Re: class wide iterable (and indexable)

["Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>]

On 1/22/19 11:02 PM, Randy Brukardt wrote:
> 
> They're not used more often because this fixes the length, and prevents
> operations on items with different lengths. Again, a string is not an
> array -- a Vector is a better model for a string.

I suspect we're talking about 2 different things.

The length is fixed just as it is for all array objects. I'm talking about a way 
to get arrays (current Ada meaning) with a fixed lower bound. Things with a 
variable length are something else altogether.

I used String simply because it was a convenient array type to use in the 
example. This made the example easier to understand because it didn't need an 
extra type definition that is irrelevant to explaining the concept.

I'm not discussing whether this is a useful implementation for strings. (A 
string is a sequence of characters, and one use of an array is sequences, so an 
array may be a suitable implementation for a string. I suspect many of your 
problems with strings are really problems with characters.)

With all that understood (I hope), I can restate my question as: Why do those 
who use arrays, and have difficulty with them having variable lower bounds, not 
use such constructs more often instead? Is it because the value of having 
constant indices across slices outweighs the negatives of variable lower bounds?

-- 
Jeff Carter
"This scene's supposed to be in a saloon, but
the censor cut it out. It'll play just as well
this way." [in a soda fountain]
Never Give a Sucker an Even Break
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