[Types-sig] Static typing considered HARD

[David Ascher]

On Sat, 4 Dec 1999, Uche Ogbuji wrote:

> > Even if we ignore static type checking Python 2 really has to do
> > something about the "misspelling problem." One extra character on a
> > method name can crash a server that has been running for weeks. Once
> > this problem is fixed, the term "static type checking" will become
> > meaningful. In the current environment, it is probably not and thus
> > should not be the first focus of a new types-sig.
> 
> I keep hearing this sort of thing, and I keep saying that it's a red
> herring.  Lack of static typing does _not_ prevent Python from being
> scalable to large-scale and production environments.  Our experience at
> FourThought, where many of our projects are small-enterprise systems
> built with Python and sometimes CORBA, will make it very hard for anyone
> to convince me so.  I think the experience of users such as eGroups
> supports my feeling.  

Actually, I think you've picked the wrong example here.  The engineering
manager at eGroups is frustrated at his inability to check their Python
code at compile-time, and it's not an accident that Scott Hassan (CTO of
egroups) coauthored with another eGrouper the pylint type-checking tool
they announced a few weeks ago.  Typechecking at compile time is a huge
issue for them.  (Interestingly, as of a few months ago, Python wasn't
their bottleneck -- their DB system was).

I see two very distinct problems, though -- one is the use of 'statically
typed variables', which requires fundamental changes to Python's
typesystem. The other is 'compile-time type/signature/interface checking',
which could probably be done coarsely with add-on tools without changing
the syntax or type system one iota (ok, maybe one or two iotas).

> see this "misspelling" problem.  Proper configuration-management
> procedures and testing, along with intelligent error-recovery, prevent
> such problems, which can also occur in the most strongly-typed systems.

Wouldn't you agree that enforcing these 'proper procedures' is much harder
in a language which doesn't do half the job for you?

--david 

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