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From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: Recursion or loop, design questions
Date: Sat, 18 Jul 2015 16:26:53 -0700
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Malcolm McLean <malcolm.mclean5@btinternet.com> writes:
> On Saturday, July 18, 2015 at 11:44:40 PM UTC+1, Keith Thompson wrote:
>> Malcolm McLean <malcolm.mclean5@btinternet.com> writes:
>> 
>> 
>> You're suggesting a language in which a function is called before its
>> arguments are evaluated?  I fail to see how that could make sense.
>> 
> There are two approaches.
>
> The C way is to say that the programmer has called foo with 2 =2
>
> foo(2+2);
>
> Ok, says the compiler. 2 +4 make 4. So what I'll do is generate a
> call to foo with 4.
>
> The other way is to say the programmer has called foo with 2+2.
>
> Ok, says the compiler. foo takes the parameter foo(x). So, anywhere
> I see x in foo, I'll replace it with 2+2.
>
> For simple functions, it makes no difference. But the second method
> is more powerful if you want to do fancy things. 

You're talking about call-by-name (which C doesn't support, though you
can emulate it with function pointers).

Still, in the case of a call like f(g(), h()), the calls to g() and h()
still must occur before f() returns (assuming f refers to its
arguments), so it still wouldn't make for a tail-recursive call.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"