Skip to main content

​
get_available(tier)

Return a list of languages available for installation from the parser manifest.

​
Parameters

​
tier
integer
Filter parsers by tier. Valid values:
  • 1 - stable parsers
  • 2 - unstable parsers
  • 3 - unmaintained parsers
  • 4 - unsupported parsers
If omitted, returns parsers from all tiers.

​
Returns

​
languages
string[]
Array of language names available for installation, sorted alphabetically.

​
Usage

-- Get all available parsers
local all_parsers = require('nvim-treesitter').get_available()
print(vim.inspect(all_parsers))
-- { "bash", "c", "lua", "python", "rust", ... }

-- Get only stable parsers
local stable = require('nvim-treesitter').get_available(1)

-- Get unstable parsers
local unstable = require('nvim-treesitter').get_available(2)

​
Implementation Notes

  • Triggers the User TSUpdate autocommand to allow dynamic parser registration
  • Reads from the parser manifest (nvim-treesitter.parsers module)
  • Results are always sorted alphabetically

​
get_installed(type)

Return a list of languages installed via nvim-treesitter.
This only searches nvim-treesitter’s configured installation directory. Parsers from other sources placed elsewhere on runtimepath are not included.

​
Parameters

​
type
'queries'|'parsers'
Filter installed languages by type:
  • "parsers" - only show languages with installed parsers
  • "queries" - only show languages with installed queries
If omitted, returns languages that have either parsers or queries installed.

​
Returns

​
languages
string[]
Array of installed language names.

​
Usage

-- Get all installed languages (parsers and/or queries)
local installed = require('nvim-treesitter').get_installed()
print(vim.inspect(installed))
-- { "lua", "python", "rust", ... }

-- Get only languages with installed parsers
local parsers = require('nvim-treesitter').get_installed('parsers')

-- Get only languages with installed queries
local queries = require('nvim-treesitter').get_installed('queries')

​
List All Parsers (Any Source)

To list all parsers installed from any source (not just nvim-treesitter): 
local all_parsers = vim.api.nvim_get_runtime_file('parser/*', true)
for _, parser in ipairs(all_parsers) do
  print(parser)
end

​
Implementation Details

The function:
  1. Scans the queries/ directory for query folders (unless type = 'parsers')
  2. Scans the parser/ directory for .so files (unless type = 'queries')
  3. Returns unique language names found in either location
A language may have queries without a parser (queries only) or a parser without queries (parser only). Calling without the type parameter returns both.

​
indentexpr()

Used to enable treesitter-based indentation for a language. This function should be assigned to the indentexpr option.
This function is specifically designed to be called as Vimscript’s indentexpr and has a special calling convention. It reads from vim.v.lnum internally.

​
Parameters

None. The function reads the line number from vim.v.lnum (set by Neovim when evaluating indentexpr).

​
Returns

​
indent
integer
The calculated indentation level in columns for the current line.Special return values:
  • -1 - use autoindent (fall back to cindent or smartindent)
  • 0 - no indentation
  • positive integer - specific column position for indentation

​
Usage

Enable treesitter indentation in your configuration: 
-- In init.lua or filetype plugin
vim.api.nvim_create_autocmd('FileType', {
  pattern = { 'rust', 'javascript', 'python' },
  callback = function()
    vim.bo.indentexpr = "v:lua.require'nvim-treesitter'.indentexpr()"
  end,
})
Or in a specific filetype plugin (e.g., ~/.config/nvim/after/ftplugin/rust.lua): 
vim.bo.indentexpr = "v:lua.require'nvim-treesitter'.indentexpr()"

​
How It Works

  1. Gets the current buffer’s treesitter parser
  2. Parses the visible window range for performance
  3. Finds the language tree covering the current line
  4. Queries indent captures from the language’s indents.scm query file
  5. Calculates indentation based on treesitter node hierarchy and indent directives

​
Indent Query Captures

The function recognizes these captures in indents.scm:
  • @indent.begin - increase indent for child nodes
  • @indent.end - decrease indent
  • @indent.align - align with specific delimiter
  • @indent.dedent - dedent current line
  • @indent.branch - conditional indent based on branch
  • @indent.ignore - preserve existing indentation
  • @indent.auto - use autoindent
  • @indent.zero - force zero indentation

​
Performance Considerations

  • Only parses the visible window range (lines between w0 and w$)
  • Uses memoization to cache indent query results per buffer and syntax tree
  • Ignores comment parsers to avoid incorrect indentation in documentation

​
Limitations

  • Requires a indents.scm query file for the language
  • Returns -1 (fallback to autoindent) if no parser or query is available
  • May not work correctly in injected language regions with complex nesting

​
Example Configuration

Complete setup with treesitter features: 
vim.api.nvim_create_autocmd('FileType', {
  pattern = { 'rust', 'lua', 'python' },
  callback = function()
    -- Syntax highlighting (Neovim core)
    vim.treesitter.start()
    
    -- Folds (Neovim core)
    vim.wo.foldexpr = 'v:lua.vim.treesitter.foldexpr()'
    vim.wo.foldmethod = 'expr'
    
    -- Indentation (nvim-treesitter)
    vim.bo.indentexpr = "v:lua.require'nvim-treesitter'.indentexpr()"
  end,
})

​
See Also