The third shaded paragraph tells how to do a while loop with ^:

--Kip Murray

Sent from my iPad

> On Nov 16, 2013, at 4:34 PM, Pascal Jasmin <[email protected]> wrote:
> 
> I do.
> 
> ^: either applies to y if v returns true, or returns y.
> 
> what I want is to stop application once v u y is true, and return the last u 
> y.
> 
> The application is searching for a unique (or non existing) value across 
> multiple locations, but once it is found, stop looking.
> 
> I tried something with {. to feed locations one at a time, and then $:@:}. as 
> the keep looking instruction, but I may not understand $: well enough.
> 
> 
> 
> 
> ----- Original Message -----
> From: R.E. Boss <[email protected]>
> To: [email protected]
> Cc: 
> Sent: Saturday, November 16, 2013 4:54:30 PM
> Subject: Re: [Jprogramming] repeatuntil and repeat while tacit    definitions 
>    possible?
> 
> Are you aware of http://www.jsoftware.com/help/dictionary/d202v.htm ?
> 
> 
> R.E. Boss
> 
> (Add your info to http://www.jsoftware.com/jwiki/Community/Demographics )
> 
> 
>> -----Original Message-----
>> From: [email protected] [mailto:programming-
>> [email protected]] On Behalf Of Pascal Jasmin
>> Sent: zaterdag 16 november 2013 21:32
>> To: [email protected]
>> Subject: [Jprogramming] repeatuntil and repeat while tacit definitions
>> possible?
>> 
>> 2 conjunctions with monad only versions shown for simplicity
>> 
>> repeatuntil =: 2 : 'for_i. y do. if. v"_ s =. u i do. s break. end. end.'
>> 
>> repeatwhile =: 2 : 0
>> out =. i.0
>> for_i. y do. if. v"_ s =. u i do. out break. else. out =. out , s  end.
> end.
>> )
>> 
>>    +:  repeatuntil (6 < ]) 2 1 3 2 4 5 2
>> 8
>>    +:  repeatwhile (6 < ]) 2 1 3 2 4 5 2
>> 4 2 6 4
>> 
>> both short circuit based on finding an exit condition.  I'd be surprised
> that a
>> tacit version is possible, but maybe through scan '/' and ^: ?
>> 
>> I understand that the example is silly overkill, but the main application
> is for
>> repeatuntil is searching in many locations sorted by the likelihood of
> finding it
>> in a location.
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