any [
			set arg number! (append stack arg) |
			
			;****************************************
			; STACK COMMANDS
			;****************************************
			'CLEAR ( ; Clears the entire stack
				stack: head stack
				clear stack
			) |
			'DROP ( ; Deletes level one of the stack
				remove back tail stack
			) |
			'SWAP ( ; Swaps levels and 1 & 2
				stack: at tail stack -2
				reverse stack
			) |
			'OVER ( ; Copies level 2 into level 1, pushing old level 1 to 2
				; TO-DO: erreur si taille pile < 2
				append stack first at tail stack -2
			) |
			'ROT (  ; Moves level 3 to level 1, pushing up the stack. 
				; TO-DO: erreur si taille pile < 3
				append stack first at tail stack -3
				remove at tail stack -4 
			) |
			'ROLL ( ; Moves a specified level to level 1
				stack: head stack
				var: last stack
				; TO-DO: erreur si taille pile < dernier élément + 1
				; if lesser? length? stack add var 1 [error]
				remove back tail stack
				append stack first at tail stack negate var
				remove at tail stack negate add var 1 
			) |
			'ROLLD ( ; Moves level 1 to a specified level
				stack: head stack
				var: last stack
				; TO-DO: erreur si taille pile < var + 1
				; if lesser? length? stack add var 1 [error]
				remove back tail stack
				insert 	at tail stack negate var
						last stack
				remove back tail stack
			) |
			'PICK ( ; Copies a specified level to level 1
				stack: head stack
				var: last stack
				; TO-DO: erreur si taille pile < dernier élément + 1
				; if lesser? length? stack add var 1 [error]
				remove back tail stack
				append stack first at tail stack negate var
			) |
			'DEPTH ( ; Counts the number of active levels in the stack  placing the number on level 1
				append stack length? head stack
			) |
			'DUP (  ; Duplique le dernier élément au sommet de la pile
				stack: head stack
				append stack last stack
			) |
			'DUP2 ( ; Copies levels 1 & 2
				append stack copy at tail stack -2
			) |
			'DUPN ( ; Copies a specified number of levels again
				stack: tail stack
				var: first back stack
				remove back stack
				append stack copy at stack negate var
			) |
			'DROP2 ( ; deletes levels 1 & 2
				remove at tail stack -2
			) |
			'DRPN ( ; a specified number of levels are deleted
				stack: tail stack
				var: first back stack
				clear at stack negate add var 1
			) |
			
			;****************************************
			; OPERATORS
			;****************************************
			'+ (
				stack: at tail stack -2
				var: add second stack first stack 
				clear stack
				append stack var
			) |
			'- (
				stack: at tail stack -2
				var: subtract second stack first stack 
				clear stack
				append stack var
			) |
			'* (
				stack: at tail stack -2
				var: multiply second stack first stack 
				clear stack
				append stack var
			) |
			'/ (
				stack: at tail stack -2
				var: divide second stack first stack 
				clear stack
				append stack var
			) |
			;****************************************
			; TRIGONOMETRIC FUNCTIONS
			;****************************************
			'SIN (
				stack: head stack
				var: last stack
				remove back tail stack
				append stack sine var
			) |
			'COS (
				stack: head stack
				var: last stack
				remove back tail stack
				append stack cosine var
			)
		]

fwd-slash: to-lit-word

fwd-slash (
	stack: at tail stack -2
	arg: divide first stack second stack 
	clear stack
	append/only stack arg
)

fwd-slash: to-lit-word "/"