[REBOL] Re: Problems with block of datatype!s
From: holger:rebol at: 12-Sep-2001 10:55
On Wed, Sep 12, 2001 at 09:40:34AM -0800, Tim Johnson wrote:
> I would like to be able to test a word for a
> match in a block whose members are datatypes.
>
> The example code doesn't do what I want it to do:
> >> types: [string! number!]
> == [string! number!]
> >> find types string!
> == none ; was hoping for [string! number!]
> >> types/1 = string!
> == false ; was hoping for 'true
> Just curious: what else do I need to do here?
Change
types: [string! number!]
to
types: reduce [string! number!]
The reason is: In your block, "string!" is an unevaluated
word (type word!), but in your call to 'find "string!"
gets evaluated and becomes the datatype! "string!". Words
are different from datatypes, so no match is found.
Reducing the block evaluates the words in it and converts
them to datatypes, allowing 'find to do what it should.
This is not a bug btw.
--
Holger Kruse
[holger--rebol--com]
