spec/math/random/source.bend source

spec/math/random/source.bend on the hub · documented module

import Baseimport ../../../src/math/u64.bend as W# What a source (the Source interface of src/math/random/rand.bend: a state# type S and a step ~next: S -> W.U64 & S) is observed to do: the sequence of# its outputs. Two sources with the same outputs are the same generator for# every function of rand.bend.def fst64(-S: Data, p: W.U64 & S) -> W.U64:  (x, s) = p  xdef snd64(-S: Data, p: W.U64 & S) -> S:  (x, s) = p  s# the first n outputs of the source from state sdef outputs(~S: Data, ~next: S -> W.U64 & S, n: Nat, +s: S) -> List<&2, W.U64>:  match n:    case 0n:      []    case 1n+p:      Con{fst64(S, next(s)), outputs(~S, ~next, p, snd64(S, next(s)))}