add examples

examples/text-objects.lua

@@ -0,0 +1,126 @@
+local utils = require 'u.utils'
+local Pos = require 'u.pos'
+local Range = require 'u.range'
+local Buffer = require 'u.buffer'
+
+local M = {}
+
+function M.setup()
+  -- Select whole file:
+  utils.define_text_object('ag', function() return Buffer.current():all() end)
+
+  -- Select current line:
+  utils.define_text_object('a.', function()
+    local lnum = Pos.from_pos('.').lnum
+    return Buffer.current():line0(lnum)
+  end)
+
+  -- Select the nearest quote:
+  utils.define_text_object('aq', function() return Range.find_nearest_quotes() end)
+  utils.define_text_object('iq', function()
+    local range = Range.find_nearest_quotes()
+    if range == nil then return end
+    return range:shrink(1)
+  end)
+
+  ---Selects the next quote object (searches forward)
+  ---@param q string
+  local function define_quote_obj(q)
+    local function select_around()
+      -- Operator mappings are effectively running in visual mode, the way
+      -- `define_text_object` is implemented, so feed the keys `a${q}` to vim
+      -- to select the appropriate text-object
+      vim.cmd { cmd = 'normal', args = { 'a' .. q }, bang = true }
+
+      -- Now check on the visually selected text:
+      local range = Range.from_vtext()
+      if range:is_empty() then return range.start end
+      range.start = range.start:find_next(1, q) or range.start
+      range.stop = range.stop:find_next(-1, q) or range.stop
+      return range
+    end
+
+    utils.define_text_object('a' .. q, function() return select_around() end)
+    utils.define_text_object('i' .. q, function()
+      local range_or_pos = select_around()
+      if Range.is(range_or_pos) then
+        local start_next = range_or_pos.start:next(1)
+        local stop_prev = range_or_pos.stop:next(-1)
+        if start_next > stop_prev then return start_next end
+
+        local range = range_or_pos:shrink(1)
+        return range
+      else
+        return range_or_pos
+      end
+    end)
+  end
+  define_quote_obj [["]]
+  define_quote_obj [[']]
+  define_quote_obj [[`]]
+
+  ---Selects the "last" quote object (searches backward)
+  ---@param q string
+  local function define_last_quote_obj(q)
+    local function select_around()
+      local curr = Pos.from_pos('.'):find_next(-1, q)
+      if not curr then return end
+      -- Reset visual selection to current context:
+      Range.new(curr, curr):set_visual_selection()
+      vim.cmd.normal('a' .. q)
+      local range = Range.from_vtext()
+      if range:is_empty() then return range.start end
+      range.start = range.start:find_next(1, q) or range.start
+      range.stop = range.stop:find_next(-1, q) or range.stop
+      return range
+    end
+
+    utils.define_text_object('al' .. q, function() return select_around() end)
+    utils.define_text_object('il' .. q, function()
+      local range_or_pos = select_around()
+      if range_or_pos == nil then return end
+
+      if Range.is(range_or_pos) then
+        local start_next = range_or_pos.start:next(1)
+        local stop_prev = range_or_pos.stop:next(-1)
+        if start_next > stop_prev then return start_next end
+
+        local range = range_or_pos:shrink(1)
+        return range
+      else
+        return range_or_pos
+      end
+    end)
+  end
+  define_last_quote_obj [["]]
+  define_last_quote_obj [[']]
+  define_last_quote_obj [[`]]
+
+  -- Selects the "last" bracket object (searches backward):
+  local function define_last_bracket_obj(b, ...)
+    local function select_around()
+      local curr = Pos.from_pos('.'):find_next(-1, b)
+      if not curr then return end
+
+      local other = curr:find_match(1000)
+      if not other then return end
+
+      return Range.new(curr, other)
+    end
+
+    local keybinds = { ... }
+    table.insert(keybinds, b)
+    for _, k in ipairs(keybinds) do
+      utils.define_text_object('al' .. k, function() return select_around() end)
+      utils.define_text_object('il' .. k, function()
+        local range = select_around()
+        return range and range:shrink(1)
+      end)
+    end
+  end
+  define_last_bracket_obj('}', 'B')
+  define_last_bracket_obj ']'
+  define_last_bracket_obj(')', 'b')
+  define_last_bracket_obj '>'
+end
+return M