engine: pass tbl parameter explicitly instead of using default parame…

[mewmew]

…ter values

This helps make the header files in Source/*.h parsable from both
C and C++.

Any headers in SourceX can easily be C++ only, but keeping
the core Devilution code parsable as both C and C++ is
useful for integration into mods.

[glebm]

The original Diablo is compiled with a C++ compiler and there might be other C++ things in the Source headers. Is there a particular mod that you had issues compiling?

[mewmew]

The original Diablo is compiled with a C++ compiler and there might be other C++ things in the Source headers. Is there a particular mod that you had issues compiling?

Hi @glebm!

Thanks for the quick response :)

I know there are a few C++ things in the source files, but at least historically Devilution was compilable as C. We did this to try and get the Rich headers correct (diasurgical/devilution#111 (comment)).

It is true that Diablo also contained C++ code, but this was mostly due to linking against Storm. From the looks of it, most if not all Diablo code was written in C but used the .cpp extension. (We've hypothesized that the reason for this may be that Blizzard gave Condor the directive that Diablo had to be coded in C++, but Brevik and the others at Condor were more familiar with Assembly and C.)

Looking at the diablo.h header, there is a commented out section with extern "C" so every header has at one point in the past been compilable as C.

As for the mod I'm playing with, it's not much to look at yet, but it's located at https://github.com/sanctuary/djavul

Cheers,
Robin

[glebm]

Thanks Robin. Making headers C-compatible seems reasonable then, and can also open up writing mods in other languages (e.g. Rust).

[mewmew]

Thanks Robin. Making headers C-compatible seems reasonable then, and can also open up writing mods in other languages (e.g. Rust).

Indeed. That's the main idea. Djavul is written in Go, so at least we have a Proof of Concept mod in another language than C++.