feat: Pick up variable under cursor - closes #2

Author: Andrew Ferrier

README.md

@@ -11,8 +11,10 @@ particular language, to trace the output of a program during execution.
 appropriate to the language being edited, which include the filename/line number
 they are being inserted on, a counter which increases over the duration of a
 NeoVim session each time a statement is generated, as well as optionally
-printing out a variable. `debugprint` comes with the generation logic built in
-for many common programming languages, and can be extended to support more.
+printing out a variable, including automatically picking up an
+identifier/variable name under the cursor. `debugprint` comes with the
+generation logic built in for many common programming languages, and can be
+extended to support more.
 
 `debugprint` is inspired by
 [vim-debugstring](https://github.com/bergercookie/vim-debugstring), which I've
@@ -24,6 +26,8 @@ It provides various improvements:
 
 *   It [dot-repeats](https://jovicailic.org/2018/03/vim-the-dot-command/) with NeoVim.
 
+*   It can pick up a variable name from under the cursor.
+
 *   It indents the lines it inserts more accurately.
 
 *   The output when printing a 'plain' debug line, or a variable, is more
@@ -37,10 +41,18 @@ It provides various improvements:
   <video src="https://user-images.githubusercontent.com/107015/184187236-34f80a31-9626-4a3b-8d03-0f52752781e6.mp4" type="video/mp4"></video>
 </div>
 
+(This demo is not yet updated to show automatically picking up a variable name
+from under the cursor).
+
 ## Installation
 
 **Requires NeoVim 0.7+.**
 
+Optional dependency:
+[nvim-treesitter](https://github.com/nvim-treesitter/nvim-treesitter). If this
+is not installed, `debugprint` will not find variable names under the cursor and
+will always prompt for a variable name.
+
 Example for [`packer.nvim`](https://github.com/wbthomason/packer.nvim):
 
 ```lua
@@ -75,20 +87,23 @@ The sections below detail the allowed options.
 
 ## Keymappings
 
-By default, the plugin will create the following normal-mode keymappings, which
-are the standard way to use it:
+By default, the plugin will create some normal-mode keymappings, which are the
+standard way to use it. There are also some function invocations which are not
+mapped to any keymappings by default, but could be. This is all shown in the
+following table.
 
-| Keymap | Purpose                                                                                              | Equivalent Lua Function                                             |
-| ------ | ---------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------- |
-| `dqp`  | Insert a 'plain' debug line appropriate to the filetype just below the current line                  | `require('debugprint').debugprint()`                                |
-| `dqP`  | The same, but above the current line                                                                 | `require('debugprint').debugprint({above = true})`                  |
-| `dQP`  | Prompt for a variable name, and insert a debugging line just below the current line which outputs it | `require('debugprint').debugprint({variable = true})`               |
-| `dQP`  | The same, but above the current line                                                                 | `require('debugprint').debugprint({above = true, variable = true})` |
+| Keymap          | Purpose                                                                                                                           | Equivalent Lua Function                                                                       |
+| ------          | ----------------------------------------------------------------------------------------------------                              | -------------------------------------------------------------------                           |
+| `dqp`           | Insert a 'plain' debug line appropriate to the filetype just below the current line                                               | `require('debugprint').debugprint()`                                                          |
+| `dqP`           | The same, but above the current line                                                                                              | `require('debugprint').debugprint({above = true})`                                            |
+| `dQP`           | Insert a variable debugging line below the current line. If the cursor is on a variable name, use that, otherwise prompt for one. | `require('debugprint').debugprint({variable = true})`                                         |
+| `dQP`           | The same, but above the current line                                                                                              | `require('debugprint').debugprint({above = true, variable = true})`                           |
+| None by default | Always prompt for a variable name, and insert a debugging line just below the current line which outputs it                       | `require('debugprint').debugprint({ignore_treesitter = true, variable = true})`               |
+| None by default | Always prompt for a variable name, and insert a debugging line just above the current line which outputs it                       | `require('debugprint').debugprint({ignore_treesitter = true, above = true, variable = true})` |
 
 These keybindings are chosen not to conflict with any standard Vim keys (or any
 common plugins, at least that I'm aware of). You can disable them from being
-created by setting `create_keymaps`, and map them yourself to something else if
-you prefer:
+created by setting `create_keymaps`, and map them yourself if you prefer:
 
 ```lua
 opts = {
@@ -115,13 +130,14 @@ end)
 
 ## Other Options
 
-`debugprint` supports the following options in its `opts` object:
+`debugprint` supports the following options in its global `opts` object:
 
-| Option              | Default   | Purpose                                                 |
-| -                   | -         | -                                                       |
-| `create_keymaps`    | `true`    | Creates default keymappings - see above                 |
-| `move_to_debugline` | `false`   | When adding a debug line, moves the cursor to that line |
-| `filetypes`         | See below | Custom filetypes - see below                            |
+| Option              | Default   | Purpose                                                                                                                                      |
+| -                   | -         | -                                                                                                                                            |
+| `create_keymaps`    | `true`    | Creates default keymappings - see above                                                                                                      |
+| `move_to_debugline` | `false`   | When adding a debug line, moves the cursor to that line                                                                                      |
+| `filetypes`         | See below | Custom filetypes - see below                                                                                                                 |
+| `ignore_treesitter` | `false`   | Never use treesitter to find a variable under the cursor, always prompt for it - overrides the same setting on `debugprint()` if set to true |
 
 ## Add Custom Filetypes
 
@@ -201,9 +217,6 @@ If it helps to understand these, you can look at the built-in configurations in
     Markdown)
     ([issue](https://github.com/andrewferrier/debugprint.nvim/issues/9))
 
-*   Using Treesitter to dynamically detect variable names the cursor is on so
-    they don't have to be typed.
-
 ## Known Limitations
 
 *   `debugprint` only supports variable names or simple expressions when using
@@ -216,8 +229,7 @@ If it helps to understand these, you can look at the built-in configurations in
 
 *   [refactoring.nvim](https://github.com/ThePrimeagen/refactoring.nvim) -
     similar capabilities to debugprint, supports a slighter smaller set of
-    languages. Can pick up treesitter identifiers as variables and remove
-    added statements - these are on the debugprint roadmap.
+    languages. Can remove added statement - this is on the debugprint roadmap.
 
 *   [logsitter](https://github.com/gaelph/logsitter.nvim) - supports a smaller
     set of languages and requires you to set up your own autocmds/keymappings.

lua/debugprint/init.lua

@@ -5,12 +5,14 @@ local opts
 OPTION_DEFAULTS = {
     create_keymaps = true,
     move_to_debugline = false,
+    ignore_treesitter = false,
     filetypes = require("debugprint.filetypes"),
 }
 
 FUNCTION_OPTION_DEFAULTS = {
     above = false,
     variable = false,
+    ignore_treesitter = false,
 }
 
 local counter = 0
@@ -60,6 +62,31 @@ local indent_line = function(current_line)
     end
 end
 
+local find_treesitter_variable = function()
+    local function requiref(module)
+        require(module)
+    end
+
+    local ts_utils_test = pcall(requiref, "nvim-treesitter.ts_utils")
+
+    if not ts_utils_test then
+        return nil
+    else
+        local ts_utils = require("nvim-treesitter.ts_utils")
+        -- Once get_node_at_cursor() is in NeoVim core, the nvim-treesitter
+        -- dependency can be removed: https://github.com/neovim/neovim/pull/18232
+        local node = ts_utils.get_node_at_cursor()
+        local node_type = node:type()
+        local variable_name = vim.treesitter.query.get_node_text(node, 0)
+
+        if node_type ~= "identifier" then
+            return nil
+        else
+            return variable_name
+        end
+    end
+end
+
 local debugprint_logic = function(funcopts)
     local current_line = vim.api.nvim_win_get_cursor(0)[1]
     local filetype = vim.api.nvim_get_option_value(
@@ -119,7 +146,16 @@ local debugprint_cache = function(o)
         end
 
         if o.variable == true then
-            o.variable_name = vim.fn.input("Variable name: ")
+            if
+                o.ignore_treesitter ~= true
+                and opts.ignore_treesitter ~= true
+            then
+                o.variable_name = find_treesitter_variable()
+            end
+
+            if o.variable_name == nil then
+                o.variable_name = vim.fn.input("Variable name: ")
+            end
         end
 
         cache_request = o
@@ -146,6 +182,7 @@ M.debugprint = function(o)
     vim.validate({
         above = { funcopts.above, "boolean" },
         variable = { funcopts.above, "boolean" },
+        ignore_treesitter = { funcopts.ignore_treesitter, "boolean" },
     })
 
     funcopts.prerepeat = true

tests/debugprint.lua

@@ -35,7 +35,7 @@ end)
 
 describe("can do basic debug statement insertion", function()
     before_each(function()
-        debugprint.setup()
+        debugprint.setup({ ignore_treesitter = true })
     end)
 
     it("can insert a basic statement below", function()
@@ -111,7 +111,7 @@ end)
 
 describe("can do variable debug statement insertion", function()
     before_each(function()
-        debugprint.setup()
+        debugprint.setup({ ignore_treesitter = true })
     end)
 
     it("can insert a variable statement below", function()
@@ -155,7 +155,7 @@ end)
 
 describe("can do various file types", function()
     before_each(function()
-        debugprint.setup()
+        debugprint.setup({ ignore_treesitter = true })
     end)
 
     it("can handle a .vim file", function()
@@ -235,7 +235,7 @@ end)
 
 describe("can do indenting correctly", function()
     before_each(function()
-        debugprint.setup()
+        debugprint.setup({ ignore_treesitter = true })
     end)
 
     it("lua - inside function", function()
@@ -315,6 +315,7 @@ end)
 describe("add custom filetype with setup()", function()
     before_each(function()
         debugprint.setup({
+            ignore_treesitter = true,
             filetypes = {
                 ["wibble"] = {
                     left = "foo('",
@@ -366,7 +367,7 @@ end)
 
 describe("add custom filetype with add_custom_filetypes()", function()
     before_each(function()
-        debugprint.setup()
+        debugprint.setup({ ignore_treesitter = true })
 
         vim.api.nvim_set_option_value("expandtab", true, {})
         vim.api.nvim_set_option_value("shiftwidth", 4, {})
@@ -405,7 +406,10 @@ describe("move to new line", function()
     end)
 
     it("true below", function()
-        debugprint.setup({ move_to_debugline = true })
+        debugprint.setup({
+            ignore_treesitter = true,
+            move_to_debugline = true,
+        })
 
         set_lines({
             "foo",
@@ -426,7 +430,10 @@ describe("move to new line", function()
     end)
 
     it("true above", function()
-        debugprint.setup({ move_to_debugline = true })
+        debugprint.setup({
+            ignore_treesitter = true,
+            move_to_debugline = true,
+        })
 
         set_lines({
             "foo",
@@ -447,7 +454,10 @@ describe("move to new line", function()
     end)
 
     it("false", function()
-        debugprint.setup({ move_to_debugline = false })
+        debugprint.setup({
+            ignore_treesitter = true,
+            move_to_debugline = false,
+        })
 
         set_lines({
             "foo",
@@ -470,7 +480,10 @@ end)
 
 describe("can repeat", function()
     before_each(function()
-        debugprint.setup()
+        debugprint.setup({
+            ignore_treesitter = true,
+            ignore_treesitter = true,
+        })
     end)
 
     it("can insert a basic statement and repeat", function()
@@ -571,7 +584,10 @@ end)
 
 describe("can repeat with move to line", function()
     it("true below", function()
-        debugprint.setup({ move_to_debugline = true })
+        debugprint.setup({
+            ignore_treesitter = true,
+            move_to_debugline = true,
+        })
 
         set_lines({
             "foo",
@@ -593,3 +609,86 @@ describe("can repeat with move to line", function()
         assert.are.same(vim.api.nvim_win_get_cursor(0), { 3, 0 })
     end)
 end)
+
+describe("can handle treesitter identifiers", function()
+    it("standard", function()
+        debugprint.setup({})
+
+        set_lines({
+            "function x() {",
+            "local xyz = 3",
+            "end",
+        })
+
+        local filename = write_file("lua")
+        vim.api.nvim_win_set_cursor(0, { 2, 6 })
+        feedkeys("dQp")
+
+        check_lines({
+            "function x() {",
+            "local xyz = 3",
+            "print('DEBUG[1]: " .. filename .. ":2: xyz=' .. vim.inspect(xyz))",
+            "end",
+        })
+
+        assert.are.same(vim.api.nvim_win_get_cursor(0), { 2, 6 })
+    end)
+
+    it("non-identifier", function()
+        debugprint.setup({})
+
+        set_lines({
+            "function x() {",
+            "local xyz = 3",
+            "end",
+        })
+
+        local filename = write_file("lua")
+        vim.api.nvim_win_set_cursor(0, { 2, 6 })
+        feedkeys("dQpapple<CR>")
+
+        check_lines({
+            "function x() {",
+            "local xyz = 3",
+            "print('DEBUG[1]: "
+                .. filename
+                .. ":2: apple=' .. vim.inspect(apple))",
+            "end",
+        })
+
+        assert.are.same(vim.api.nvim_win_get_cursor(0), { 2, 6 })
+    end)
+
+    it("disabled at function level", function()
+        debugprint.setup({})
+
+        set_lines({
+            "function x() {",
+            "local xyz = 3",
+            "end",
+        })
+
+        local filename = write_file("lua")
+        vim.api.nvim_win_set_cursor(0, { 2, 6 })
+        vim.keymap.set("n", "zxa", function()
+            return require("debugprint").debugprint({
+                variable = true,
+                ignore_treesitter = true,
+            })
+        end, {
+            expr = true,
+        })
+        feedkeys("zxaapple<CR>")
+
+        check_lines({
+            "function x() {",
+            "local xyz = 3",
+            "print('DEBUG[1]: "
+                .. filename
+                .. ":2: apple=' .. vim.inspect(apple))",
+            "end",
+        })
+
+        assert.are.same(vim.api.nvim_win_get_cursor(0), { 2, 6 })
+    end)
+end)