From a478bf936b2a648312704c02898eb7e5bfbf5692 Mon Sep 17 00:00:00 2001
From: Jongwook Choi <wookayin@gmail.com>
Date: Thu, 1 Feb 2024 15:34:35 -0500
Subject: [PATCH] feat(treesitter): use 0-based indexing to show ranges in
 `:InspectTree`

Problem:

- `:InspectTree` was showing node ranges in 1-based indexing, i.e., in
  vim cursor position (lnum, col). However, treesitter API adopts
  0-based indexing to represent ranges (Range4). This can often be
  confusing for developers and plugin authors when debugging code
  written with treesiter APIs.

Solution:

- Change to 0-based indexing from 1-based indexing to show node ranges
  in `:InspectTree`.

- Note: To make things not complicated, we do not provide an option or
  keymap to configure which indexing mode to use.
---
 runtime/doc/news.txt               |  2 ++
 runtime/lua/vim/treesitter/dev.lua | 29 +++++++++++++++--------------
 2 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/runtime/doc/news.txt b/runtime/doc/news.txt
index e83fc25f88..c1fc04d9cf 100644
--- a/runtime/doc/news.txt
+++ b/runtime/doc/news.txt
@@ -224,6 +224,8 @@ The following new APIs and features were added.
   • |vim.treesitter.query.edit()| allows live editing of treesitter
     queries.
   • Improved error messages for query parsing.
+  • `:InspectTree` (|vim.treesitter.inspect_tree()|) shows node ranges in
+    0-based indexing instead of 1-based indexing.
 
 • |vim.ui.open()| opens URIs using the system default handler (macOS `open`,
   Windows `explorer`, Linux `xdg-open`, etc.)
diff --git a/runtime/lua/vim/treesitter/dev.lua b/runtime/lua/vim/treesitter/dev.lua
index 1385642acd..e1f93a654b 100644
--- a/runtime/lua/vim/treesitter/dev.lua
+++ b/runtime/lua/vim/treesitter/dev.lua
@@ -3,16 +3,20 @@ local api = vim.api
 ---@class TSDevModule
 local M = {}
 
+---@private
 ---@class TSTreeView
 ---@field ns integer API namespace
----@field opts table Options table with the following keys:
----                  - anon (boolean): If true, display anonymous nodes
----                  - lang (boolean): If true, display the language alongside each node
----                  - indent (number): Number of spaces to indent nested lines. Default is 2.
+---@field opts TSTreeViewOpts
 ---@field nodes TSP.Node[]
 ---@field named TSP.Node[]
 local TSTreeView = {}
 
+---@private
+---@class TSTreeViewOpts
+---@field anon boolean If true, display anonymous nodes.
+---@field lang boolean If true, display the language alongside each node.
+---@field indent number Number of spaces to indent nested lines.
+
 ---@class TSP.Node
 ---@field node TSNode Treesitter node
 ---@field field string? Node field
@@ -115,6 +119,7 @@ function TSTreeView:new(bufnr, lang)
     ns = api.nvim_create_namespace('treesitter/dev-inspect'),
     nodes = nodes,
     named = named,
+    ---@type TSTreeViewOpts
     opts = {
       anon = false,
       lang = false,
@@ -129,16 +134,12 @@ end
 
 local decor_ns = api.nvim_create_namespace('ts.dev')
 
----@param lnum integer
----@param col integer
----@param end_lnum integer
----@param end_col integer
+---@param range Range4
 ---@return string
-local function get_range_str(lnum, col, end_lnum, end_col)
-  if lnum == end_lnum then
-    return string.format('[%d:%d - %d]', lnum + 1, col + 1, end_col)
-  end
-  return string.format('[%d:%d - %d:%d]', lnum + 1, col + 1, end_lnum + 1, end_col)
+local function range_to_string(range)
+  ---@type integer, integer, integer, integer
+  local row, col, end_row, end_col = unpack(range)
+  return string.format('[%d, %d] - [%d, %d]', row, col, end_row, end_col)
 end
 
 ---@param w integer
@@ -212,7 +213,7 @@ function TSTreeView:draw(bufnr)
   local lang_hl_marks = {} ---@type table[]
 
   for i, item in self:iter() do
-    local range_str = get_range_str(item.node:range())
+    local range_str = range_to_string({ item.node:range() })
     local lang_str = self.opts.lang and string.format(' %s', item.lang) or ''
 
     local text ---@type string