[mercury-users] Proposed change to char literal syntax

[Julien Fischer]

On Thu, 5 Oct 2006, Michael Day wrote:

> Hi Ralph,
>
>> I agree.  In my experience, I usually start off thinking of using tricks
>> like this (although nothing as adventurous as this example), but
>> inevitably end up using longer, more meaningful names, such as
>> unicode_space.  It makes things much less confusing and error prone in
>> the long run; the extra typing is more than compensated for by the
>> reduced debugging effort.
>
> Well, I see it as similar to the way in which the standard library has a 
> bunch of different functions all called init: one returns a map, one returns 
> a bimap, one returns a bag... and yet if you use the wrong one, the compiler 
> will let you know.
>
> More specifically, I was trying to point out that if character literals were 
> actually just function calls, then there would not need to be any special new 
> syntax, as 'a' would still just be a quoted one letter symbol, that would 
> resolve to :- func char.a = char assuming that you had imported the char 
> module.

There's another issue here in that '' has a particular meaning in relation
to higher-order terms, see section 2.3 of the reference manual.
(Confusion between '' and functions like ' ' has resulted in broken code
in the past.)

Julien.
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