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From: Niklas Holsti <niklas.holsti@tidorum.invalid>
Newsgroups: comp.lang.ada
Subject: Re: why Ada type casting is different from other languages?
  newType(value)
   vs. (newType)value
Date: Sun, 13 Jul 2014 12:01:26 +0300
Organization: Tidorum Ltd
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Xref: news.eternal-september.org comp.lang.ada:20905
Date: 2014-07-13T12:01:26+03:00
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On 14-07-13 04:55 , Nasser M. Abbasi wrote:
> I am just wondering what is the rational of Ada choosing to use
>       type(value)
> 
> vs
>       (type)value
> 
> to do typecasting. does not type(value) appear as a function call?
> as in
> 
>      i := float(9);
> 
> vs.
> 
>      i := (float) 9;
> 
> Just wondering on this choice and its advantage over the more
> common syntax.

What do you mean, "common" :-) ? Most programming languages I have seen
have the Ada form, "type(value)", although the name of the conversion is
not always simply the type-name, but something more specific, at least
if the conversion loses information.

For example, Fortran 66:

- conversion from integer to float:  FLOAT(integer_expression)
- conversion from float to integer:  IFIX(float_expression)

Only C and its legitimate and illegitimate offspring and relatives use
the form "(type)value", as far as I know.

Ranting aside, the C form has the clear disadvantage that one must
remember precedence rules to understand what is being converted:

  is (float)i the same as (float)i + j,
  or is it the same as (float)(i + j) ?

In the Ada form, type(value), the parentheses nicely enclose the value
to be converted. Much better IMO.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
      .      @       .