Reduction of moose.lua sizing working now!

Utils/luarocks/share/lua/5.1/pl/permute.lua

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+--- Permutation operations.
+-- @class module
+-- @name pl.permute
+local tablex = require 'pl.tablex'
+local utils = require 'pl.utils'
+local copy = tablex.deepcopy
+local append = table.insert
+local coroutine = coroutine
+local resume = coroutine.resume
+local assert_arg = utils.assert_arg
+
+--[[
+module ('pl.permute',utils._module)
+]]
+
+local permute = {}
+
+-- PiL, 9.3
+
+local permgen
+permgen = function (a, n, fn)
+  if n == 0 then
+    fn(a)
+  else
+    for i=1,n do
+      -- put i-th element as the last one
+      a[n], a[i] = a[i], a[n]
+
+      -- generate all permutations of the other elements
+      permgen(a, n - 1, fn)
+
+      -- restore i-th element
+      a[n], a[i] = a[i], a[n]
+
+    end
+  end
+end
+
+--- an iterator over all permutations of the elements of a list.
+-- Please note that the same list is returned each time, so do not keep references!
+-- @param a list-like table
+-- @return an iterator which provides the next permutation as a list
+function permute.iter (a)
+    assert_arg(1,a,'table')
+    local n = #a
+    local co = coroutine.create(function () permgen(a, n, coroutine.yield) end)
+    return function ()   -- iterator
+        local code, res = resume(co)
+        return res
+    end
+end
+
+--- construct a table containing all the permutations of a list.
+-- @param a list-like table
+-- @return a table of tables
+-- @usage permute.table {1,2,3} --> {{2,3,1},{3,2,1},{3,1,2},{1,3,2},{2,1,3},{1,2,3}}
+function permute.table (a)
+    assert_arg(1,a,'table')
+    local res = {}
+    local n = #a
+    permgen(a,n,function(t) append(res,copy(t)) end)
+    return res
+end
+
+return permute