[chuck-users] Dealing with String objects?

Stefan Blixt stefan.blixt at gmail.com
Sat Dec 29 13:12:07 EST 2012 

Since a lot of stuff in ChucK owes to Java, and java.lang.String is a class
like any other, with the unique extra privilege of having its own kind of
constructor using double quotes, I had a hunch that something similar may
be the case here. Here's some experimental code:


-----------------------------------------

"oy" => string c;


<<< "tjo", c.length() >>>;

<<< "tjo", c.upper() >>>;

<<< "tjo", c.lower() >>>;


class Y extends string {

        fun string toString() {

                return "gabber";

        }

}


"jungle" => string o;


<<< "I like " + o.toString() >>>;


new Y => o;

Y y;


<<< "I also like " + o.toString() >>>;

<<< "But why not " + y.toString() >>>;

-----------------------------------------


At the top you can see the string type has at least three methods (length,
upper and lower). Below you can see that you can make a subclass of string
(trying the same thing with int causes an error).


Below that I tried to override toString() and use it, which doesn't quite
work (the second last line will not print the word "gabber", but the last
will. The compiler complains if I change the return type from string to
Object though, so it's clearly seeing it as an override of string's
toString().


It's also interesting that if I add this line:


<<< "Charred at ", o.charAt(0) >>>;


I get this message


[test.ck]:line(27): class 'string' has no member 'charAt'


(note the word 'class'). While this:


7 => int x;

<<< "Charred at ", x.charAt(0) >>>;


yields:


[test.ck]:line(27): type 'int' does not have members - invalid use in dot
expression



So while they may not have a whole lot of use as such, I'd say that strings
can be viewed as classes, and more crucially they are objects - something
complex that ChucK refers to rather than uses directly - a bit like arrays:



int a[1];

<<< "Charred at ", a.charAt(0) >>>;

----------v-------------

[test.ck]:line(31): class 'int[]' has no member 'charAt'



I found the reference to upper() and lower() here after googling around:

https://lists.cs.princeton.edu/pipermail/chuck-dev/2012-March/000435.html




On Tue, Dec 25, 2012 at 7:59 PM, Wolfgang Gil <wolfgang.gil at gmail.com>wrote:

> Hey,
>
> Mike, your suggestion sounds great. I look forward to hearing more about
> it.
>
> Kassen, thanks for the info. My german name was given to me in Venezuela,
> where I was born. I have not german family whatsoever. I am half
> venezuelan, half spanish, currently leaving in NY. Here I met my fiancée,
> a japanese lady I have been living with for the last four years. I use more
> chopsticks than fork and knife these days
> *
> *
> *C'est la vie ;)*
>
>
> On Mon, Dec 24, 2012 at 3:03 PM, mike clemow <michaelclemow at gmail.com>wrote:
>
>> Hey Wolfgang, Kas,
>>
>> So, a few years ago I wanted the same thing for intelligent casting
>> purposes.  Instances of Object type respond to the method toString()
>> as well as typeOf(), a stubbed out method in Object source code with
>> no implementation.
>>
>> My solution was modify the implementation of toString() to only return
>> the class name and inserted that into the stub for typeOf().
>>
>> After recompilation, I could call typeOf() on instances (or instances
>> of subclasses of) Object and get a string representation of that
>> object's type.
>>
>> I can be more specific about the change and the files involved when I
>> get back to my home after the holidays (Wednesday).
>>
>> Hope this helps!  It's an easy change.
>>
>> -mike
>>
>> //--
>> Sent from my Tracking Device.
>> --//
>>
>> On Dec 24, 2012, at 6:40 AM, Kassen <signal.automatique at gmail.com> wrote:
>>
>> > On Sun, Dec 23, 2012 at 03:45:45PM -0500, Wolfgang Gil wrote:
>> >> Hello chuckers
>> >>
>> >
>> > Hey Wolfgang!
>> >
>> >> I am looking for a reference to the 'string' object class in chuck. I
>> am
>> >> having a hard time trying to guess what methods are available for the
>> >> class.
>> >
>> > Sorry, but String is not a class, it is a primitive. Ok, it is a bit
>> > unusual primitive that sometimes acts a bit differently from int,
>> > float, dur, etc, but as far as I can remember those differences are
>> > bugs. String should be a primitive with all of the advantages
>> > (automatic instantiation) and all of the downsides (no member
>> > functions) of those.
>> >
>> > This is talking from the ChucK side, in the C++ source things might be
>> > different; I never looked at that part of the source.
>> >
>> >
>> >> I also recently came across with the StringTokenizer object but it
>> seems to
>> >> work only when the token is a white space. Is it possible to assign a
>> >> different token to the object?
>> >
>> > Sadly no, not that I know of. Do we need that?
>> >
>> >> What gets printed is the object's type plus what I believe is a
>> reference
>> >> to memory that I am currently not interested in, separated by a colon (
>> >> TriOsc:1001f36a0)
>> >>
>> >
>> > Way cool! I've long wanted this. Could I suggest a way to get a array
>> > of types in hierarchy? That way we could get something like;
>> >
>> > ["Object", "UGen", "StkInstrument", "Sitar"] //it's all of those
>> >
>> > or;
>> >
>> > ["float"] //floats are clearly not objects, even is strings are weird.
>> >
>> > That would be a great help when working with groups of objects that
>> > have some things in common and not others. If, for examplle, we'd just
>> > want a egg we could simply check whether the object is a "bird" and
>> > thus would support .getEgg(), we might not be interested in whether it
>> > has more detailed functions like .getBlueFeather() . In some cases
>> > that might save a lot of checks and clean stuff up a lot. I don't like
>> > big trees of IF's.
>> >
>> > Currently that is mostly relevant for the StkInstrument series and the
>> > Filter one, but I could see more sets like that and of course it would
>> > make sense for our own class hierarchies.
>> >
>> >>
>> >> Happy holidays!
>> >
>> > You too! Don't let my modest proposals keep you away from this choice
>> > reason to spend time with loved ones and food. There is probably some
>> > rule against suggesting more work on Dec.24th to people with European
>> > names. Sorry ;-)
>> >
>> > Yours,
>> > Kas.
>> > _______________________________________________
>> > chuck-users mailing list
>> > chuck-users at lists.cs.princeton.edu
>> > https://lists.cs.princeton.edu/mailman/listinfo/chuck-users
>> _______________________________________________
>> chuck-users mailing list
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>>
>
>
>
> --
>
> http://www.wolfganggil.com <http://www.wolfganggil.com/about>
>
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>


-- 
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