I want to wake this thread up again. can we get some arguments pro/
con to converting select() to work in a "generative" style ?
"generative" means either just the first, or both of these two things:
- methods like "append_whereclause()" return a select object with
which to call further genreative methods. this is a good thing
because you can say select.append_whereclause().order_by().group_by()
etc.
- the select object you get back is a *copy* of the object which you
called.
advantages include:
* is more "Pythonic" (not sure why this is, Mike Orr said so,
would like more exposition)
* you might want to reuse the original object differently (is that
such a common pattern ? seems weird to me..more exposition here too)
* would be consistent with orm's Query() object which has made its
choice on the "copy" side of things
disadvantages:
* inconsistent ? the select() function also takes a whole
assortment of arguments which can construct the entire instance at
once. the generative API already adds more than one way to do it.
* performance. an application that builds queries on the fly and
executes them will be generating many copies of a select(), most of
which are thrown away. if the ORM uses these approaches as well,
latency is added throughout.
for performance considerations, select() can implement both a
generative and a non-generative API (in fact it will always have a non-
generative API for adding modifiers anyway, just that its marked with
underscores as semi-private). this can be specified either via
constructor argument or by a different set of methods that are "non-
generative". however, either of these ideas complicate the select()
object. we might want to go with just a flag "generative=False" that
quietly allows an application to optimize itself. or we might want to
say, "build the select object all at once" if the overhead of
generativeness is to be avoided.
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