John Snow <js...@redhat.com> writes: > TypeGuards wont exist in Python proper until 3.10. Ah well. We can hack > up our own by declaring this function to return the type we claim it > checks for and using this to safely downcast object -> List[str]. > > In so doing, I bring this function in-line under _pragma so it can use > the 'info' object in its closure. Having done this, _pragma also now > no longer needs to take a 'self' parameter, so drop it. > > Rename it to just _check(), to help us out with the line-length -- and > now that it's contained within _pragma, it is contextually easier to see > how it's used anyway -- especially with types. > > Signed-off-by: John Snow <js...@redhat.com> > > --- > > I left (name, value) as args to avoid creating a fully magic "macro", > though, I thought this was too weird: > > info.pragma.foobar = _check() > > and it looked more reasonable as: > > info.pragma.foobar = _check(name, value) > > Signed-off-by: John Snow <js...@redhat.com> > --- > scripts/qapi/parser.py | 26 +++++++++++++------------- > 1 file changed, 13 insertions(+), 13 deletions(-) > > diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py > index 16fd36f8391..d02a134aae9 100644 > --- a/scripts/qapi/parser.py > +++ b/scripts/qapi/parser.py > @@ -17,6 +17,7 @@ > from collections import OrderedDict > import os > import re > +from typing import List > > from .common import match_nofail > from .error import QAPISemError, QAPISourceError > @@ -151,28 +152,27 @@ def _include(include, info, incl_fname, > previously_included): > ) from err > > @staticmethod > - def _check_pragma_list_of_str(name, value, info): > - if (not isinstance(value, list) > - or any([not isinstance(elt, str) for elt in value])): > - raise QAPISemError( > - info, > - "pragma %s must be a list of strings" % name) > + def _pragma(name, value, info): > + > + def _check(name, value) -> List[str]: > + if (not isinstance(value, list) or > + any([not isinstance(elt, str) for elt in value])): > + raise QAPISemError( > + info, > + "pragma %s must be a list of strings" % name) > + return value > > - def _pragma(self, name, value, info): > if name == 'doc-required': > if not isinstance(value, bool): > raise QAPISemError(info, > "pragma 'doc-required' must be boolean") > info.pragma.doc_required = value > elif name == 'command-name-exceptions': > - self._check_pragma_list_of_str(name, value, info) > - info.pragma.command_name_exceptions = value > + info.pragma.command_name_exceptions = _check(name, value) > elif name == 'command-returns-exceptions': > - self._check_pragma_list_of_str(name, value, info) > - info.pragma.command_returns_exceptions = value > + info.pragma.command_returns_exceptions = _check(name, value) > elif name == 'member-name-exceptions': > - self._check_pragma_list_of_str(name, value, info) > - info.pragma.member_name_exceptions = value > + info.pragma.member_name_exceptions = _check(name, value) > else: > raise QAPISemError(info, "unknown pragma '%s'" % name)
While I appreciate the terseness, I'm not sure I like the generic name _check() for checking one of two special cases, namely "list of string". The other case being "boolean". We could acquire more cases later.
