Article View: comp.lang.misc
Article #6217Re: Turing programming language.
From: Mart van Stiphout
Date: Mon, 23 Jan 1989 22:22
Date: Mon, 23 Jan 1989 22:22
58 lines
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2712 bytes
> I think that loop statement in Turing is simple and easy to use. It is more
> powerful than the equivalent Pascal loops. For example:
Let me explain my objections to the Turing loop syntax.
My main objection is the location of the exit criterion. It is
inside the loop and generally will be surrounded by (lots ?) of
code. As we all know, the correctness of loops
can be shown by pre- and postconditions and the
invariant relation.
In my view, the stop criterion should not be located somewhere in the
middle of the loop. Furthermore, in my opinion your Pascal
examples of loops proof their superiority to the Turing loops:
the loop type is clear in a glance. I think it's ok to use different
notations for different loops
I'm not the greatest C fan, but I think C loops are just what
you need for correct loops. Let me compare the C and Turing loops:
C Turing
initialisation
for ( initialisation; condition; increment ) loop
{ exit when not condition
... code ... ... code ...
} end loop
initialisation initialisation
do { loop
... code ... ... code ...
while condition exit when condition
end loop
And what do you think of the following C version of your 1.5 loop?
while ( i = read() ) {
...code...
}
> You have a better point with collections. The Turing syntax:
I really like the idea of indexing linked list as if they were arrays.
At the moment I am really fed up with the minimal support of
languages like Pascal and C for linked lists. I always have
to create records (structs) and `next' pointers. Accessing or
adding list elements always requires extra source code for
rather trivial operations.
Why can't there be a programming language with type list that
automatically allocates memory if needed and allows treatment of
list in a similar way as arrays. Arrays are so much easier to
handle, give fewer errors and the code looks much better.
I'm really interested in other peoples opinions on these ideas.
---------------
Mart van Stiphout
Eindhoven University of Technology
email: mart@euteal.eutrc3.hp4nl.mcvac.uucp
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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!mcvax!hp4nl!eutrc3!euteal!mart From: mart@euteal.UUCP (Mart van Stiphout) Newsgroups: comp.lang.misc Subject: Re: Turing programming language. Summary: Reaction on Mark Mendells explanation of the Turing syntax. Keywords: programming language Message-ID: <12@euteal.UUCP> Date: 23 Jan 89 22:22:07 GMT References: <11@euteal.UUCP> <89Jan20.111000est.4328@turing.toronto.edu> Organization: Eindhoven University of Technology, The Netherlands Lines: 58