From: Jonathan Wallace <jonathan.wallace@...>
Date: 2006-10-17T09:35:11+09:00
Subject: Re: What is the reason for this syntax?

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On 10/16/06, Kevin Olemoh <darkintent@gmail.com> wrote:
>
> If you can't understand what someone was responding to who are you to
> talk about whether they understand compilers when you don't even
> understand the nature of the conversation to begin with? What I did


I apologize if I misunderstood your point.  As I mentioned before, I've
taken a compilers course and am moderately conversant in a concept called a
shift-reduce conflict during compiler/interpreter construction.  What you
are proposing would introduce a shift-reduce conflict into the language.  As
you may find if you research this topic, this isn't necessarily a problem as
it can be handled explicitly.  However, so far, you haven't made any
reference to a common experience in language construction.

It is interesting how often such conflicts occur in the novice's
creation/design of a language.  I myself fought many battles with them (and
often lost!)


> was reply to a comment from another person that started this line of
> conversation.  Then some one comes along and says that there is no
> issue and everyone who thinks there is are not knowledgeable enough
> about anything to even think about such a situation.  I disputed this,
> simply put this really had nothing to do with the technical aspects of
> any programming languages period, it was and is a very philosophical
> thing that was brought up by someone other than myself.


You've hit upon the crux of the issue.  Their point, which I echoed from an
admittedly more ignorant position than theirs, is that this is not a purely
philosophical position, but a design decision based on technical trade-offs
during the construction/evolution of ruby.  You may wish to argue semantics
here, but a semantic argument doesn't invalidate the fact this was a design
decision made by Matz (according to statements made by others in this
thread).

When I said that I felt that the else if keyword was unnessecary what
> I meant was that you should be able to do the following:
>
> if condition
> #stuff
> else
> if condition
> #stuff
> end
>
>
As opposed to:

if condition
#stuff
else
  if condition
  #stuff
  end
end?

Here's a great book on the subject of compiler theory:
http://www.amazon.com/Compilers-Principles-Techniques-Alfred-Aho/dp/0201100886

You should check it out.

My initial estimation of your education still stands as you have never
sought to address the shift-reduce conflict you wish to introduce into the
Ruby grammar.  However, in the case that you are cognizant of such theory
and just not versed in compiler vernacular, I apologize in advance and await
your instructive response that will elucidate my shortcomings and
ignorance.

Alternately, you could take this question to comp.compilers and watch both
of us get lost in theory.  In fact, I open my request to the list at large,
am I on the right track with attempting to understand the design decision
made in regards to this particular construct?

Rather than keep filling up the mailing list with off-topic posts, I'm happy
to continue the conversation off-list.

Sincerely,
 Jonathan

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