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Comment by skrebbel | Hacker News Reader

Could anyone explain to me what the difference with normal ruby is?

"Lightweight", does that mean:

    Small but slow?
    Big but fast?
    Quite small and quite fast, but with a half-assed library?
    Big, slow, but low RAM usage?

I understand from another comment that this is intended for embedded systems. Does that mean running it on a microcontroller without OS? Cause the moment you can flash Linux, you can use Ruby MRI, no?

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Yes, it would be nice to know what tradeoffs mruby makes and how they differ from the ones made by other ruby implementations

>I understand from another comment that this is intended for embedded systems.

Nope, he said embedding. He means things like Lua where you have a scripting language embedded in a program that is running on a faster lnaguage. Common in video game dev.

>Does that mean running it on a microcontroller without OS?

Nope, not necessarily. It being portable means it's plausible but it's an unlikely usage scenario. More likely, it means being able to use it across a variety of POSIX derivatives.

>Cause the moment you can flash Linux, you can use Ruby MRI, no?

Also not true. What a micro-distribution of Linux can run on is not necessarily something MRI Ruby can also run on.

Okok, I was wrong. Now, what's mruby for?

Think of it as a replacement for Lua. Something you will be able to include as a scripting subsytem in most other languages.

But LuaJIT 2 is insanely fast, even the Heavy / Fast Ruby isn't even anywhere near its speed. So why would one choose mRuby over Lua?

Heavy Ruby is not designed for speed, and much of its heaviness causes slowness. It's entirely possible/likely that mruby will be in the same ballpark as luajit2 soon after release.

LuaJIT 2 is fast because the Lua world has Mike, who is a genius.

That said, Lua is fucking weird.

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