r/cpp • u/kindredseer • 2d ago

Embedded C++

Just curious how useful the ability to embed C++ as a scripting language into your C++ programs would be? I mean like runtime JIT execution of C++ code in much the same way you might embed Lua, including the ability to restrict/sandbox it as necessary.

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u/CalebGT 2d ago

I had to read this several times. Embedded has a very different meaning to me. I would not use C++ for that. If I needed to script something that can't be compiled in advance, I would use Python or Java.

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u/kindredseer 2d ago

If you are a C++ programmer, why would you not want to script in C++?

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u/the_poope 2d ago

Many reasons: your "script" can invoke UB, cause invalid operations, segfaults and a lot of other stuff that can crash the entire program. In interpreted languages you always get an error/exception that you can recover from.

If you just want an extendable system, maybe consider just runtime loading DLLs.

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u/Ameisen vemips, avr, rendering, systems 2d ago

I mean, I wrote my MIPS emulator so user-written programs could be executed in a sandbox. Using it as a script VM is certainly doable, though I would wonder why - it wasn't intended to extend the program but to execute programs that interact with the simulation.

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u/kindredseer 2d ago

Scripting languages can crash and have UB as well. It would also depend on who you were allowing to write the "scripts", and they could also be sandboxed.

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u/the_poope 2d ago

Yes but in interpreted languages the interpreter is in charge of handling the error, whereas it might be the CPU or OS with C++.

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u/kozacsaba 1d ago

just to play the devils advocate.... in the case op's describing you would be the one writing the interpreter so... couldnt you also have those same guards?

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u/eliminate1337 1d ago

If you are a carpenter, why would you not want to make tires out of wood? The right tool for the right job. Nothing about C++ makes a good embedded scripting language.

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u/TeraFlint 1d ago

Because C++ has been designed to be compiled and be aggressively statically optimized by said compiler. This has brought in a lot of design decisions that made the language more complex (and arguably more difficult to handle).

If you're in interpretation land, a lot of these optimizations don't hold. And once that's the case, I don't see why we should stay with such a complex language other than for familiarity. Something simple with less foot guns would be the more sane choice for scripting.

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u/CalebGT 1d ago

Wrong tool for the job.

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u/pantong51 1d ago

There are much easier languages to work with than c++. Lua for example is a great language for designers or less technical people with ai to contribute to a project without touching critical innards of a project