documentation/extensions/switcher/__init__.py

import os.path

from docutils import nodes
from docutils.parsers.rst import Directive

from pygments.lexers import get_lexer_by_name


def setup(app):
    app.add_directive('switcher', SwitcherDirective)
    app.add_directive('case', CaseDirective)

    app.connect('env-updated', add_statics)

    return {
        'parallel_read_safe': True,
        'parallel_write_safe': True
    }

def add_statics(app, env):
    app.add_js_file('js/switcher.js')
    env.config.html_static_path.append(statics())


statics = lambda *p: os.path.join(
    os.path.abspath(os.path.dirname(__file__)),
    'static', *p)


class SwitcherDirective(Directive):
    has_content = True

    def run(self):
        self.assert_has_content()

        body = nodes.compound('\n'.join(self.content), classes=['tab-content'])
        self.state.nested_parse(self.content, self.content_offset, body)

        titles = []
        for child in body.children:
            if isinstance(child, nodes.literal_block):
                titles.append(get_lexer_by_name(child['language']).name)
            else:
                assert child['names'], (
                    "A switcher case must be either a code block or a compound with a name"
                )
                titles.append(' '.join(child['names']))
        tabs = nodes.bullet_list('', *[
            nodes.list_item('', nodes.Text(title), classes=['nav-link'])
            for title in titles
        ], classes=['nav nav-tabs'] )
        node = nodes.compound('', tabs, body, classes=['content-switcher'])
        return [node]


class CaseDirective(Directive):
    required_arguments = 1
    final_argument_whitespace = True
    has_content = True

    def run(self):
        self.assert_has_content()
        node = nodes.compound('\n'.join(self.content), names=[self.arguments[0]])
        self.state.nested_parse(self.content, self.content_offset, node)
        return [node]