Fixnums

Currently, the full numeric tower is far from being implemented : only fixnums are available.

Technically, a fixnum is in range min_long/4 <= fixnum < max_long/4, where min_long and max_long are respectively the smallest and biggest long integer on a given architecture. Thus, on a machine where sizeof(long) == 8 (64 bits), -2^62^ <= fixnum < 2^62^.

Operations currently implemented on fixnums are : +, -, *, <, >, <=, >=, is, isnt, pr, prn.