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From: ok@goanna.cs.rmit.oz.au (Richard A. O'Keefe)
Newsgroups: comp.lang.misc
Subject: Re: Dynamic typing (part 3)
Message-ID: <5013@goanna.cs.rmit.oz.au>
Date: 20 Mar 91 07:11:35 GMT
References: <1991Mar15.153342.10670@rice.edu>
Organization: Comp Sci, RMIT, Melbourne, Australia
Lines: 31

In article <1991Mar15.153342.10670@rice.edu>, wright@datura.rice.edu (Andrew Wright) writes:
> I would like to see a concise summary of the claimed advantages of
> dynamic typing.  The claimed advantages of static typing are numerous
> and often argued (verification, efficiency, documentation, ...) but
> the advantages of dynamic typing are less often discussed.

Read "Object-Oriented Programming, an evolutionary approach"
by Brad J. Cox, Addison-Wesley, ISBN 0-201-10393-1.

If I can summarise his argument adequately in two sentences
(and I really don't think I can do justice to it):

	- The fewer irrelevant constraints a software component
	  includes in its interface, the easier it is to re-use
	  that component or to continue to use it in an evolving
	  application.

	- Latent typing is an effective way of removing some
	  irrelevant constraints from an interface.

This argument also supports Ada-style generics and ML-style
polymorpism.  Cox also discusses Ada generics.

The static/dynamic typing issue is just one instance of the
general early-binding/late-binding issue.

The argument for dynamic typing can be put in a nutshell:
    "don't put anything in writing if you're going to regret it later".

-- 
Seen from an MVS perspective, UNIX and MS-DOS are hard to tell apart.