[chuck-users] object / class hacking

Andrew C. Smith acsmith at willamette.edu
Wed Sep 30 15:30:38 EDT 2009

> A check check in the source codes suggested chuck is using std::map for the
> associative array part. Then it is just to export to the chuck language
> iterator type and functions begin(), end().

Right, but as I understand it Robert wanted to use an array of
Objects. It seems that the associative array only works to associate
strings with values, so (for example) you couldn't do:

int foo[0];
1 => foo[Bar bar];

because the associations can't take an Object. You'd be left with
creating a symbolic string for every created Object, rather than
having an array of Objects that you could search through. Iterating
over the array seems so fast (especially if they're sortable) that
throwing a bunch of strings into the mix would be tough. Side thought:

class ObjectString {
 Object foo;
 string bar;
 ...(set, get, whatever)...

ObjectString hello;
Object @ null;
Object m[0];

SinOsc sine => hello.foo;

hello.foo @=> m[hello.bar];


null @=> m[hello.bar]; // removes object

So that then if you want to know if you have your object (hello), you
can just ask if m[hello.bar] != null. I'm not sure whether this code
will work or not, though, and all calls would have to be explicit (not
iterative--so you couldn't set all m[] Objects to a particular
parameter, I believe).

Also, the array doesn't seem to be a contiguous block of memory now
that we have operators << and popBack() and other dynamic array types.

I remembered, .size() is a get method pretty much like .cap(), but
.size(int) is a set method. Maybe .cap() is vestigial?

Andrew (thanks, Hans, for catching how I only sent this to you)

2009/9/30 Kassen <signal.automatique at gmail.com>:
> Hans;
>>> What is the difference exactly between .cap() and .size() ?
>> Don't know. I just needed array size, and started using size() :-).
> Working from memory;
> In previous versions of ChucK .cap() could be used to get the length of the
> array, it could also (undocumentedly) be used to (re)set the length though
> at the expense of re-initialising all elements.
> In .size() was added which can be used exactly like .cap() to get
> the size of the array. It is overloaded to set the size, which should not
> re-initialise the existing elements (this works as far as I'm aware) and
> which should initialise any new ones added (this does not always happen in
> practice). In the meantime .cap() is no longer overloaded to set array
> length.
> Why this is like it is I don't know, in theory it might have broken some
> code, like how we could set all array elements of a array of type int to 0
> while maintaining the same length using this;
> foo.cap( foo.cap() );
> more generally; using that we could re-initialise all elements without being
> aware of the type of the array. In practice I never heard about this
> resulting in any complaints.
> The current situation, however, *is* a bit unclear (if much preferable to
> the old one). I can see how potentially breaking code would be preferable to
> dramatically changing it's functionality without warning but I'm not sure
> that is the reasoning that led to the choices made.
> Personally I use .cap() to get lengths and .size( int) to set them, purely
> for readability reasons.
> Yours,
> Kas.
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