          line = lnum - 1,
+          start_col = start - 1,
+          end_col = stop,
+          line_index = idx,
+        })
+      end
+    end
+  end
+end
+
+local function available_labels(lines, matches)
+  local avail = {}
+
+  for _, char in ipairs(LABELS) do
+    avail[char] = true
+  end
+
+  -- Disable all the labels that conflict with any of the characters that may be
+  -- matched by the next input.
+  for _, match in ipairs(matches) do
+    local next_col = match.end_col + 1
+    local next_char = lines[match.line_index]:sub(next_col, next_col):lower()
+
+    avail[next_char] = false
+  end
+
+  return avail
+end
+
+function M.start()
+  local win = api.nvim_get_current_win()
+  local buf = api.nvim_win_get_buf(win)
+  local info = fn.getwininfo(win)[1]
+  local top = info.topline
+  local bot = info.botline
+  local lines = api.nvim_buf_get_lines(buf, top - 1, bot, true)
+  local chars = ''
+  local matches = {}
+  local active = {}
+
+  while true do
+    api.nvim_echo({ { '/' .. chars, '' } }, false, {})
+
+    local char = fn.getcharstr(-1)
+    local jump_to = active[char]
+
+    if char == ESC then
+      break
+    elseif char == CR then
+      for _, char in ipairs(LABELS) do
+        jump_to = active[char]
+
+        if jump_to then
+          break
+        end
+      end
+
+      if jump_to then
+        api.nvim_win_set_cursor(win, jump_to)
+      end
+
+      break
+    elseif char == BS or char == CTRL_H then
+      chars = chars:sub(1, #chars - 1)
+    elseif jump_to then
+      api.nvim_win_set_cursor(win, jump_to)
+      break
+    else
+      chars = chars .. char
+    end
+
+    matches = {}
+    active = {}
+    api.nvim_buf_clear_namespace(buf, NS, 0, -1)
+
+    if #chars > 0 then
+      search(chars, lines, top, matches)
+
+      local avail = available_labels(lines, matches)
+
+      for _, match in ipairs(matches) do
+        local label = nil
+
+        for _, cur in ipairs(LABELS) do
+          if avail[cur] then
+            label = cur
+            avail[cur] = false
+            break
+          end
+        end
+
+        vim.hl.range(
+          buf,
+          NS,
+          CONFIG.search,
+          { match.line, match.start_col },
+          { match.line, match.end_col },
+          { priority = 200 }
+        )
+
+        if label then
+          active[label] = { match.line + 1, match.start_col }
+          api.nvim_buf_set_extmark(buf, NS, match.line, match.start_col, {
+            virt_text = { { label, CONFIG.label } },
+            virt_text_pos = 'overlay',
+            priority = 201,
+          })
+        end
+      end
+    end
+
+    vim.cmd.redraw()
+  end
+
+  api.nvim_buf_clear_namespace(buf, NS, 0, -1)
+  api.nvim_echo({ { '', '' } }, false, {})
+  vim.cmd.redraw()
+end
+
+function M.setup(opts)
+  if opts then
+    CONFIG = vim.tbl_extend('force', CONFIG, opts)
+  end
+
+  LABELS = fn.split(CONFIG.labels, '\\zs')
+
+  if type(CONFIG.label) == 'table' then
+    local attrs = CONFIG.label
+    CONFIG.label = 'TinyJumpLabel'
+    -- Apply now (setup may run after the colorscheme is already loaded) and
+    -- on every ColorScheme event (themes clear user-defined highlights).
+    local function apply()
+      api.nvim_set_hl(0, 'TinyJumpLabel', attrs)
+    end
+    apply()
+    api.nvim_create_autocmd('ColorScheme', {
+      group = api.nvim_create_augroup('tiny-jump.highlights', { clear = true }),
+      callback = apply,
+    })
+  end
+end
+
+M.setup()
+
+return M