From b065423013c35112f00154b575900482738ec7ef Mon Sep 17 00:00:00 2001
From: Brian Ryall <bryall@users.noreply.github.com>
Date: Sun, 6 Sep 2020 22:48:36 -0400
Subject: [PATCH] added treesitter builtin (#31)

* added treesitter builtim

* fixed treesitter pr comments

* fix the buffer previewer to keep lnum visable
---
 lua/telescope/builtin.lua    | 56 ++++++++++++++++++++++++++++++++++++
 lua/telescope/make_entry.lua | 25 ++++++++++++++++
 lua/telescope/previewers.lua |  2 ++
 3 files changed, 83 insertions(+)

diff --git a/lua/telescope/builtin.lua b/lua/telescope/builtin.lua
index 8cf6906..4eae327 100644
--- a/lua/telescope/builtin.lua
+++ b/lua/telescope/builtin.lua
@@ -370,4 +370,60 @@ builtin.buffers = function(opts)
   }):find()
 end
 
+local function prepare_match(entry, kind)
+  local entries = {}
+
+  if entry.node then
+      entry["kind"] = kind
+      table.insert(entries, entry)
+  else
+    for name, item in pairs(entry) do
+        vim.list_extend(entries, prepare_match(item, name))
+    end
+  end
+
+  return entries
+end
+
+builtin.treesitter = function(opts)
+  opts = opts or {}
+
+  local has_nvim_treesitter, nvim_treesitter = pcall(require, 'nvim-treesitter')
+  if not has_nvim_treesitter then
+    print('You need to install nvim-treesitter')
+    return
+  end
+
+  local parsers = require('nvim-treesitter.parsers')
+  if not parsers.has_parser() then
+    print('No parser for the current buffer')
+    return
+  end
+
+  local ts_locals = require('nvim-treesitter.locals')
+  local bufnr = opts.bufnr or vim.api.nvim_get_current_buf()
+
+  local results = {}
+  for _, definitions in ipairs(ts_locals.get_definitions(bufnr)) do
+    local entries = prepare_match(definitions)
+    for _, entry in ipairs(entries) do
+      table.insert(results, entry)
+    end
+  end
+
+  if vim.tbl_isempty(results) then
+    return
+  end
+
+  pickers.new(opts, {
+    prompt    = 'Treesitter Symbols',
+    finder    = finders.new_table {
+      results = results,
+      entry_maker = make_entry.gen_from_treesitter(opts)
+    },
+    previewer = previewers.vim_buffer.new(opts),
+    sorter    = sorters.get_norcalli_sorter(),
+  }):find()
+end
+
 return builtin
diff --git a/lua/telescope/make_entry.lua b/lua/telescope/make_entry.lua
index 7c35699..a25758e 100644
--- a/lua/telescope/make_entry.lua
+++ b/lua/telescope/make_entry.lua
@@ -191,4 +191,29 @@ function make_entry.gen_from_buffer(opts)
   end
 end
 
+function make_entry.gen_from_treesitter(opts)
+  opts = opts or {}
+  return function(entry)
+    local ts_utils = require('nvim-treesitter.ts_utils')
+    local start_row, start_col, end_row, end_col = ts_utils.get_node_range(entry.node)
+    local node_text = ts_utils.get_node_text(entry.node)[1]
+    local bufnr = vim.api.nvim_get_current_buf()
+    return {
+      valid = true,
+
+      value = entry.node,
+      ordinal = entry.kind .. " " .. node_text,
+      display = entry.kind .. " " .. node_text,
+
+      filename = vim.api.nvim_buf_get_name(bufnr),
+      -- need to add one since the previewer substacts one
+      lnum = start_row + 1,
+      col = start_col,
+      text = node_text,
+      start = start_row,
+      finish = end_row
+    }
+  end
+end
+
 return make_entry
diff --git a/lua/telescope/previewers.lua b/lua/telescope/previewers.lua
index 2978e03..493a2f6 100644
--- a/lua/telescope/previewers.lua
+++ b/lua/telescope/previewers.lua
@@ -123,6 +123,8 @@ previewers.vim_buffer = defaulter(function(_)
 
       if entry.lnum then
         vim.api.nvim_buf_add_highlight(bufnr, previewer_ns, "Visual", entry.lnum - 1, 0, -1)
+        vim.api.nvim_win_set_option(status.preview_win, 'scrolloff', 10)
+        vim.api.nvim_win_set_cursor(status.preview_win, {entry.lnum, 0})
         -- print("LNUM:", entry.lnum)
       end
     end,