andrewferrier/debugprint.nvim

github github
debugging
stars 215
issues 14
subscribers 5
forks 13
CREATED

2022-08-08

UPDATED

6 days ago


debugprint.nvim

Test status

Overview

debugprint is a NeoVim plugin that simplifies debugging for those who prefer a low-tech approach. Instead of using a sophisticated debugger like nvim-dap, some people prefer using the 'print' statement to trace the output during execution. With debugprint, you can insert appropriate 'print' statements relevant to the language you're editing. These statements include reference information for quick output navigation and the ability to output variable values.

debugprint supports the following filetypes/programming languages out-of-the-box:

  • bash
  • c
  • cmake
  • cpp (C++)
  • cs (C#)
  • dart
  • dockerfile
  • dosbatch (DOS/Windows Batch)
  • fish
  • fortran
  • go
  • haskell
  • java
  • javascript
  • lean
  • lua
  • make
  • perl
  • php
  • ps1 (Powershell)
  • python
  • r
  • ruby
  • rust
  • sh (sh/Bash)
  • swift
  • typescript
  • vim
  • zsh

It can also be extended to support more.

Features

debugprint is inspired by vim-debugstring, but is updated and refreshed for the NeoVim generation. It has these features:

  • It includes reference information in each 'print line' such as file names, line numbers, a monotonic counter, and snippets of other lines to make it easier to cross-reference them in output.

  • It can output the value of variables (or in some cases, expressions).

  • It dot-repeats.

  • It can detect a variable name under the cursor if it's a supported Treesitter-based language, or will prompt for the variable name with a sensible default if not.

  • In addition to normal mode, it provides keymappings for visual and operator-pending modes, so you can select variables visually and using motions respectively.

  • It provides a command to delete all debugging lines added to the current buffer.

  • It can optionally move to the inserted line (or not).

  • You can add support for languages it doesn't support out of the box.

  • It's MIT Licensed.

Demo

Installation

Requires NeoVim 0.8+.

Optional dependency for NeoVim 0.8: nvim-treesitter. If this is not installed, debugprint will not find variable names under the cursor and will always prompt for a variable name. For NeoVim 0.9+, this dependency is never needed.

Example for lazy.nvim:

return {
    "andrewferrier/debugprint.nvim",
    opts = { … },
    -- Dependency only needed for NeoVim 0.8
    dependencies = {
        "nvim-treesitter/nvim-treesitter"
    },
    -- Remove the following line to use development versions,
    -- not just the formal releases
    version = "*"
}

Example for packer.nvim:

packer.startup(function(use)
    …
    use({
        "andrewferrier/debugprint.nvim",
        config = function()
            opts = { … }
            require("debugprint").setup(opts)
        end,
    })
    …
end)

The sections below detail the allowed options that can appear in the opts object.

Please subscribe to this GitHub issue to be notified of any breaking changes to debugprint.

Keymappings and Commands

By default, the plugin will create some keymappings and commands for use 'out of the box'. There are also some function invocations which are not mapped to any keymappings or commands by default, but could be. This is all shown in the following table.

Mode Default Keymap / Cmd Purpose Lua Function
Normal g?p Insert plain debug line below current line require('debugprint').debugprint()
Normal g?P Insert plain debug line above current line require('debugprint').debugprint({above = true})
Normal g?v Insert variable debug line below current line. If cursor is on a variable, use it, otherwise prompt require('debugprint').debugprint({variable = true})
Normal g?V Insert variable debug line above current line. If cursor is on a variable, use it, otherwise prompt require('debugprint').debugprint({above = true, variable = true})
Normal None Prompt for variable name, insert variable debugging line below the current line require('debugprint').debugprint({ignore_treesitter = true, variable = true})
Normal None Prompt for variable name, insert variable debugging line above the current line require('debugprint').debugprint({ignore_treesitter = true, above = true, variable = true})
Visual g?v Insert visually-selected variable debugging line below the current line require('debugprint').debugprint({variable = true})
Visual g?v Insert visually-selected variable debugging line below the current line require('debugprint').debugprint({variable = true})
Op-pending g?o Locate variable using motion, and insert a variable debugging line below the current line require('debugprint').debugprint({motion = true})
Op-pending g?O Locate variable using motion, and insert a variable debugging line above the current line require('debugprint').debugprint({motion = true, above = true})
Command :DeleteDebugPrints Delete all debug lines added to this buffer require('debugprint').deleteprints()

Custom Keymappings and Commands

The keymappings are chosen specifically because by default they are used to convert sections to ROT-13, which most folks don't use. You can disable the defaults above from being created by setting create_keymaps and/or create_commands, and map them yourself to something else if you prefer:

opts = {
    create_keymaps = false,
    create_commands = false
    ...
}

require("debugprint").setup(opts)

vim.keymap.set("n", "<Leader>d", function()
    -- Note: setting `expr=true` and returning the value are essential
    return require('debugprint').debugprint()
end, {
    expr = true,
})
vim.keymap.set("n", "<Leader>D", function()
    -- Note: setting `expr=true` and returning the value are essential
    return require('debugprint').debugprint({ above = true })
end, {
    expr = true,
})
vim.keymap.set("n", "<Leader>dq", function()
    -- Note: setting `expr=true` and returning the value are essential
    return require('debugprint').debugprint({ variable = true })
end, {
    expr = true,
})
vim.keymap.set("n", "<Leader>Dq", function()
    -- Note: setting `expr=true` and returning the value are essential
    return require('debugprint').debugprint({ above = true, variable = true })
end, {
    expr = true,
})
vim.keymap.set("n", "<Leader>do", function()
    -- Note: setting `expr=true` and returning the value are essential
    -- It's also important to use motion = true for operator-pending motions
    return require('debugprint').debugprint({ motion = true })
end, {
    expr = true,
})

vim.api.nvim_create_user_command("DeleteDebugs", function(opts)
    -- Note: you must set `range=true` and pass through opts for ranges to work
    require('debugprint').deleteprints(opts)
end, {
    range = true})
end)
...

or, to have a keymapping instead for deleting debug lines (this will affect the entire buffer, visual and operator-pending modes will not work):

vim.keymap.set("n", "g?d", function()
    return require('debugprint').deleteprints()
end)

Other Options

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
display_counter true Whether to display/include the monotonically increasing counter in each debug message
display_snippet true Whether to include a snippet of the line above/below in plain debug lines
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
print_tag DEBUGPRINT The string inserted into each print statement, which can be used to uniquely identify statements inserted by debugprint.

Add Custom Filetypes

Note: If you work out a configuration for a filetype not supported out-of-the-box, it would be appreciated if you can open an issue to have it supported out-of-the-box in debugprint so others can benefit. Similarly, if you spot any issues with, or improvements to, the language configurations out-of-the-box, please open an issue also.

If debugprint doesn't support your filetype, you can add it as a custom filetype in one of two ways:

  • In the opts.filetypes object in setup().

  • Using the require('debugprint').add_custom_filetypes() method (designed for use from ftplugin/ directories, etc.

In either case, the format is the same. For example, if adding via setup():

local my_fileformat = {
    left = 'print "',
    right = '"',
    mid_var = "${",
    right_var = '}"',
}

require('debugprint').setup({ filetypes = { ["filetype"] = my_fileformat, ["another_filetype"] = another_of_my_fileformats, ... }})

or add_custom_filetypes():

require('debugprint').add_custom_filetypes({ my_fileformat, ... })

Your new file format will be merged in with those that already exist. If you pass in one that already exists, your configuration will override the built-in configuration.

The keys in the configuration are used like this:

Debug line type Default keys How debug line is constructed
Plain debug line g?p/g?P my_fileformat.left .. "auto-gen DEBUG string" .. my_fileformat.right
Variable debug line g?v/g?V/g?o/g?O my_fileformat.left .. "auto-gen DEBUG string, variable=" .. my_file_format.mid_var .. variable .. my_fileformat.right_var

If it helps to understand these, you can look at the built-in configurations in filetypes.lua.

Feature Comparison with Other Plugins

(This table is quite wide, you may need to scroll horizontally)

Feature debugprint.nvim vim-debugstring printer.nvim refactoring.nvim vim-printer vim-printf logsitter
Print plain debug lines :+1: :+1: :x: :+1: :x: :x: :x:
Print variables using current word/heuristic :+1: :+1: :x: :x: :+1: :+1: :x:
Print variables using treesitter :+1: :x: :x: :+1: :x: :x: :x:
Print variables/expressions using prompts :+1: :+1: :x: :x: :x: :x: :x:
Print variables using motions :+1: :x: :+1: :x: :x: :x: :x:
Print variables using visual mode :+1: :x: :+1: :+1: :+1: :x: :x:
Print debug lines above/below current line :+1: :x: (via global config) :x: :+1: :x: :x:
Supports dot-repeat :+1: :+1: :x: :x: :x: :x: :x:
Can control whether to move to inserted lines :+1: :x: :x: :x: :x: :x: :x:
Command to clean up all debug lines :+1: :x: :x: :x: :x: :x: :x:
Can put debugprint text into default register :x: :x: :+1: :x: :x: :x: :x:
Built-in support for: - - - - - - -
arduino :x: :+1: :x: :x: :x: :x: :x:
bash/sh :+1: :+1: :+1: :x: :+1: :x: :x:
C :+1: :+1: :x: :x: :x: :+1: :x:
C# :+1: :+1: :x: :x: :x: :x: :x:
C++ :+1: :+1: :+1: :+1: :+1: :+1: :x:
CMake :+1: :+1: :x: :x: :x: :x: :x:
dart :+1: :x: :x: :x: :x: :x: :x:
Docker :+1: :+1: :x: :x: :x: :x: :x:
DOS/Windows Batch :+1: :x: :x: :x: :x: :x: :x:
fish :+1: :+1: :x: :x: :x: :x: :x:
Fortran :+1: :+1: :x: :x: :+1: :x: :x:
Golang :+1: :+1: :+1: :+1: :+1: :x: :+1:
Haskell :+1: :+1: :x: :x: :x: :x: :x:
Java :+1: :+1: :+1: :+1: :+1: :x: :x:
Javascript/Typescript :+1: :+1: :+1: :+1: :+1: :x: :+1:
Kotlin :+1: :x: :x: :x: :x: :x: :x:
lean :+1: :x: :x: :x: :x: :x: :x:
lua :+1: :+1: :+1: :+1: :+1: :x: :+1:
GNU Make :+1: :+1: :x: :x: :x: :x: :x:
Perl :+1: :x: :x: :x: :x: :x: :x:
PHP :+1: :+1: :x: :+1: :x: :x: :x:
Powershell/ps1 :+1: :x: :x: :x: :x: :x: :x:
Python :+1: :+1: :+1: :+1: :+1: :x: :x:
R :+1: :x: :x: :x: :x: :x: :x:
Ruby :+1: :+1: :x: :+1: :x: :x: :x:
Rust :+1: :+1: :+1: :x: :+1: :x: :x:
Swift :+1: :x: :x: :x: :x: :x: :x:
VimL (vimscript) :+1: :+1: :+1: :x: :+1: :x: :x:
zsh :+1: :+1: :+1: :x: :+1: :x: :x:
Add custom filetypes (doced/supported) :+1: :x: :+1: :x: :x: :+1: :+1:
Customizable callback formatter :x: :x: :+1: :x: :x: :x: :x:
Implemented in Lua VimL Lua Lua VimL VimL Lua