repeat . . . delimit by

Richard Gaskin ambassador at fourthworld.com
Mon Sep 16 01:44:53 CEST 2013


It may also be helpful to remember that lineDel and itemDel are purely 
arbitrary; that is, they needn't be limited to use only on what we might 
think of as lines and items.

The only general rule governing them is that the engine will insist that 
"lines" be a larger chunk type than "items" (you can get item 2 of line 
1, but you can't get line 2 of item 1) - but beyond that you're free to 
use whatever delimiters you like.

For example, the original handler was:

set the itemDel to vtab
repeat for each item theDat in theData
    set the itemDel to tab
    do something
    set the itemDel to vtab
end repeat

Here rewritten to use both delimiters:

set the lineDel to vtab
set the itemDel to tab
repeat for each line theDat in theData
    do something
end repeat

--
  Richard Gaskin
  Fourth World
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  > repeat . . . delimit by
> Alex Tweedly alex at tweedly.net
> Mon Sep 16 01:32:46 CEST 2013
>
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>
> I do like the idea of  " repeat for each ... DELIMITED BY ..."
>
> But, in the meantime there might be some alternatives to help your code
> be nicer.
>
> Do you use lines (i.e. process based on CRs) in these loops ?
>    If not, would it help your current code to use the fact that you can
> change the linedelimiter ?
>
> set the lineDel to vTab
> repeat for each line tDat in theData
>     do something to tDat (i.e. using tab as item delimiter)
> end repeat
> set the lineDel to CR
>
> Note it's OK to *have* Crs in the data, so long as you aren't processing
> based on them.
>
>
> If that's not an option, then (less efficiently) you could do
>
> split theData by vtabs   -- gives a numerically indexed array
> repeat with I = 1 to the number of lines in the keys theData
>     put theData[I] into tData
>     do something with tData
> end repeat
>
> If you need the data back as a string, rather than simply  combine it -
> take a copy initially and split the copy.
>
> -- Alex.
>
>
>
> On 15/09/2013 00:10, Dr. Hawkins wrote:
>> While we're asking for modest syntax changes . . .
>>
>> Being able to state DELIMIT BY in a REPEAT, and having it stick (as opposed
>> to using the current value of the itemdelimiter) would be a huge help.
>>
>> It would avoid ugliness like
>>
>> set the itemDel to vtab
>> repeat for each item theDat in theData
>> set the itemDel to tab
>> do something
>> set the itemDel to vtab
>> end repeat
>>
>> While missing the last reset to vtab is a programming error, mu code is
>> kind of
>> littered with these (constant db accesses)
>>
>> code would be much easier to follow (and maintain) with
>>
>> repeat for each item theDat in theData DELIMTED BY vtab
>> do something
>> end repeat
>>
>> And while I'm at it, it's been mentioned before, but a Fortran-style
>> optional tying of the end repeat to the repeat with a constant would be
>> really helpful (same for switch, and so forth)
>>
>> [Fortran 90+, not FORTRAN IV!!!!]
>
>




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