opDollar()

[Dmitry Olshansky]

On 26.03.2011 11:03, Caligo wrote:
> "In the expression a[<expr 1>, ...,<expr k>], if $ occurs in<expr
> i>, it is rewritten as a.opDollar!(i)()."  -- TDPL, pg 380
>
> Is that correct? if so, could some one give an example code?  I don't
> understand the need for the parameter.
>
> Also, what is the signature for opDollar() in a struct.  I'm getting
> errors trying to implement this.
That parameter means number of dimension. When implementing some kind of 
multidimensional array (e.g. an 2D raster Image) you'd have:
img[$-1, $-1] = lastValue; // the first dollar should resolve to 
"width", the second to "height"

Now speaking of it's implementation - it's quite broken.
The relevant bug report is 
http://d.puremagic.com/issues/show_bug.cgi?id=3474 (vote up!)
Still it's not considered to be a critical one, since you can workaround 
it by:
img[img.width-1,img.height-1] = lastValue;

-- 
Dmitry Olshansky