[fpc-pascal]Interface-only units (was: shared libraries interface)

Nikolai Zhubr s001 at hotbox.ru
Fri Aug 2 20:59:35 CEST 2002

Friday, 02 August, 2002, 19:39:57, Full_Name wrote:

> just 'papers over the cracks' imo. The concept of the compiled unit is at 
> fault. You're basically using a concept introduced to Turbo Pascal circa V2 
> (iirc) in the early part of the 1980's. Maybe Modula or some later language
Well, yes, nobody had to bother about .so's or .dlls in 1980's perhaps :)

> Unless there is some way of verifying that the interface in untampered with (a
> third file? a checksum?) and the compiler either will not compile the source or 
> at the very least issue a compiler warning, I'll not be using the feature 
> personally. There are some many better ways of doing this I think (another
Hmm. Are there any checksums currently used to ensure that some unit
needs to be recompiled? I guess no, just date/time. And, if definition
and implementation were kept in separate files, the same logic could be
applied: implementation should be recompiled along with other
dependants whenever definition has changed (has more recent date/time).
This won't help in distributing closed-source units though, but I
personally don't care about that.

> idea, ADA uses 'specification/header' and 'body' to split the code.) Moving
> away from the concept of a 'Unit' would make the usage clearer/cleaner and less 
> prone to problems with understanding.
I'm just looking into an ADA book - apparently yes, spec/body can be
separate there (No big surprise). IIRC modula-2 is even more clear in
this respect, and it is much closer to pascal :)) Perhaps it's worth
Best regards,
 Nikolai Zhubr
> Matt
> --

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> Nintendo, Inc, 1989

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