modules: move textobj to incremental_selection

As suggested in #37, rename the textobj module to incremental_selection.
Also adds a utility function to get the config of a module.

lua/nvim-treesitter/incremental_selection.lua

@@ -0,0 +1,78 @@
+local api = vim.api
+local utils = require'nvim-treesitter.utils'
+local parsers = require'nvim-treesitter.parsers'
+local M = {}
+
+local function node_range_to_vim(node)
+  if not node then return end
+
+  local start_row, start_col, end_row, end_col = node:range()
+
+  local select_range = [[
+  call cursor(%d, %d)
+  normal v
+  call cursor(%d, %d)
+  ]]
+  local exec_command = string.format(select_range,
+    start_row+1, start_col+1,
+    end_row+1, end_col+1)
+
+  api.nvim_exec(exec_command, false)
+end
+
+local function select_incremental(increment_func)
+  return function()
+    local buf, sel_start_line, sel_start_col, _ = unpack(vim.fn.getpos("'<"))
+    local buf, sel_end_line, sel_end_col, _ = unpack(vim.fn.getpos("'>"))
+
+    local node = nil
+    if parsers.has_parser() then
+      local root = parsers.get_parser():parse():root()
+      node = root:named_descendant_for_range(sel_start_line-1, sel_start_col-1, sel_end_line-1, sel_end_col)
+      local node_start_row, node_start_col, node_end_row, node_end_col = node:range()
+
+      if (sel_start_line-1) == node_start_row and (sel_start_col-1) == node_start_col
+        and (sel_end_line-1) == node_end_row and sel_end_col == node_end_col then
+        node = increment_func(node)
+      end
+    end
+
+    return node_range_to_vim(node)
+  end
+end
+
+M.node_incremental = select_incremental(function(node)
+  if node then
+    return node:parent() or node
+  end
+end)
+
+M.scope_incremental = select_incremental(function(node)
+  if node then
+    return utils.smallest_containing_scope(node:parent() or node)
+  end
+end)
+
+function M.attach(bufnr)
+  local buf = bufnr or api.nvim_get_current_buf()
+
+  local config = require'nvim-treesitter.configs'.get_module('incremental_selection')
+  for funcname, mapping in pairs(config.keymaps) do
+    api.nvim_buf_set_keymap(buf, 'v', mapping,
+      string.format(":lua require'nvim-treesitter.incremental_selection'.%s()<CR>", funcname), { silent = true })
+    api.nvim_buf_set_keymap(buf, 'o', mapping,
+      string.format(":normal v%s<CR>", mapping), { silent = true })
+  end
+end
+
+function M.detach(bufnr)
+  local buf = bufnr or api.nvim_get_current_buf()
+
+  local config = require'nvim-treesitter.configs'.get_module('incremental_selection')
+  for _, mapping in pairs(config.keymaps) do
+    api.nvim_buf_del_keymap(buf, 'v', mapping)
+    api.nvim_buf_del_keymap(buf, 'o', mapping)
+  end
+end
+
+return M