[Swift-devel] loops and strings

[Mihael Hategan]

On Fri, 2007-07-27 at 14:01 -0500, Veronika Nefedova wrote:
> will allowing multiple assignments to the same variable be a really  
> impossible thing to have in swift?

With what we currently have as "Swift", yes.

> 
> Nika
> 
> On Jul 27, 2007, at 1:24 PM, Mihael Hategan wrote:
> > 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
> >>>>>>
> >>>>>
> >>>>
> >>>
> >>
> >
>