036 num mod bases

// std/num rung 2 — exact mod (trunc-mod, sign follows the dividend),
// length/scale introspection, and integer base conversion. to-base refuses
// non-integers outright rather than emitting bc's digit-vector notation.
import std/io
import std/num

std/num:lit(17)
| exact a |> std/num:lit(5)
    | exact b |> std/num:mod(a, b)
        | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
        | div-zero |> std/io:print.ln("dz")
    | bad y |> std/io:print.ln("bad-b")
| bad x |> std/io:print.ln("bad-a")

std/num:lit(-17)
| exact a |> std/num:lit(5)
    | exact b |> std/num:mod(a, b)
        | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
        | div-zero |> std/io:print.ln("dz")
    | bad y |> std/io:print.ln("bad-b")
| bad x |> std/io:print.ln("bad-a")

std/num:lit(5.5)
| exact a |> std/num:lit(2)
    | exact b |> std/num:mod(a, b)
        | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
        | div-zero |> std/io:print.ln("dz")
    | bad y |> std/io:print.ln("bad-b")
| bad x |> std/io:print.ln("bad-a")

std/num:lit(7)
| exact a |> std/num:lit(0)
    | exact b |> std/num:mod(a, b)
        | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
        | div-zero |> std/io:print.ln("mod:div-zero")
    | bad y |> std/io:print.ln("bad-b")
| bad x |> std/io:print.ln("bad-a")

std/num:lit(1.234e5)
| exact a |> std/num:length(a): n |> std/io:print.ln("len={{ n:d }}") |> std/num:free(n: a)
| bad x |> std/io:print.ln("bad")

std/num:lit(1.234e-5)
| exact a |> std/num:scale(a): n |> std/io:print.ln("sc={{ n:d }}") |> std/num:free(n: a)
| bad x |> std/io:print.ln("bad")

std/num:lit(255)
| exact a |> std/num:to-base(a, base: 16)
    | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
    | non-int |> std/io:print.ln("ni")
    | bad-base |> std/io:print.ln("bb")
| bad x |> std/io:print.ln("bad")

std/num:lit(-255)
| exact a |> std/num:to-base(a, base: 2)
    | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
    | non-int |> std/io:print.ln("ni")
    | bad-base |> std/io:print.ln("bb")
| bad x |> std/io:print.ln("bad")

std/num:lit(1.5)
| exact a |> std/num:to-base(a, base: 16)
    | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
    | non-int |> std/io:print.ln("to-base:non-int")
    | bad-base |> std/io:print.ln("bb")
| bad x |> std/io:print.ln("bad")

std/num:from-base(s: "ff", base: 16)
    | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
    | bad-digit |> std/io:print.ln("bd")
    | bad-base |> std/io:print.ln("bb")

std/num:from-base(s: "1z", base: 10)
    | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
    | bad-digit |> std/io:print.ln("from-base:bad-digit")
    | bad-base |> std/io:print.ln("bb")

std/num:from-base(s: "-1010", base: 2)
    | exact r |> std/io:print.ln("{{ r:s }}") |> std/num:free(n: r)
    | bad-digit |> std/io:print.ln("bd")
    | bad-base |> std/io:print.ln("bb")