[Compiler-sig] Type checking

[Charles E Jenkins]

Hello to all. I hope this is the correct forum for asking about the whys and
wherefores of Python compilation.

I, too, am interested in seeing strong type-checking added to the language. I
wonder what technical reasons prevent strong runtime type-checking from being
added.

Here's how naive I am. I would think it would be as easy as

	def myFunc1( num is IntType )
	def myFunc2( any_list is ListType )
	def myFunc3( string_list is ListType of StringType )

To have superior type-checking, you'd need some way to define type-safe
constants:

	tconst AccessMode is IntType
		NONE = 0
		GUEST = 1
		USER = 2
		ADMIN = 3

	def setMode( mode is AccessMode ):
		if mode != AccessMode.NONE:
			blah blah blah

In the example above, calling setMode( 1 ) would result in an exception; you'd
be forced to use setMode( AccessMode.NONE )		

And, of course, functions can still accept an argument of any type if the 'is'
clause is omitted.

I call myself naive because this is so easy that there must be a very good
reason why Python doesn't have these facilities!

--  _________________
--  Charles E Jenkins -- MailTo:cjenkins@tec-usa.com