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An Emacs dynamic module exposing tree-sitter.
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tree-sitter.el

An Emacs dynamic module exposing tree-sitter.

The package in this repository is relatively inactive. Check out ubolonton/emacs-tree-sitter.

This package requires Emacs 26 or above.

Status

A list of functions and information on whether they have been exposed to Elisp is available in todo.org.

The bindings are relatively plain transfers of the tree-sitter C API. Few, if any, convenience wrappers are provided although some may be added later. That said, the intention is that all types and functions provided by the module should be safe to call and they should not crash Emacs. The values returned by the module are also intended to be garbage collected by Emacs, so no manual memory management functions from tree-sitter will be directly exposed.

The interface to the module is not entirely settled. The bindings may need to change to make them integrate more naturally with Emacs or to fix bugs.

Installation

Building the package requires a few external dependencies. These are included in this repository as Git submodules. To build, first clone the repository and change to the root directory. Then run

make submod
make dist

The first step will recursively initialize the submodules and the second will produce a tar file with the package. Install that in Emacs using package-install-file.

Language grammar

To make any real use of the module you will also need a language grammar for tree-sitter. Several of these are provided by tree-sitter and are listed under its project page. A few of these have packages under the langs/ directory in this repository. To build one of these, change to the directory of that language and run

make submod
make dist

Just like for the binding package, the first step will initialize the submodules, and the second will produce a tar file with the package. Install that with package-install-file in Emacs.

Note: you will first need to run make submod at the root of this repository so that the tree-sitter headers are available.

To package other language grammars you might re-purpose the file for one of these languages to build against a different tree-sitter grammar.

Usage

Once you have the module installed you can load it by requiring tree-sitter. Also be sure to require your language.

(require 'tree-sitter)
(require 'tree-sitter-live)
(require 'tree-sitter-lang-python)

The functions exposed follow the names of their tree-sitter C counterparts, prefixed with tree-sitter rather than ts. For a basic introduction to using tree-sitter see the project documentation.

You can also configure live parsing by first adding your language grammar to tree-sitter-live-auto-alist and then enabling global-tree-sitter-live-mode. For example:

(setq tree-sitter-live-auto-alist
      '((python-mode . tree-sitter-lang-python)))
(global-tree-sitter-live-mode t)

Previewing Trees

Once you have configured tree-sitter-live-mode as above, use command M-x tree-sitter-live-preview to produce a buffer with a preview of a live-parsed tree.

For example the following Python code:

def func(x):
    # Comment
    return 2 + 3

will produce preview output:

module [def func(x):...eturn 2 + 3 ]
  └ function_definition [def func(x):...return 2 + 3]
    ├ def [def]
    ├ identifier [func]
    ├ parameters [(x)]
    │ ├ ( [(]
    │ ├ identifier [x]
    │ └ ) [)]
    ├ : [:]
    ├ comment [# Comment]
    └ return_statement [return 2 + 3]
      ├ return [return]
      └ expression_list [2 + 3]
        └ binary_operator [2 + 3]
          ├ integer [2]
          ├ + [+]
          └ integer [3]

The text in square brackets is an excerpt of the source range covered by a particular tree node.

License

Note that the license, as described below, applies only to the code contained directly within this repository. Code contained within submodules, such as those contained in externals/ directories is licensed separately. Check the license of these other files before using them.

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Please see LICENSE.txt for a copy of the license.

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