FYI, I've re-posted this on python-ideas now: https://mail.python.org/pipermail/python-ideas/2015-May/033621.html
-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) _______________________________________________ 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/archive%40mail-archive.com
