[REBOL] Re: [none idiom found?] The best shortcut word for "not none?"
From: lmecir:mbox:vol:cz at: 6-Sep-2006 13:38
Gabriele Santilli napsal(a):
> Hi Ladislav,
>
> On Tuesday, September 5, 2006, 1:41:57 PM, you wrote:
>
> LM> either value [do first value] [if default [do case]]
>
> I think you could write this as:
>
> do either value [first value] [case]
>
> with the assumption that case is none when the /default refinement
> has not been specified.
>
> Regards,
> Gabriele.
>
OK, here is the improved version, which I am proposing to Carl too:
REBOL [
Author: ["Ladislav Mecir" "Gabriele Santilli"]
Purpose: "A SWITCH alternative, see example"
]
switch1: func [
"Selects a choice and evaluates the first block that follows it."
[throw]
value "Value to search for."
cases [block!] "Block of cases to search."
/default case [block!] "Default case if no others are found."
][
if value: find cases value [value: find next value block!]
do either value [first value] [case]
]
example: [
switch1 1 [2 4 6 ['even] 1 3 5 ['odd]]
]
