[fpc-devel] "Blank slate" next version of FPC

Dimitrios Chr. Ioannidis d.ioannidis at nephelae.eu
Wed Feb 20 15:34:50 CET 2019


Στις 20/2/2019 3:36 μ.μ., ο Paul van Helden έγραψε:
>     > > 1. it makes it easier to see the whole picture just looking at
>     the loop
>     > > body, no need to scroll up; (The loop body might be just 10
>     lines of code,
>     > > whereas the whole containing function sometimes has 1000s)
>     > >
>     > > 2. it isoltates the scope of such variable(s), therefore
>     preventing some
>     > > sorts of accidental misuse outside of e.g. the containing loop
>     (which still
>     > > do happen to me ocasionally in Pascal).
>     >
>     > I've already tried to make these points, nobody seems to buy
>     it.  IIRC
>     > Michael (vC) said that functions shouldn't be that long, so then
>     it's
>     > not a problem (perhaps his world is perfect, but mine certainly
>     isn't).
>     Anyone can split a function in many others. It's not so difficult and,
>     actually, it should be done.
>     > I'm mostly more interested in limiting the scope to prevent
>     accidental
>     > use, like you.  It can also offer more fine grained control of where
>     > managed variables get freed.
>     Try to see restrictions as a good thing.
>     In this case, which Pascal doesn't allow to declare inline variables,
>     you must split big functions, which has many local variables, in
>     others to have a better understanding of the algorithm. At the end,
>     you might have a better design and reuse of the code. Everybody wins:
>     you, your code, Pascal team - as they don't need to change the
>     compiler - and Niklaus Wirth might not throw a curse in us.
> O dear, now I've dunnit...
> So the argument against is: (1) split your long functions, because you 
> should; and (2) Wirth didn't do it, so good it is not.

   Even if declaring variables as close as possible to where the 
variable will be used ( debugging wise not readability wise ) leads to 
more correct code, the problem is to avoid the temptation to use them in 
other places too.

   AFAIK, one of Pascal's primary design goals is to won't let you shoot 
yourself in the foot, and IMO that feature is not in that direction.


Dimitrios Chr. Ioannidis

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