Introduction

ParSitter.jl is a library for parsing and querying code. It supports parsing of code to abstract syntax trees (ASTs) and extracting information from the trees by executing code queries over the ASTs.

Querying code essentially consists in two operations: parsing the code and running a query over the code to verify that the query pattern is found in the code and optionally, to extract or capture specific parts of the code. Under the hood, the querying operation boils down to applying a tree pattern matching method with capturing of values. This paper provides a nice introduction into the main concepts behind the matching.

Features

• flexible tree matching for AbstractTrees.jl interface compatible trees
• low-level S-Expression-based code querying
• multiple structural tree matching methods
• pluggable language support through tree-sitter
• high-level domain-specific-language (DSL) -based code querying
• tested language support: Python, Julia, C, C# and R

Installation

ParSitter.jl is a registered package and can be easily installed with

using Pkg; Pkg.add("ParSitter")

or alternatively, using the pkg mode

] add ParSitter

Contents

• Usage
• • Intro
  • • Support functions for matching
  • Building trees
  • • Query trees
    • Code trees
  • Matching trees
  • • Basics
    • Querying trees
    • The :speculative match mode
    • Query DSL
    • Querying code
  • CLI-based parsing
  • • Installing tree-sitter languages
    • Running the CLI tool