[fpc-pascal] Syntax changes suggestions

[Martin]

On 17/07/2018 11:05, Henry Vermaak wrote:
> On Mon, Jul 16, 2018 at 03:02:42PM +0200, Sven Barth via fpc-pascal wrote:
>> Santiago A. <svaa at ciberpiula.net> schrieb am Mo., 16. Juli 2018, 13:41:
>>
>>> I have some suggestions of change to freepascal syntax, just to debate
>>>
>>> (All are backward compatible)
>>>
>>> - Declaring variables inside blocks, and loop variables
>>>
>> -> reduces readability -> no interest
> How can it reduce readability?  You move variables closer to where they
> are used, therefore reducing clutter in the main "var" section.
> Limiting variable scope is definitely a good thing, I sure hope you're
> not arguing against that.  That's why almost all languages encourage it.
>
On the contra side:

You could then have 2 or more differnt "i" variables in one procedure. 
That is hell to read.

Of course you could argue that you can only have a "nested" "i", if 
there is no local var "i" (current style local). And no other nesting.
Still 2 issues:
You could have 2 consecutive loops, with different typed "i". That can 
be confusing. (it may not be to you, but is still can be). Now you would 
need 2 different named loop counters (which to me is good).

But more troubling:
You do no longer have a complete list of all local vars. That means, if 
I want to add a (current style) local var "i", i may have to scan the 
entire procedure (maybe hundreds of lines) to find if there already is a 
nested "i" (or start the compiler to see if there is an error).
That would be a real burden added to pascal (and since I may have to 
work on other peoples code, it is no good to say that I could simply not 
use it....)

----------------------
Also lets make a distinction here:

What are we looking for:
A) Saving the (so called) work, of declaring the var on top? (Note: that 
the work is pressing ctrl-shift-c)?
B) Introducing vars with more fine grained scoping?

As for (A) I already expressed that I am against it. (there also is a 
recent thread on the forum where this was discussed, so look it up and 
read the arguments)

As for (B):
I don't know of any good proposal, but if there was it would have to be 
something like this: (I still dont like it, but if there was a good idea 
to bring it in shape...)

procedure Foo;
var
    a: Integer; // normal vor
scoped var
    b: integer;
begin
   //b can not be used here / it will be as if it does not exist
   a := bar();
   if a > 1 then begin
     scope b;  // must be first after begin
     b := 1;
   end;
   // b out of scope
   // scope for one statement (the entire for, including the begin end 
which as a compound statement is part of the for.
   with scope b do for b := 1 to 10 do ... ;
// alternatively
   using scope b do for b := 1 to 10 do ... ;
   scope b: for b := 1 to 10 do ... ;

So you still declare the var on top.

Again, this is to entertain an idea, which I personally do not like....

If you have a scoping problem in pascal, cut your code into smaller 
procedures.