#53 Add a way to get the stack length

[Optimizer]

Currently, the shortest way to get the length of stack on the stack itself is:

]:B~B,

which is 6 bytes. It would be nice to have a way to put the length of stack on the stack in 2 bytes using some e? command

[Optimizer]

Not to mention that the above 6 byte code does not work if the stack contains just characters

For example,

': '. '- ]:B~B,

will try to evaluate the string ":.-" and fail.

[user23013]

5 bytes:

]_,+~

Works even if there are only characters.

[Optimizer]

Cool. Used this in my answer to save 1 byte! But it would still be nice to get a 2 byte operator for it :)