## VARS

# sto (1)
1 'a' sto
-> stack size should be 0
'a' a
-> stack should be 'a', 1
erase

# sto (2)
2 'a' sto a
-> stack should be 2
erase

# rcl (1)
'a' rcl
-> stack should be 2
erase

# rcl (2)
'b' rcl
-> error should be 5
-> stack should be 'b'
erase

# sto in prog then rcl
3 << 'r' sto >> eval r 'r' rcl
-> stack should be 3, 3
erase

# purge (1)
a 'a' purge a
-> stack should be 2, 'a'
erase

# purge (2)
'a' purge
-> error should be 5
-> stack size should be 0