Does Python use a special home-made parser, or does it use Yacc?

[Robert]

Or some other pre-packaged parser tool?

 

[Martin v. Löwis]

Or some other pre-packaged parser tool?

None of them: it's not YACC, not a pre-packaged parser tool, and not
a home-made parser. Instead, it uses pgen, a parser tool that is
included in the Python distribution (whether *that* was made at
home or at work, I don't know .

Regards,
Martin