Re: Goo Nitpicks

[James Knight <jknight@xxxxxxxx>]

On Friday, August 2, 2002, at 12:41  PM, Jonathan Bachrach wrote:
> i would propose
>
>   (take x n) == (sub x 0 n) == x[0:n]
>
> and
>
>   (drop x n) == (sub x n (len x)) == x[n:]
>
> as is done in NESL (by guy e. blelloch).  what this doesn't cover are
> the cases where negative numbers are used as the second index.  i
> could have another sub, say sub* handles this case and keeps sub pure.

I'd have to say this is getting close to the point of overloading my 
brain's namespace. What python accomplishes with one simple 
easy-to-remember construct (x[a:b]), we are now proposing to use *four* 
names for? That seems rather overboard. 'take' and 'drop' really don't 
jump out at me as having the meaning you're trying to push them into 
either.

I'd have to say I see no reason for 'take' at all. It is not hard to 
type (sub x 0 n). The form which 'drop' replaces - (sub x n (len x)) - 
is somewhat cumbersome, but could perhaps be more easily accomplished by 
allowing (sub x n 'end).
"(dm sub (x|<seq> from|<int> below|(t= 'end)) (sub x from (len x)))".

James