[fpc-devel] Pascal Standard, and what we can do.

[Paul van Helden]

On Wed, Jul 22, 2015 at 7:47 PM, Sven Barth <pascaldragon at googlemail.com>
wrote:
>
> > I'm not a compiler programmer, but it almost seems like laziness that
> the second case is not possible already? Maybe something is really hard
> with multi-word operators?
>
> The compiler is geared towards single word operators (combined with their
> precedence).
>
Is it technically infeasible to expand this to two-word operators? SQL did
it..

> > Convenience should be added to this. Take for example type inference. If
> the compiler can easily figure out the type of a result, why should I have
> to declare a variable first with the appropriate type? Of course that means
> to allow var declarations inside the code block. Something I've always
> wanted to see in Pascal since my brief stint with C++ in the early 90s. The
> standard argument against is probably "that is unPascallish" or that it is
> moving away from strong typing. I disagree: if the compiler can figure
> things out before runtime you still have strong typing. So, for example, I
> would like to declare something like this anywhere inside a begin..end
> block:
> >
> > var A := SomeClassInstance.SomeFunction;
>
> While I agree that type inference /might/ be useful I don't agree with
> inline variable declarations. One of the main points of Pascal is declare
> before use. While this is somewhat violated with Delphi compatible generics
> there one could at least argue that the specialized type is implicitly
> declared by the generic declaration...
>
I have never managed to understand why "declare before use" is so important
to Pascal. I get the bit about strong typing and doing everything possible
to eliminate errors at compile time, but I still don't get why. If this is
central to what makes something "Pascal", I would love to be pointed to a
good explanation. I'm not trying to be a pain here. I've been programming
in Pascal, full time, for most of my life. It has always puzzled me why
everything has to be declared first.
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