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tree-hugger

Mine source code repositories at scale. Easily. Tree-hugger is a light-weight, high level library which provides Pythonic APIs to mine trough Git repositories (it works on any collection of supported code files, actually).

Tree-hugger is built on top of tree-sitter.

Covered languages:

• Python
• PHP
• Java
• JavaScript
• C++

System Requirement: Python 3.6

Contributors

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Contents

Installation

From pip:

pip install -U tree-hugger PyYAML

From Source:

git clone https://github.com/autosoft-dev/tree-hugger.git

cd tree-hugger

pip install -e .

The installation process is tested in macOS Mojave, we have a separate docker binding for compiling the libraries for Linux and soon this library will be integrated in that as well

You may need to install libgit2. In case you are in mac just use brew install libgit2

Setup

Getting your .so files

Update - 19.11.2021 -

We are not able to support the s3 based download anymore. So the download_libs command does not work. We are making them available via this release - https://github.com/autosoft-dev/tree-hugger/releases/tag/0.10.1 Please download the required zip file from there.

Please note that building the libraries has been tested under a macOS Mojave with Apple LLVM version 10.0.1 (clang-1001.0.46.4). However, they should work on all main stream Linux systems. We have not tested them on Windows.

Environment variables

You can set up TS_LIB_PATH environment variable for the tree-sitter lib path (the .so files you just donwloaded) and then the libary will use them automatically. Otherwise, as an alternative, you can pass it when creating any Parser object.

Hello world example

1. Generate the librairies : run the above command to generate the libraries.

   In our settings we use the -c flag to copy the generated tree-sitter library's .so file to our workspace. Once copied, we place it under a directory called tslibs (It is in the .gitignore).

   ⚠ If you are using linux,you will need to use our tree-sitter-docker image and manually copy the final .so file. Unless you are in a debian based distro and in that case you should probably use our pre-compiled version via download_libs command as described above

2. Setup environment variable (optional) Assuming that you have the necessary environment variable setup. The following line of code will create a Parser object according to the language you want to analyse:

Python

# Python
from tree_hugger.core import PythonParser
pp = PythonParser()
pp.parse_file("tests/assets/file_with_different_functions.py")
pp.get_all_function_names()
Out[4]:
['first_child', 'second_child', 'say_whee', 'wrapper', 'my_decorator', 'parent']

PHP

# PHP
from tree_hugger.core import PHPParser
phpp = PHPParser()
phpp.parse_file("tests/assets/file_with_different_functions.php")
phpp.get_all_function_names() 
Out[5] :
['foo', 'test', 'simple_params', 'variadic_param' ]

Java

# Java 
from tree_hugger.core import JavaParser
jp = JavaParser()
jp.parse_file("tests/assets/file_with_different_methods.java")
jp.get_all_class_names() 
Out[6] :
['HelloWorld','Animal', 'Dog' ]

JavaScript

# JavaScript
from tree_hugger.core import JavascriptParser
jsp = JavascriptParser()
jsp.parse_file("tests/assets/file_with_different_functions.js")
jsp.get_all_function_names() 
Out[7] :
['test', 'utf8_to_b64',	'sum', 'multiply' ]

C++

from tree_hugger.core import CPPParser
cp = CPPParser()
cp.parse_file("tests/assets/file_with_different_functions.cpp")
cp.get_all_function_names() 
Out[8] :
['foo', 'test', 'simple_params', 'variadic_param' ]

API reference

Extending tree-hugger

Extending tree-hugger for other languages and/or more functionalities for the already provided ones, is easy.

1. Adding languages:

Parsed languages can be extended through adding a parser class from the BaseParser class. The only mandatory argument that a Parser class should pass to the parent is the language. This is a string. Such as python (lower case). Each parser class must have the options to take in the path of the tree-sitter library (.so file that we are using to parse the code) and the path to the queries yaml file, in their constructor.

The BaseParser class can do few things:

• Loading and preparing the .so file with respect to the language you just mentioned.
• Loading, preparing and parsing the query yaml file. (for the queries, we internally use an extended UserDict class)
• Providing an API to parse a file and prepare it for query. BaseParser.parse_file

It also gives you another (most likely not to be exposed outside) API _run_query_and_get_captures which lets you run any queries and return back the matched results (if any) from the parsed tree.

We use those APIs once we have called parse_file and parsed the file.

2. Adding queries:

Queries processed on source code are s-expressions, they are listed in a queries.ymlfile for each parser class. Tree-hugger gives you a way to write your queries in yaml file for each language parsed.

Query structure: A name of a query followed by the query itself. Written as an s-expression. Example:

all_function_docstrings:
        "
        (
            function_definition
            name: (identifier) @function.def
            body: (block(expression_statement(string))) @function.docstring
        )
        "

You have to follow yaml grammar while writing these queries. You can see a bit more about writng these queries in the documentation of tree-sitter.

Some example queries, that you will find in the yaml file (and their corresponding API from the PythonParser class) -

* all_function_names => get_all_function_names()

* all_function_docstrings => get_all_function_documentations()

* all_class_methods => get_all_class_method_names()

Roadmap

• Documentation: tutorial on queries writing

• Write *Parser class for other languages

If you are using tree-hugger in your project, please consider putting in your project :)