F# Floating point ranges are experimental and may be deprecated

Question

I\'m trying to make a little function to interpolate between two values with a given increment.

[ 1.0 .. 0.5 .. 20.0 ]

The compiler tells m

Answer 1

Updated version of Tomas Petricek's answer, which compiles, and works for decreasing ranges (and works with units of measure): (but it doesn't look as pretty)

let rec frange(from:float<'a>, by:float<'a>, tof:float<'a>) = 
   // (extra ' here for formatting)
   seq { 
        yield from
        if (float by > 0.) then
            if (from + by <= tof) then yield! frange(from + by, by, tof) 
        else   
            if (from + by >= tof) then yield! frange(from + by, by, tof) 
       }

#r "FSharp.Powerpack"
open Math.SI 
frange(1.0, -0.5, -2.1)

UPDATE I don't know if this is new, or if it was always possible, but I just discovered (here), that this - simpler - syntax is also possible:

let dl = 9.5 / 11.
let min = 21.5 + dl
let max = 40.5 - dl

let a = [ for z in min .. dl .. max -> z ]
let b = a.Length

(Watch out, there's a gotcha in this particular example :)