On Sun, Nov 24, 2013 at 5:46 AM, Martin Schreiber <mse00...@gmail.com> wrote:
> On Saturday 23 November 2013 18:55:00 Marcos Douglas wrote:
>> On Sat, Nov 23, 2013 at 8:20 AM, Martin Schreiber <mse00...@gmail.com>
> wrote:
>> > On Thursday 21 November 2013 08:32:57 Martin Schreiber wrote:
>> >> ...
>> >
>> > sub strfunc2(const avalue: msestring,para: boolean): msestring;
>> > begin
>> > if para then
>> > return 'The not string result';
>> > end;
>> >
>> > := 'The string result: '+avalue;
>> >
>> > end;
>> > "
>>
>> The 'return' returned? :)
>>
> Additional returns always were possible, the last mandatory 'return'
> before 'end' has been replaced by the assignment.
But if 'return' exists, why I will use ':= value'??? Two ways to do the same?
>> Why not this simple syntax?
>> "
>> sub strfunc2(const avalue: msestring,para: boolean): msestring;
>> begin
>> if para then
>> return 'The not string result';
>> end;
>> return 'The string result: '+avalue;
>> end;
>> "
>>
>> The 'return' keyword is simple, clean and readable... think about it,
>> please.
>>
> The last return is mandatatory and at fix position the others are not. I don't
> like that. It should be possible to program without 'return' completely
> because 'return' is dangerous if one overlooks it.
So, go back to 'RESULT' variable. ;-)
> "
> ...
> "
> After some time one needs to fix a bug:
> "
> begin
> result:= 0; //initilization
> if a then //long deeply nested processing
> result:= 123;
> else
> if b and c then
> result:= -100;
> else
> if not (a or b) then
> return 1000; //aua, the globflag will not be set!
> else
> result:= 88;
> end:
> end;
> end;
>
> globflag:= result > 0; //terminating statement, cleanup
>
> := result;
> end;
> "
>
> So it should be possible to completely work without 'return' statement
> (or 'exit' in Delphi). In order to cancel operation it is often better to use
> a goto.
You can not protect the programmers using this. Think. Even if you use
'return', 'result', whatever... if the programmer put a Exit on your
code the same error will happen! Bad programmers do it. They forget to
create some object, don't destroy them, etc. Who cares! No language
can protect all source.
> "
> var
> globflag: bool8;
>
> sub test(a: bool8, b: bool8, c: bool8): int32;
> var
> result: int32;
> label
> abort;
> begin
> result:= 0; //initilization
> if a then //long deeply nested processing
> result:= 123;
> else
> if c then
> goto abort; //abort processing
> end;
> if b and c then
> result:= -100;
> else
> result:= 88;
> end;
> end;
>
> abort:
> globflag:= result > 0; //terminating statement, cleanup
>
> := result;
> end;
> "
>
> Martin
Pardon me but your algorithm -- I know this is just an example -- is
wrong. You do not need to use GOTO.
Using the real Pascal:
"
begin
result:= 0; //initilization
if a then //long deeply nested processing
result:= 123
else
begin
if b and c then
result:= -100
else
begin
if not (a or b) then
begin
result := 1000;
globflag:= true;
exit;
end
else
result:= 88;
end;
end;
globflag:= result > 0;
end;
"
--
Marcos Douglas
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