John Snow <js...@redhat.com> writes:
> On 9/22/20 6:22 PM, Eduardo Habkost wrote:
>> On Tue, Sep 22, 2020 at 05:00:32PM -0400, John Snow wrote:
>>> Code style tools really dislike the use of global keywords, because it
>>> generally involves re-binding the name at runtime which can have strange
>>> effects depending on when and how that global name is referenced in
>>> other modules.
>>>
>>> Make a little indent level manager instead.
>>>
>>> Signed-off-by: John Snow <js...@redhat.com>
>>> ---
>>> scripts/qapi/common.py | 51 +++++++++++++++++++++++++++++-------------
>>> scripts/qapi/visit.py | 7 +++---
>>> 2 files changed, 38 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
>>> index cee63eb95c..e0c5871b10 100644
>>> --- a/scripts/qapi/common.py
>>> +++ b/scripts/qapi/common.py
>>> @@ -93,33 +93,52 @@ def c_name(name, protect=True):
>>> pointer_suffix = ' *' + eatspace
>>>
>>> -def genindent(count):
>>> - ret = ''
>>> - for _ in range(count):
>>> - ret += ' '
>>> - return ret
>>> +class Indentation:
>>> + """
>>> + Indentation level management.
>>> + :param initial: Initial number of spaces, default 0.
>>> + """
>>> + def __init__(self, initial: int = 0) -> None:
>>> + self._level = initial
>>> -indent_level = 0
>>> + def __int__(self) -> int:
>>> + return self._level
>>> + def __repr__(self) -> str:
>>> + return "{}({:d})".format(type(self).__name__, self._level)
>>> -def push_indent(indent_amount=4):
>>> - global indent_level
>>> - indent_level += indent_amount
>>> + def __str__(self) -> str:
>>> + """Return the current indentation as a string of spaces."""
>>> + return ' ' * self._level
>>> + def __bool__(self) -> bool:
>>> + """True when there is a non-zero indentation."""
>>> + return bool(self._level)
>>> -def pop_indent(indent_amount=4):
>>> - global indent_level
>>> - indent_level -= indent_amount
>>> + def increase(self, amount: int = 4) -> int:
>>> + """Increase the indentation level by `amount`, default 4."""
>>> + self._level += amount
>>> + return self._level
>>> +
>>> + def decrease(self, amount: int = 4) -> int:
>>> + """Decrease the indentation level by `amount`, default 4."""
>>> + if self._level < amount:
>>> + raise ArithmeticError(
>>> + f"Can't remove {amount:d} spaces from {self!r}")
>>> + self._level -= amount
>>> + return self._level
>>> +
>>> +
>>> +indent = Indentation()
>> Personally, I would keep the push_indent(), pop_indent() API, and
>> introduce an indent() function, to follow the existing API style
>> of plain functions.
>> Something like:
>> indent_prefixes = []
>> def push_indent(amount=4):
>> """Add `amount` spaces to indentation prefix"""
>> indent_prefixes.push(' '*amount)
>> def pop_indent():
>> """Revert the most recent push_indent() call"""
>> indent_prefixes.pop()
>> def indent():
>> """Return the current indentation prefix"""
>> return ''.join(indent_prefixes)
>> What you did is still an improvement, though, so:
>> Reviewed-by: Eduardo Habkost <ehabk...@redhat.com>
>>
>
> Yeah, there's only one user right now, so ... I just kinda wanted to
> get rid of the global usage. Maybe if we make the code generator
> fancier we'll find out what form is best.
You don't get rid of the global variable, you just change it from
integer to a class. A class can be handier when generating multiple
things interleaved, because you can have one class instance per thing.
Note that we already have a class instance per thing we generate:
instances of subtypes of QAPIGen. The thought of moving the indentation
machinery into QAPIGen or or maybe QAPIGenCCode crossed my mind many
moons ago, but I had bigger fish to fry, and then I forgot :)
John, I suggest you don't try to make this pretty just yet. Do what
needs to be done for the type hint job. We can make it pretty later.
