esprima-python's Introduction

Esprima (esprima.org, BSD license) is a high performance, standard-compliant ECMAScript parser officially written in ECMAScript (also popularly known as JavaScript) and ported to Python. Esprima is created and maintained by Ariya Hidayat, with the help of many contributors.

Python port is a line-by-line manual translation and was created and is maintained by German Mendez Bravo (Kronuz).

Features

Full support for ECMAScript 2017 (ECMA-262 8th Edition)
Sensible syntax tree format as standardized by ESTree project
Experimental support for JSX, a syntax extension for React
Optional tracking of syntax node location (index-based and line-column)
Heavily tested (~1500 unit tests with full code coverage)

Installation

pip install esprima

API

Esprima can be used to perform lexical analysis (tokenization) or syntactic analysis (parsing) of a JavaScript program.

A simple example:

>>> import esprima
>>> program = 'const answer = 42'

>>> esprima.tokenize(program)
[{
    type: "Keyword",
    value: "const"
}, {
    type: "Identifier",
    value: "answer"
}, {
    type: "Punctuator",
    value: "="
}, {
    type: "Numeric",
    value: "42"
}]

>>> esprima.parseScript(program)
{
    body: [
        {
            kind: "const",
            declarations: [
                {
                    init: {
                        raw: "42",
                        type: "Literal",
                        value: 42
                    },
                    type: "VariableDeclarator",
                    id: {
                        type: "Identifier",
                        name: "answer"
                    }
                }
            ],
            type: "VariableDeclaration"
        }
    ],
    type: "Program",
    sourceType: "script"
}