Hi,
20.02.2019 21:28, Giuliano Colla:
[...]
I have just met such a situation: I ported from C++ to Pascal an
algorithm for the computation of the kinematics of a Delta Robot, and I
was badly bitten.
In that case you are just dealing with X,Y,Z coordinates, and
Theta0,Theta1,and Theta2 angles, and you find, in the body of a
procedure, some X,Y,Z or Theta which have global scope, and some which
are just local to some smaller (but not too small) block and which are
redeclared inline. Rather hard to tell them apart.
Excellent! Such redeclarations should obviously be borbidden. Otherwise
it would loose almost the whole point. Java certainly rejects them.
And, it is easy to identify and reject such name clashes in this case,
because the offending statement (declaration) can clearly be located.
On the other hand, I've been biten plenty by the already existing name
clashes like:
with Button1 do
begin
Left := ClientWidth div 2;
.....
and here nothing can probably be done to help at compiler part, because
the statement is perfectly valid despite so obviously erroneous. I've
seen some people even prepending "self." to almost any identifier in a
desperate attempt to eliminate ambiguities. (And yes, it looked
disgusting enough)
Thank you,
Regards,
Nikolai
Redeclaring inline an index I, which you'll be then using a lot of
times, is the best way to shoot you in the feet. Pascal encourages you
to use I,J,K at first, then ii,jj,kk etc.
Moreover, using a modern tool such as Lazarus, you never need to scroll
1000 lines to find a declaration: you just press alt+Up to go to the
declaration of the symbol over the cursor, and Ctrl+H to go back to the
line of code.
Keeping all declarations separated from code is just good programming
practice. Mixing declaration and code is bad programming practice, IMO,
and I appreciate Pascal for not supporting it.
Giuliano
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