def as_ratio

bend-collections-laws-math@1.0.0.0 · spec/math/f64.bend:584

import Base
import bend-collections-laws-math@1.0.0.0/spec/lib/common.bend as C
import bend-collections-laws-math@1.0.0.0/src/math/f64.bend as F
import bend-collections-laws-math@1.0.0.0/src/math/num.bend as N

584# x = +-num / 2^den in lowest terms: the significand with as many of its
585# trailing zeros moved into the denominator as the scale allows; a zero is
586# 0/1 (Python's ints have no -0); NaN is a domain error, an infinity or an
587# integer of 2^64 or more an overflow (3.3)
588def as_ratio(+x: F.F64) -> Result<&2, &2, N.NumError, Rat>:
589  pick(Result<&2, &2, N.NumError, Rat>, is_nan(x), Fail{N.BadDomain{}}, pick(Result<&2, &2, N.NumError, Rat>, is_inf(x), Fail{N.Overflow{}}, pick(Result<&2, &2, N.NumError, Rat>, is_zero(x), Done{Rat{False{}, 0n, 0n}}, pick(Result<&2, &2, N.NumError, Rat>, Nat.is_le(zb(), xexp(x)), pick(Result<&2, &2, N.NumError, Rat>, C.fits(64n, int_part(x)), Done{Rat{sign(x), int_part(x), 0n}}, Fail{N.Overflow{}}), Done{Rat{sign(x), C.high(Nat.min(tz(64n, mant(x)), Nat.sub(zb(), xexp(x))), mant(x)), Nat.sub(Nat.sub(zb(), xexp(x)), Nat.min(tz(64n, mant(x)), Nat.sub(zb(), xexp(x))))}}))))