035 num powf

// std/num:powf — a^e for real e via exp(e*ln a). Integral non-negative
// exponents take the exact pow path. Negative base is |neg-base (complex is
// out of scope); a==0 with e<=0 is |non-pos; huge results |overflow.
import std/io
import std/num

std/num:lit(4)
| exact a |> std/num:lit(0.5)
    | exact b |> std/num:powf(a, e: b, prec: 30)
        | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
        | neg-base |> std/io:print.ln("nb")
        | non-pos |> std/io:print.ln("np")
        | overflow |> std/io:print.ln("of")
    | bad y |> std/io:print.ln("bad-b")
| bad x |> std/io:print.ln("bad-a")

std/num:lit(2)
| exact a |> std/num:lit(0.5)
    | exact b |> std/num:powf(a, e: b, prec: 30)
        | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
        | neg-base |> std/io:print.ln("nb")
        | non-pos |> std/io:print.ln("np")
        | overflow |> std/io:print.ln("of")
    | bad y |> std/io:print.ln("bad-b")
| bad x |> std/io:print.ln("bad-a")

std/num:lit(4)
| exact a |> std/num:lit(2)
    | exact b |> std/num:powf(a, e: b, prec: 30)
        | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
        | neg-base |> std/io:print.ln("nb")
        | non-pos |> std/io:print.ln("np")
        | overflow |> std/io:print.ln("of")
    | bad y |> std/io:print.ln("bad-b")
| bad x |> std/io:print.ln("bad-a")

std/num:lit(-4)
| exact a |> std/num:lit(0.5)
    | exact b |> std/num:powf(a, e: b, prec: 20)
        | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
        | neg-base |> std/io:print.ln("powf:neg-base")
        | non-pos |> std/io:print.ln("np")
        | overflow |> std/io:print.ln("of")
    | bad y |> std/io:print.ln("bad-b")
| bad x |> std/io:print.ln("bad-a")

std/num:lit(0)
| exact a |> std/num:lit(-1)
    | exact b |> std/num:powf(a, e: b, prec: 20)
        | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
        | neg-base |> std/io:print.ln("nb")
        | non-pos |> std/io:print.ln("powf:non-pos")
        | overflow |> std/io:print.ln("of")
    | bad y |> std/io:print.ln("bad-b")
| bad x |> std/io:print.ln("bad-a")