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From: Bart <bc@freeuk.com>
Newsgroups: comp.lang.c
Subject: Re: else ladders practice
Date: Fri, 8 Nov 2024 18:03:54 +0000
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On 03/11/2024 17:00, David Brown wrote:
> On 02/11/2024 21:44, Bart wrote:

>> (Note that the '|' is my example is not 'or'; it means 'then':
>>
>>     (  c |    a )          # these are exactly equivalent
>>     if c then a fi
>>
>>     (  c |    a |    b )     # so are these [fixed]
>>     if c then a else b fi
>>
>> There is no restriction on what a and b are, statements or 
>> expressions, unless the whole returns some value.)
> 
> Ah, so your language has a disastrous choice of syntax here so that 
> sometimes "a | b" means "or", and sometimes it means "then" or 
> "implies", and sometimes it means "else". 

I missed this part of a very long post until JP commented on it.

As I mentioned above, "|" here doesn't mean 'or' at all. In "( ... | ... 
| ... )", the first means "then" and the second "else". (It also wasn't 
my idea, it was taken from Algol 68.)


> Why have a second syntax with 
> a confusing choice of operators when you have a perfectly good "if / 
> then / else" syntax?

if/then/else suits multi-line statements. (||) suits terms that are part 
of a larger one-line expression.

I might as well ask why C uses ?: when it has if-else, or why it needs 
P->m when it has (*P).m.




> Or if you feel an operator adds a lot to the 
> language here, why not choose one that would make sense to people, such 
> as "=>" - the common mathematical symbol for "implies".

It is not an operator, it is part of '(x | x,x,x | x)' syntax.