mlir-inc-previewer.nvim

A Neovim plugin that previews and manages MLIR .inc files inline — expand the content of a TableGen-generated #include "...inc" directly into your buffer (similar to :r path/to/file.inc, but tag-wrapped and reversible), so you can read the generated declarations without leaving the file.

This is a Lua port of the MLIR Inc Previewer VS Code extension.

Features

• Expand/collapse a single .inc include near the cursor, or expand all in the buffer.
• Macro-aware mode: drops #ifdef/#if ... blocks that are not active given the macros defined in the host file.
• Macro-unaware mode: expands the full .inc content as-is.
• .inc path resolution via the LSP (clangd) first, then a filesystem fallback.
• Expanded blocks are never written to disk (clean-on-save).
• Statusline component showing the number of open preview blocks.

Requirements

• Neovim >= 0.9 (developed/tested on 0.11)
• An LSP such as clangd is recommended for accurate .inc path resolution.

Installation

lazy.nvim / LazyVim:

{
  'ConvolutedDog/mlir-inc-previewer.nvim',
  event = { 'BufReadPre', 'BufNewFile' },
  -- Register commands so lazy loads the plugin (needed for :help too):
  cmd = {
    'MlirIncToggle', 'MlirIncToggleFull', 'MlirIncExpandAll',
    'MlirIncExpandAllFull', 'MlirIncClean', 'MlirIncCleanAndSave',
    'MlirIncNext', 'MlirIncHelp', 'MlirIncRestart',
  },
  opts = {},
}

LazyVim: save the above as ~/.config/nvim/lua/plugins/mlir-inc-previewer.lua.

packer.nvim:

use({
  'ConvolutedDog/mlir-inc-previewer.nvim',
  config = function() require('mlir-inc-previewer').setup() end,
})

Configuration

setup() is optional for the commands, but required to enable keymaps and clean-on-save. Defaults shown below:

require('mlir-inc-previewer').setup({
  -- File extensions the plugin attaches keymaps / clean-on-save to.
  extensions = {
    'c', 'cpp', 'cxx', 'h', 'hpp', 'hxx',   -- standard
    'cc', 'cp', 'c++', 'hh', 'hp', 'h++',   -- variants
    'inl', 'inc', 'ipp', 'tcc', 'tpp',      -- inline / template
    'def',                                  -- definitions
    'cu', 'cuh',                            -- CUDA
  },
  clean_on_save = true,   -- clean preview blocks before :write
  use_lsp = true,         -- resolve .inc paths via the LSP (clangd) when supported
  search_range = 3,       -- look this many lines above/below the cursor for an include
  deep_search = true,     -- last-resort recursive project search (disable on huge repos)
  omit_marker = true,    -- macro-aware: /// summary where code was omitted
  hide_inactive_blocks = false, -- true: drop entire inactive #if..#endif blocks
  keymaps = {
    toggle = '<leader>iu',          -- Expand/Collapse (macro-aware)
    toggle_full = '<leader>ij',     -- Expand/Collapse (macro-unaware)
    expand_all = '<leader>iy',      -- Expand all (macro-aware)
    expand_all_full = '<leader>ih', -- Expand all (macro-unaware)
    clean = '<leader>ic',           -- Clean all preview blocks
    next = '<leader>in',            -- Navigate to next preview block
  },
})

Set any keymap to false or '' to disable it.

Macro-aware inactive blocks — two modes:

Option	Effect
hide_inactive_blocks = true	Entire inactive #ifdef…#endif removed (recommended for MLIR)
omit_marker = true (default, when hide is false)	Keep #ifdef/#endif, insert /// [MLIR_INC_PREVIEW: N lines omitted …]

require('mlir-inc-previewer').setup({ hide_inactive_blocks = true })

Commands

Command	Action
:MlirIncToggle	Expand/Collapse preview near cursor (macro-aware)
:MlirIncToggleFull	Expand/Collapse preview near cursor (macro-unaware)
:MlirIncExpandAll	Expand all previews (macro-aware)
:MlirIncExpandAllFull	Expand all previews (macro-unaware)
:MlirIncClean	Remove all preview blocks
:MlirIncCleanAndSave	Clean all preview blocks, then write the file
:MlirIncNext	Jump to the next preview block
:MlirIncRestart	Restart: clean all previews in every buffer, refresh hooks
:MlirIncHelp	Open plugin help

The cursor does not need to be exactly on the #include line; the plugin searches +/-3 lines around the cursor and also recognises when the cursor is inside an expanded preview block.

Statusline

-- lualine example
sections = {
  lualine_x = { function() return require('mlir-inc-previewer').statusline() end },
}

Testing

A headless smoke test is included:

nvim --headless -u NONE -c "set noswapfile" -c "set rtp+=." -c "luafile scripts/nvim_smoketest.lua"

Performance & resolution notes

• .inc paths are resolved via the LSP only when an attached server actually supports textDocument/definition. If none does (e.g. clangd is not running), no error is shown and a filesystem fallback is used instead. For best accuracy and speed on MLIR projects, run clangd.
• :MlirIncExpandAll builds the whole result in memory and writes the buffer once, so it stays fast even for very large expansions (10k+ lines). The main remaining cost on huge buffers is your LSP/treesitter re-parsing the inserted text, which is outside this plugin's control.
• If the filesystem fallback feels slow on a very large repository, set deep_search = false and rely on the LSP for resolution.

Help

Lazy-loaded plugins are not in &rtp until loaded, so :help mlir-inc-previewer may fail with "no help" if the plugin has not started yet. Use either:

:MlirIncHelp

or load the plugin first, then open help:

:Lazy load mlir-inc-previewer.nvim
:help mlir-inc-previewer

Opening a C/C++ file (or any configured extension) also loads the plugin. Helptags are generated automatically when the plugin starts.

License

MIT — see LICENSE.