Dang it. :-) I just want to encourage you to continue pursuing this idea, one way or another.
On Thu, May 21, 2015 at 7:01 AM, Ben Hoyt <benh...@gmail.com> wrote: > Thanks. Good point about python-ideas -- I was thinking that after I sent > it too. I'll repost there soon. > > Out of interest, what specifically were you referring to as "definitely > cool" here: LINQ-style generator expressions that build SQL ala PonyORM, or > the more general feature of enabling AST access? > > -Ben > > On Wed, May 20, 2015 at 10:31 PM, Guido van Rossum <gu...@python.org> > wrote: > >> Hey Ben, this is probably a better topic for python-ideas. I'll warn you >> that a hurdle for ideas like this is that ideally you don't want to support >> this just for CPython. It's definitely cool though! (Using movie poster >> style quotes you can turn this into a ringing endorsement: "definitely >> cool" -- The BDFL. :-) >> >> On Wed, May 20, 2015 at 7:26 PM, Ben Hoyt <benh...@gmail.com> wrote: >> >>> Hi Python devs, >>> >>> Enabling access to the AST for compiled code would make some cool >>> things possible (C# LINQ-style ORMs, for example), and not knowing too >>> much about this part of Python internals, I'm wondering how possible >>> and practical this would be. >>> >>> Context: PonyORM (http://ponyorm.com/) allows you to write regular >>> Python generator expressions like this: >>> >>> select(c for c in Customer if sum(c.orders.price) > 1000) >>> >>> which compile into and run SQL like this: >>> >>> SELECT "c"."id" >>> FROM "Customer" "c" >>> LEFT JOIN "Order" "order-1" ON "c"."id" = "order-1"."customer" >>> GROUP BY "c"."id" >>> HAVING coalesce(SUM("order-1"."total_price"), 0) > 1000 >>> >>> I think the Pythonic syntax here is beautiful. But the tricks PonyORM >>> has to go to get it are ... not quite so beautiful. Because the AST is >>> not available, PonyORM decompiles Python bytecode into an AST first, >>> and then converts that to SQL. (More details on all that from author's >>> EuroPython talk at http://pyvideo.org/video/2968) >>> >>> I believe PonyORM needs the AST just for generator expressions and >>> lambda functions, but obviously if this kind of AST access feature >>> were in Python it'd probably be more general. >>> >>> I believe C#'s LINQ provides something similar, where if you're >>> developing a LINQ converter library (say LINQ to SQL), you essentially >>> get the AST of the code ("expression tree") and the library can do >>> what it wants with that. >>> >>> What would it take to enable this kind of AST access in Python? Is it >>> possible? Is it a good idea? >>> >>> -Ben >>> _______________________________________________ >>> Python-Dev mailing list >>> Python-Dev@python.org >>> https://mail.python.org/mailman/listinfo/python-dev >>> Unsubscribe: >>> https://mail.python.org/mailman/options/python-dev/guido%40python.org >>> >> >> >> >> -- >> --Guido van Rossum (python.org/~guido) >> > > -- --Guido van Rossum (python.org/~guido)
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