On 22.07.2015 20:20, Paul van Helden wrote:
On Wed, Jul 22, 2015 at 7:47 PM, Sven Barth <pascaldra...@googlemail.com
<mailto:pascaldra...@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..
Not without reworking quite some parts of the parser.
> 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.
Because with that you have specific locations where variables are
declared. You can see with one look (yes, I'm simplifying here) what
variables are used in the function even if you don't have a fancy IDE
that highlights it.
Regards,
Sven
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