[Types-sig] New syntax?

Paul Prescod paul@prescod.net
Mon, 20 Dec 1999 07:55:42 -0600

Greg Stein wrote:
> ...
> Nah. No execution needs to take place. Just some data flow analysis. 

Let's be concrete:

if somefunction():
	class a:
		def b(self)->String: return "abc"
	class a:
		def b(self)->Int: return 5

How many type objects are created? What are there names? What is the
type of a? 


class a:
	def b(self)->String: return "abc"
for i in sys.argv:
	class a:
		def b(self)->Int: return 5


def makeClass():
	class a:
		def b( self ):
			return "abc"
	return a


This seems intractable to me. I got around this in my original proposal
by requiring all declaring classes to be *top-level*. In other words I
formally defined the subset of Python that does not require code
execution. If you can formally define the semantics of "data flow" then
I will be able to compare the proposals.

Note that I am half-way between you and Tim. I think that type objects
should be more like Python objects but I am willing to restrict where
they are created to make the problem tractable and the semantics

 Paul Prescod  - ISOGEN Consulting Engineer speaking for himself
The occasional act of disrespect for the American flag creates but a 
flickering insult to the values of democracy -- unless it provokes 
America into limiting the freedoms that are its hallmark.
           -- Paul Tash, executive editor of the St. Petersburg Times