Re: Answering an Ada/COBOL Question

[Brian Rogoff <bpr@shell5.ba.best.com>]

On Mon, 15 Nov 1999, Richard D Riehle wrote:
> In article <Pine.BSF.4.10.9911141057210.7241-100000@shell5.ba.best.com>,
> 	Brian Rogoff <bpr@shell5.ba.best.com> wrote:
> 
> >On Sun, 14 Nov 1999, Robert Dewar wrote:
> >> In article
> >> <Pine.BSF.4.10.9911132308290.27448-100000@shell5.ba.best.com>,
> >>   Brian Rogoff <bpr@shell5.ba.best.com> wrote:
> >> > I also found the ML version of the case syntactically much
> >> > nicer. Also, pattern matching works on more than just
> >> > sequences of booleans. Note that I am not commenting at all on
> >> > the suitableness of FPs for
> >> > fiscal programming, just on the claim of "most elegant case
> >> > design" for  COBOL.
> 
> Sorry, Brian.  I sometimes resort to hyperbole in my zeal to make
> a point.

No apologies necessary.

> >> These are not simply Booleans in COBOL, they are conditions,
> >> which are rather different in COBOL than other languages.
> 
> Yes. For those not accustomed to thinking in COBOL, this does not
> jump out at you.  Then again, COBOL programmers are typically not
> adept at thinking in terms of pattern matching. 

What is the difference?

> >> Make sure you really know the COBOL facility well (don't just
> >> rely on Richard's quick example) before deciding that the ML
> >> syntax is better for dealing with decision tables. Knowing and
> >> having used both languages, I definitely agree with Richard here
> >> and disagree with Brian. Yes the ML facility is general and
> >> powerful, No, it is not nearly as syntactically friendly and
> >> convenient as COBOL.
> 
> Thank you, Robert.  I realize my example was rather concise.  My
> original intent was to illustrate a point with regard to 
> _expressiveness_ versus _expressibility_ in response to some 
> comment made regarding Ada, et al.  
> 
> >That's fine, I respect your opinion, and readily acknowledge that I don't 
> >know COBOL, and hence, have no opinion on COBOL per se. A quick example or 
> >sequence of examples showing where COBOL is superior to ML or Haskell
> >would be appreciated. Since you know ML, you know that the pattern
> >matching facility does work over data types, and in the Caml dialects
> >there are niceties like pattern guards, range patterns, and stream
> >patterns.
> 
> "He convinced against his will, is of the same opinion still."  

That doesn't apply here. I'm easily convinced, if you're right. So far, 
I haven't seen a demonstration of the power of COBOLs case statement that 
makes me think it isn't a degenerate case of pattern matching on a boolean 
tuple. Robert asserted that it is better for programming decision tables,
but based on your short example, I think ML is superior. Does anyone who
knows both languages feel like posting some convincing code snippets?

> It is
> not my goal to persuade anyone that COBOL is superior to ML. 

The case I was thinking about ;-) was simply the COBOL conditional versus 
ML style pattern matching, not ML vs COBOL in general. 

> >It should be mentioned that there is a language used to program soft
> >real-time and distributed systems called Erlang. This language was
> >designed at Ericsson with a lot of "human engineering" effort, and one 
> >of the things its designers insist on as being responsible for its success
> >is its pattern matching syntax.
> 
> Erlang?   Clearly someone _expressiveness_ for ideas that could not
> be conveniently expressed in the languages they already knew.

See www.erlang.org. If you can find the paper on the development of the
language, it makes for interesting reading.

-- Brian