🚀 go-pugleaf

In <3171810F.2E2@funsys.se>, rrg@funsys.se (Robin Rosenberg) writes:
>Perhaps a side issue but my cents on the use and misuse of techical term.
>
[snips]
>
>We have been reading different books. My book (Eliis Horowitz: Fundamentals of 
>Programming Languages, Springer Verlag, 1984) says (quote, p.38.) 
>
>"A language is said to be *strongly  typed* if the type of all expressions 
> is known at compile-time". 
>
>Hence Smalltalk and LISP are *not* strongly typed.
>
>Perhaps you would like to refer to your source?
>
Well, we could all get into a battle of the books here. If we step back
and look at the language terms used, the word 'strong' is both vague
and perjorative - hey, who wants to use some wimpy 'weakly'-typed 
language? The fact is that the strong/weak distinction (originally introduced
to distinguish assembly languages from 'high-level' languages) was
useful (see the date of your book) but has been obsoleted by developments
in languages, concepts, operating systems and compiling techniques.

Instead of using the vague 'strong'/'weak' distinction, we should
use some more precise distinctions and then take the discussion up from 
there.

The pertinent distinctions would seem to be:

*How* typing takes place - the static/dynamic distinction.
*When* typing takes place - the early/late distinction.
*Breadth* of typing - how wide/narrow are the types handled
by the language? For example C and COBOL have only a handful
of types. Languages such as C++, ST, and Java, whose class
mechanism allows user-definition of types can permit finer
distinction of types. Eg in C a string can represent both an
address or a set of modem initialization instructions, and this
is the only way to implement them. In an OO language, different
classes can represent the two. I would judge the latter set of
languages to have a 'narrower' typing mechanism than the former.
>
>-- 
>Robin Rosenberg


Steve Parker

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