feat: fall back to Vim text objects when no treesitter parser available

Author: fecet

lua/wildfire/init.lua

@@ -2,7 +2,16 @@ local api = vim.api
 local keymap = vim.keymap
 local utils = require("wildfire.utils")
 local surround = require("wildfire.surround")
-local ts_select = require("vim.treesitter._select")
+local textobjects = require("wildfire.textobjects")
+
+local ok_tss, ts_select = pcall(require, "vim.treesitter._select")
+if not ok_tss then ts_select = nil end
+
+local function use_treesitter(buf)
+    if not ts_select then return false end
+    local ok, parser = pcall(vim.treesitter.get_parser, buf)
+    return ok and parser ~= nil
+end
 
 local M = {}
 
@@ -57,11 +66,20 @@ local function find_node_at_range(buf, sr, sc, er, ec)
 end
 
 function M.init_selection()
-    local node = vim.treesitter.get_node({ ignore_injections = false })
-    if not node then return end
     local buf = api.nvim_get_current_buf()
     checkpoint:reset(buf)
-    update_selection_by_node(node)
+
+    if use_treesitter(buf) then
+        local node = vim.treesitter.get_node({ ignore_injections = false })
+        if not node then return end
+        update_selection_by_node(node)
+    else
+        local range = textobjects.init()
+        if not range then return end
+        utils.update_selection(buf, range)
+        checkpoint:save(buf, range)
+    end
+
     for _ = 1, vim.v.count1 - 1 do
         M.node_incremental()
     end
@@ -70,33 +88,42 @@ end
 function M.node_incremental()
     local buf = api.nvim_get_current_buf()
 
-    -- Initialize from current visual selection when no prior state
-    if not checkpoint:has_state(buf) then
-        local csrow, cscol, cerow, cecol = utils.visual_selection_range()
-        local ok, parser = pcall(vim.treesitter.get_parser, buf)
-        if not ok or not parser then return end
-        local tree = parser:parse()[1]
-        if not tree then return end
-        local node = tree:root():named_descendant_for_range(csrow - 1, cscol - 1, cerow - 1, cecol)
-        if node then update_selection_by_node(node) end
-        return
-    end
+    if use_treesitter(buf) then
+        -- Initialize from current visual selection when no prior state
+        if not checkpoint:has_state(buf) then
+            local csrow, cscol, cerow, cecol = utils.visual_selection_range()
+            local ok, parser = pcall(vim.treesitter.get_parser, buf)
+            if not ok or not parser then return end
+            local tree = parser:parse()[1]
+            if not tree then return end
+            local node = tree:root():named_descendant_for_range(csrow - 1, cscol - 1, cerow - 1, cecol)
+            if node then update_selection_by_node(node) end
+            return
+        end
 
-    local csrow, cscol, cerow, cecol = utils.visual_selection_range()
-    ts_select.select_parent(1)
-    local nsr, nsc, ner, nec = utils.visual_selection_range()
+        local csrow, cscol, cerow, cecol = utils.visual_selection_range()
+        ts_select.select_parent(1)
+        local nsr, nsc, ner, nec = utils.visual_selection_range()
 
-    -- No change → at tree root
-    if nsr == csrow and nsc == cscol and ner == cerow and nec == cecol then
-        return
-    end
+        -- No change → at tree root
+        if nsr == csrow and nsc == cscol and ner == cerow and nec == cecol then
+            return
+        end
 
-    local node = find_node_at_range(buf, nsr, nsc, ner, nec)
-    if node then
-        update_selection_by_node(node)
+        local node = find_node_at_range(buf, nsr, nsc, ner, nec)
+        if node then
+            update_selection_by_node(node)
+        else
+            utils.update_selection(buf, { nsr, nsc, ner, nec })
+            checkpoint:save(buf, { nsr, nsc, ner, nec })
+        end
     else
-        utils.update_selection(buf, { nsr, nsc, ner, nec })
-        checkpoint:save(buf, { nsr, nsc, ner, nec })
+        local csrow, cscol, cerow, cecol = utils.visual_selection_range()
+        local range = textobjects.expand(buf, csrow, cscol, cerow, cecol)
+        if range then
+            utils.update_selection(buf, range)
+            checkpoint:save(buf, range)
+        end
     end
 end
 

lua/wildfire/textobjects.lua

@@ -0,0 +1,85 @@
+local api = vim.api
+
+local M = {}
+
+local ESC = api.nvim_replace_termcodes("<Esc>", true, true, true)
+
+local CANDIDATES = {
+    "iw", "aw", "iW", "aW",
+    'i"', 'a"', "i'", "a'", "i`", "a`",
+    "i)", "a)", "i]", "a]", "i}", "a}", "i>", "a>",
+    "is", "as", "ip", "ap",
+}
+
+--- Execute one text object from (row, col) and return 1-based {sr, sc, er, ec} or nil.
+---@param obj string
+---@param row integer 1-based
+---@param col integer 1-based
+---@return integer[]|nil
+local function try_textobj(obj, row, col)
+    api.nvim_win_set_cursor(0, { row, col - 1 })
+    pcall(vim.cmd, "normal! v" .. obj)
+    local mode = api.nvim_get_mode().mode
+    if mode ~= "v" then
+        if mode == "V" or mode == "\22" then
+            api.nvim_cmd({ cmd = "normal", bang = true, args = { ESC } }, {})
+        end
+        return nil
+    end
+    local s = vim.fn.getpos("v")
+    local e = vim.fn.getpos(".")
+    api.nvim_cmd({ cmd = "normal", bang = true, args = { ESC } }, {})
+    local sr, sc, er, ec = s[2], s[3], e[2], e[3]
+    if sr > er or (sr == er and sc > ec) then
+        sr, sc, er, ec = er, ec, sr, sc
+    end
+    return { sr, sc, er, ec }
+end
+
+local function strictly_contains(outer, inner)
+    local start_ok = outer[1] < inner[1] or (outer[1] == inner[1] and outer[2] <= inner[2])
+    local end_ok = outer[3] > inner[3] or (outer[3] == inner[3] and outer[4] >= inner[4])
+    local neq = outer[1] ~= inner[1] or outer[2] ~= inner[2] or outer[3] ~= inner[3] or outer[4] ~= inner[4]
+    return start_ok and end_ok and neq
+end
+
+local function range_size(r)
+    return (r[3] - r[1]) * 10000 + (r[4] - r[2])
+end
+
+--- Find the smallest text object range strictly larger than the current selection.
+---@param _buf integer
+---@param sr integer 1-based start row
+---@param sc integer 1-based start col
+---@param er integer 1-based end row
+---@param ec integer 1-based end col
+---@return integer[]|nil
+function M.expand(_buf, sr, sc, er, ec)
+    local current = { sr, sc, er, ec }
+    -- Exit visual mode for text object probing
+    local mode = api.nvim_get_mode().mode
+    if mode == "v" or mode == "V" or mode == "\22" then
+        api.nvim_cmd({ cmd = "normal", bang = true, args = { ESC } }, {})
+    end
+
+    local best, best_size = nil, math.huge
+    for _, obj in ipairs(CANDIDATES) do
+        local range = try_textobj(obj, sr, sc)
+        if range and strictly_contains(range, current) then
+            local s = range_size(range)
+            if s < best_size then
+                best, best_size = range, s
+            end
+        end
+    end
+    return best
+end
+
+--- Select initial text object (iw) at current cursor position.
+---@return integer[]|nil
+function M.init()
+    local pos = api.nvim_win_get_cursor(0)
+    return try_textobj("iw", pos[1], pos[2] + 1)
+end
+
+return M