MRI has more primitives of sort, but they're an implementation detail. Ruby itself conceptually only have objects.
MRI however implements some of them (integers, floats, symbols, true, false, nil, I might have forgotten one or two) using type tagged values instead of pointers to objects.
Type-tagging is easier to make fast for a highly gc'd dynamic language, as it reduces gc pressure substantially to not have to allocate lots of small objects without massive amounts of complex optimisations.
Comments
MRI has more primitives of sort, but they're an implementation detail. Ruby itself conceptually only have objects.
MRI however implements some of them (integers, floats, symbols, true, false, nil, I might have forgotten one or two) using type tagged values instead of pointers to objects.
Type-tagging is easier to make fast for a highly gc'd dynamic language, as it reduces gc pressure substantially to not have to allocate lots of small objects without massive amounts of complex optimisations.