Parrot allows you to push all of the string registers (pointers, actually) and integer registers onto their own private stack with pushs, pushi and restore them with pops and popi. (Numerics and PMC's with n/p respectively.) So you *can* write recursive subroutines after a fashion but effectively you make the entire register set local to each recursion:
set I0, 100
bsr FUNC
print I0 # Gives 100
end
FUNC: pushi
set I0, 56
popi
ret
local() for a particular registister can be emulated but it's a pain in the ass with something like:
set I0, 100
set I1, 200
set I6, 700
bsr FUNC
#
print I0 # 100, original value
print I1 # 0, new value
print I6 # 0, new value
end
# Local changes to I1 and I6 preserved
# think of this as unlocal() :)
FUNC: pushi # saves all integer registers
set I0, 0
set I1, 0
set I6, 0
save I1
save I6
popi
restore I6
restore I1
ret
The answer to your other question (asked in /msg) is that no, you can't peer down the stack or get the stack's depth at this time. However you can simulate peering into the stack just fine with the tools given. | 