That's a bit light on the details, and I can't make any sense of "To use stdio even you literally need kernel-level privileges on Console.", C's stdio doesn't require special privileges to use, nor does Crystal's, afaik.
More poignant examples would be `dirent.h` and `system`. Getting access to the file system on a console, or the ability to start up a process out of band is not allowed.
Which task? DragonRuby uses a custom mruby build to target cross platform game releases so their goal is to fit the Ruby lang spec, which Crystal does not adhere to.
I honestly thought that "ruby lang spec" was "whatever Matz ruby does." The ISO-IEC-30170 standard cited by mruby's readme seems to be laughably old but I can't obviously tell if mruby is a superset of the ISO or a subset. Their use of the phrase "part of the ISO standard" doesn't help
Matz is the creator and maintainer of Ruby, yes. mruby is a subset to my knowledge, and I don't think it's 100% parity with Ruby MRI (CRuby), which is basically what the lang spec is built around to my knowledge.
