Re: Ada syntax questions

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 2020-12-17 23:39, DrPi wrote:

> Ada claims to have a better syntax than other languages.
> I'm fine with with, but...
> 
> 1) What about array indexing ?
> In some other languages, arrays are indexed using square brackets. In 
> Ada, parentheses are used for function calls and for array indexing.
> In the code "status := NewStatus(some_var);", you can't tell if 
> NewStatus is a function or an array.
> 
> 2) In Ada, a function without arguments is called without any parentheses.
> In the code "status := NewStatus;", you can't tell if NewStatus is a 
> function or a variable.
> 
> 
> For my knowledge, are there good reasons for these syntaxes ?

1. Separation of interface and implementation. Being array or function 
is an implementation detail of a map or a named entity.

Another example is pointer dereferencing. In Ada X.A is same as P.A. In 
C you have X.A vs P->A.

Yet another one. All instances of parametrisation in Ada deploy () 
parentheses. In C++ it would be <>, [], (), depending on semantically 
irrelevant context.

2. Languages that like C use bottom-up matching are forced to 
distinguish certain things prematurely on the syntax level. This is also 
the reason why you cannot use the result type to distinguish signatures 
in C++, but you can in Ada. Thus in C++ you would have something as 
disgusting as

    123ull

while in Ada it is just

    123

Long time ago anything but strictly bottom-up matching was considered 
too complicated or impossible. So artificial distinctions like () vs [] 
were invented and then promoted into orthodoxy.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de