Re: Command Languages Versus Programming Languages

On 10/10/2024 17:55, Rainer Weikusat wrote:

Muttley@DastartdlyHQ.org ignorantly rambled:

On Thu, 10 Oct 2024 16:09:49 +0100
Rainer Weikusat <rweikusat@talktalk.net> boring babbled:

Muttley@DastartdlyHQ.org writes:

Its syntax is also a horrific mess.

>
Which means precisely what?

>
Far too much pointless punctuation. An interpreter shouldn't need the vartype
signified by $ or @ once its defined, it should already know.

 For the purpose of variable declaration, how's the interpeter going to
know the type of a variable without being told about it? Obviously, not
at all.
 Perl has three builtin types, scalars, arrays and hashes and
each is denoted by a single-letter prefix which effectively creates
three different variable namespaces, one for each type. That's often
convenient, because the same name can be reused for a variable of a
different type, eg:
 my ($data, @data, %data);

Why would you want to do this?

$data = rand(128);
@data = ($data, $data + 1);
%data = map { $_, 15 } @data;
 it's also convenient to type and easy to read due to being concise.

Adding shifted punctuation at the start of every instance of a variable? I don't call that convenient!
So, $ is scalar, @ is an array, and % is a hash?

Outside of declarations, $ and @ really denote access modes/ contexts,
with $ standing for "a thing" and @ for "a number of things", eg
 $a[0]

is the first element of the array @a and

Now I'm already lost. 'a' is an array, but it's being used with $? What would just this:
  a[0]
mean by itself?

@a[-3 .. -1]
 is a list composed of the three last elements of @a.

Sorry, these prefixes look utterly pointless to me. This stuff works perfectly well in other languages without them.
I can write a[i..j] in mine and I know that it yields a slice.
What would a[-3 .. -1] give you in Perl without the @? What would $a[-3 .. -1] mean?
What happens if you have an array of mixed scalars, arrays and hashes; what prefix to use in front of a[i]?