rebol - How to compare to none -

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i have following block of data:

client: ["id" "1234" "name" "foobar" "custom_ip" none]

strangely, comparing "none" never seems work.

if none = (select client "custom_ip") [print "yay!"]

though when print select client "custom_ip" returns "none".

why this? can determine that value none?

there difference between literal value of type none! , word! spelling none.

one can (rightfully, imo) call bug console not differentiate these when giving output of expression:

>> none  ;-- word! looked value == none  ;-- value, , it's *not* word!

to less deceptive response console of value none word evaluated in case, can use mold/all

>> print mold/all none == #[none]

or can show type of result instead of result itself:

>> type? none == none!

although that's deceptive in sense similar reasons, looks word none! when it's datatype...

>> type? type? none == datatype!

anyway, got in example word none, hence:

>> if 'none = (select client "custom_ip") [print "oh..."] oh...

deceiving console output aside, it's doing predictable thing. there shorthand #[none] in rebol3 literal nones of #:

>> client: ["id" "1234" "name" "foobar" "custom_ip" #] >> if none = (select client "custom_ip") [print "hmm..."] hmm...

but construction syntax in flux in general; it's hard ultimate answer be.

mostly aware of distinction between word none , value of type none!, despite basic console's dodgy output. (i'll mention ren garden, instance, uses mold/all)


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