!!!Stack-Operations

* [drop]
* [2drop|two-drop]
* [dup]
* [?dup|question-dup]
* [2dup|two-dup]
* [swap]
* [2swap|two-swap]
* [nip]
* [over]
* [2over|two-over]
* [under]
* [rot]
* [-rot|minus-rot]
* [roll]
* [-roll|minus-roll]
* [pick]
* [.s|dos-s]
* [clearstack]
* [depth]
* [s0|s-zero]
* [sp!|s-p-store]
* [sp@|s-p-fetch]