[REBOL] Useful Missing Series! Functions
From: robbo1mark:aol at: 4-Jul-2001 6:56
Everybody,
Here's a few simple, useful series! functions which are
currently missing from REBOL.
These are SWAP, SLICE & POP.
SWAP unsurprisingly swaps the positions of two values in
a series!.
SLICE return a copy of a series between two inclusive index
positions.
POP returns the first value of a series and removes it from
the series.
Here's the FUNC's below.
Feel free to post re-factored optimised versions, I welcome this.
cheers,
Mark Dickson
-----------------------------------------------------------------
SWAP FUNCTION
swap: func [
series [series!] /local x y
] [
x: first series y: second series
remove/part series 2
return back back insert series reduce [y x]
]
; examples
>> swap "ehllo"
== "hello"
>> swap [b a c]
== [a b c]
>> swap at [a c b] 2
== [b c]
>> head swap at [a c b] 2
== [a b c]
SLICE FUNCTION
slice: func [
series [series!] start [integer!] end [integer!]
] [
return copy/part at series start (end - start) + 1
]
; examples
>> slice [ a b c d e f g] 2 4
== [b c d]
>> slice "alphabet soup" 1 5
== "alpha"
>> slice at "alphabet soup" 9 1 5
== " soup"
>>
POP FUNCTION
pop: func [
series [series!] /local x
][
x: first series
series: remove series
return x
]
; examples
>> pop a: [1 2 3]
== 1
>> a
== [2 3]
>> pop a: "Hello"
== #"H"
>> a
== "ello"
