Re: [slang-users] Range array docs

[Manfred Hanke <Manfred.Hanke@xxxxxxxxxxxxxxxxxxxxxxxxxx>]

Hi Duke,

> I [...] couldn't find any mention of using the # prefix.

Two paragraphs above the example you're citing,
http://www.jedsoft.org/slang/doc/html/slang-11.html says: "a range-array
expressed in the form [a:b:#n] represents an array of exactly n elements
running from a to b inclusive. It is equivalent to a+[0:n-1]*(b-a)/(n-1)."

That is,
	[0 : 100 : 25]
is an array from exactly 0 to (in this case) 100, in steps of exactly 25
whereas
	[0 : 100 : #5]
is an array from exactly 0 to exactly 100, with exactly 5 elements.

Note that the array
>      [first-value : last-value : increment]
may or may not include `last-value'. (See the docs for the details.)
For example, [0 : 100 : 25] == [0 : 123 : 25], because 100 + 25 > 123.
Therefore, one has to be especially careful with non-integer valued
range arrays like [0 : 1 : .25] -- which is probably [0., .25, .5, .75].

Cheers,

Manfred


> The docs say:
> 
> --------------------------------8<--------------------------
> The syntax for the most general form of range array is given by
>       [first-value : last-value : increment]
> 
> --------------------------------8<--------------------------
> 
> The examples show e.g.:
> 
> [0:1:#5]        ==> [0.0, 0.25, 0.50, 0.75, 1.0]
> [0:-1:#3]       ==> [0.0, -0.5, -1.0]
> 
> The increment must be preceded by a # sign, I take it. I was looking
> for confirmation of this point, but couldn't find any mention of
> using the # prefix.
> 
> Perhaps the syntax explanation above, could be adjusted to reflect
> the need for the # prefix??  Just a suggestion ...
> 
> --
> Duke