function</span> <span class="binding-type"><a href="https://github.com/janet-lang/spork/blob/7fd743ac09e857fe0ebd333bd7a56cd0df3876c3//spork/math.janet#L975">source</a></span> <pre class="binding-text">(permutations s &amp;opt k)

Returns permutations of length `k` from members of `s`</pre></div><hr><div class="binding"><span id="math/poisson-distribution" class="binding-sym">math/poisson-distribution</span> <span class="binding-type">function</span> <span class="binding-type"><a href="https://github.com/ja