[Swift-devel] loops and strings

[Mihael Hategan]

I wish. I think we all need to think about it.

On Fri, 2007-07-27 at 18:32 +0000, Ian Foster wrote:
> Can you propose a general solution?
> 
> Sent via BlackBerry from T-Mobile
> 
> -----Original Message-----
> From: Mihael Hategan <hategan at mcs.anl.gov>
> 
> Date: Fri, 27 Jul 2007 13:24:34 
> To:Veronika Nefedova <nefedova at mcs.anl.gov>
> Cc:swift-devel at ci.uchicago.edu
> Subject: Re: [Swift-devel] loops and strings
> 
> 
> I see we're getting back to the same old story of the conflict between
> writing a mapper and hacking one directly in swift.
> 
> This is an issue we really need to deal with. It has produced more
> discussions and hacks than any other single Swift issue.
> 
> You could use an array, or we could provide a folding operator/function,
> or even a join function.
> We could also let fixed_array_mapper accept an array as a parameter, so
> you would build an array with the file names and then pass it to the
> mapper.
> 
> On Fri, 2007-07-27 at 11:09 -0500, Veronika Nefedova wrote:
> > I need to 'cat' together an unknown number of strings to form a  
> > string, thats why I was attempting to do it inside the loop. And even  
> > if I knew the number of loop cycles (say, its 68) -- are you  
> > suggesting  to do it 'by hand' ?
> > 
> > 
> > Anyway - my main goal is not to create this string, but to map an array:
> > file whamfiles_$s[] <fixed_array_mapper;files="$wham_string">;
> > 
> > Do you see a solution here?
> > 
> > Thanks,
> > 
> > Nika
> > 
> > 
> > On Jul 27, 2007, at 11:01 AM, Mihael Hategan wrote:
> > 
> > > wham_string2 = @strcat(wham_string, ", wham");
> > > print(wham_string2);
> > >
> > > Variables are not variables. They are labels that are used to  
> > > direct the
> > > data flow. Loops (in the sense of data looping around the same node -
> > > picture this as a data flow graph) make no sense.
> > >
> > > On Fri, 2007-07-27 at 10:50 -0500, Veronika Nefedova wrote:
> > >> So how else then I construct a string in swift ?
> > >>
> > >>
> > >> On Jul 27, 2007, at 10:46 AM, Mihael Hategan wrote:
> > >>
> > >>> Variables in swift are single assignment. You can't assign to a
> > >>> variable
> > >>> twice. What, in your opinion, should the error message be instead
> > >>> of the
> > >>> current one?
> > >>>
> > >>> On Fri, 2007-07-27 at 10:22 -0500, Veronika Nefedova wrote:
> > >>>> I am not sure if its possible to do string operations inside the  
> > >>>> loop
> > >>>> in swift?
> > >>>> I have a versy simple test code that doesn't work no matter what.
> > >>>> Obviously, I am missing something.
> > >>>> This is the code:
> > >>>>
> > >>>> file fls[]<filesys_mapper;pattern="*.prt",location=".">;
> > >>>> string wham_string = "#";
> > >>>> foreach prt_file in fls
> > >>>> {
> > >>>>        wham_string = @strcat (wham_string, ", wham");
> > >>>>        print (wham_string);
> > >>>> }
> > >>>> print (wham_string);
> > >>>>
> > >>>>
> > >>>> basically I expect to have this as an output:
> > >>>> #,wham,wham,wham,wham,... (its a test code (-;)
> > >>>>
> > >>>> instead I have these errors:
> > >>>>
> > >>>> wham_string is already assigned with a value of #
> > >>>> wham_string is already assigned with a value of #
> > >>>>          vdl:assign @ test.kml, line: 46
> > >>>>          vdl:mains @ test.kml, line: 39
> > >>>> Caused by: java.lang.IllegalArgumentException: wham_string is  
> > >>>> already
> > >>>> assigned with a value of #
> > >>>>          at org.griphyn.vdl.mapping.AbstractDataNode.setValue
> > >>>> (AbstractDataNode.java:255)
> > >>>>          at org.griphyn.vdl.karajan.lib.Assign.function
> > >>>> (Assign.java:70)
> > >>>> <snip>
> > >>>>
> > >>>>
> > >>>> In any case -- if I can't construct the string by using the loop -
> > >>>> how else could it be done?
> > >>>>
> > >>>> I use the constructed string then to map an array (I understand I
> > >>>> can't map individual array elements):
> > >>>>
> > >>>> file whamfiles_$s[] <fixed_array_mapper;files="$wham_string">; //it
> > >>>> was in the wrapper script before)
> > >>>>
> > >>>>
> > >>>> Nika
> > >>>>
> > >>>> _______________________________________________
> > >>>> Swift-devel mailing list
> > >>>> Swift-devel at ci.uchicago.edu
> > >>>> http://mail.ci.uchicago.edu/mailman/listinfo/swift-devel
> > >>>>
> > >>>
> > >>
> > >
> > 
> 
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