On Wed, Nov 30, 2022, at 2:31 PM, Lele Gaifax wrote: > "Mike Bayer" <mike...@zzzcomputing.com> writes: > > > On Wed, Nov 30, 2022, at 10:30 AM, Lele Gaifax wrote: > >> On the former one, it would be nice if we could reduce the "distance" > >> between the new Range class and what popular drivers provide: > >> > >> - "empty" vs "isempty": both asyncpg and psycopg have a "isempty" > >> property, we could either rename the "empty" attribute or add an > >> property alias > >> > >> - bounds inclusiveness: both drivers expose that thru > >> "lower_inc"/"upper_inc" properties, while in SA we must say > >> `range.bounds[0] == '['` > >> > >> - infinite bounds: likewise, they both provide "lower_inf"/"upper_inf" > >> properties, whereas we must say `range.lower is None and not > >> range.empty` > >> > >> As you see, these are "syntactic sugar" differences, easily implemented > >> with some @properties. > > > > great, we can add those. > > Ok, I'll try to propose a issue/PR in the following days. > > >> > >> What is more substantial, that required slightly more impacting changes > >> in a few cases, is that the SA Range does not have an exact notion of > >> its "type", i.e. there is no way to determine the data type of an empty > >> or infinite range. > >> ... > >> So I wonder if it would be reasonable/doable/affordable if SA could grow > >> a "family" of classes, derived from current Range, one for each data > >> type, so that for example a DATARANGE column would be associated with a > >> DateRange instance. > > > how about we add a "type" field to Range itself? That would be an > > easier change and also remove the need for applications to deal with > > all kinds of different Range subclasses that mostly have identical > > behavior. > > Yes, it could be done that way too, but from the developer perspective, > how is he going to create Range instances? Changing the constructor to > require a "type" argument seems uglier than using a specific class.
well we could add functions to create Range objects with different types, or maybe class constructors like Range.new_daterange(x, y). We already have a class hierarchy with AbstractRange, I dont want to make *two* class hierarchies, that increases complexity and additionally none of the DBAPIs have type-specific range objects. > > > > > type-specific Range methods could be called off of each AbstractRange > > type subclass, such as how the AbstractRange._resolve_for_literal() > > method works. > > I will need to study that part. > > > > > The Range object itself should also become a typing.Generic so that we > > could pass around the type as Range[int] or Range[datetime], etc. > > Yes! > > bye, lele. > -- > nickname: Lele Gaifax | Quando vivrò di quello che ho pensato ieri > real: Emanuele Gaifas | comincerò ad aver paura di chi mi copia. > l...@metapensiero.it | -- Fortunato Depero, 1929. > > -- > SQLAlchemy - > The Python SQL Toolkit and Object Relational Mapper > > http://www.sqlalchemy.org/ > > To post example code, please provide an MCVE: Minimal, Complete, and > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > description. > --- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+unsubscr...@googlegroups.com > <mailto:sqlalchemy%2bunsubscr...@googlegroups.com>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/878rjsfddq.fsf%40metapensiero.it. > -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/4ad81dbc-8f84-4c87-a9c4-60986defdbfd%40app.fastmail.com.
