-- diagstacks.lua: the stack, the metastack, and the arrays "nodes" and "arrows". -- This file: -- http://angg.twu.net/dednat6/dednat6/diagstacks.lua.html -- http://angg.twu.net/dednat6/dednat6/diagstacks.lua -- (find-angg "dednat6/dednat6/diagstacks.lua") -- Author: Eduardo Ochs -- Version: 2015aug16 -- License: GPL3 -- -- «.Stack» (to "Stack") -- «.MetaStack» (to "MetaStack") -- «.nodes» (to "nodes") -- «.arrows» (to "arrows") require "stacks" -- (find-dn6 "stacks.lua") -- «Stack» (to ".Stack") -- TODO: unify with: (find-dn6 "stacks.lua" "Stack") --[==[ push = function (stack, o) table.insert(stack, o) end pop = function (stack, msg) assert(#stack > 0, msg or "Empty stack") return table.remove(stack) end popuntil = function (stack, depth) while #stack > depth do pop(stack) end end pick = function (stack, offset) return stack[#stack - offset] end pock = function (stack, offset, o) stack[#stack - offset] = o end Stack = Class { type = "Stack", __tostring = function (s) return mytabletostring(s) end, __index = { push = push, pop = pop, popuntil = popuntil, clear = function (s) s:popuntil(0) end, pick = pick, pock = pock, }, } -- Current fragilities: pushing a nil is a no-op; -- and pick and pock do not check depth. -- Beware: in dednat4 we stored the stack elements in the "wrong" -- order just to make pick and pock trivial to implement (tos was -- ds[1] in dednat4)... Now the conventions are: -- ds:pick(0) returns the tos ("top of stack") -- ds:pick(1) returns the element below tos -- ds:pock(0, "a") replaces the tos by "a" -- ds:pock(1, "b") replaces the element below tos by "b" --]==] ds = Stack {} -- (find-miniforthgempage 3 "DS={ 5 }") -- «MetaStack» (to ".MetaStack") -- (find-dn6 "diagforth.lua" "metastack") MetaStack = ClassOver(Stack) { type = "MetaStack", __tostring = function (s) return mytostring(s) end, __index = { ppush = function (ms) push(ms, #(ms.stack)) end, ppop = function (ms) popuntil(ms.stack, pop(ms)) end, metapick = function (ms, offset) return ms.stack[ms:pick(0) + offset] end, }, } depths = MetaStack {stack=ds, msg="Empty metastack"} -- «nodes» (to ".nodes") nodes = VerticalTable {} -- has numeric and string indices storenode = function (node) table.insert(nodes, node) node.noden = #nodes -- nodes[node.noden] == node if node.tag then -- was: "and not nodes[node.tag]"... nodes[node.tag] = node -- nodes[node.tag] == node end return node end -- «arrows» (to ".arrows") arrows = VerticalTable {} -- has numeric and string indices storearrow = function (arrow) table.insert(arrows, arrow) arrow.arrown = #arrows -- arrows[arrow.arrown] == arrow if arrow.tag then -- (unused at the moment) arrows[arrow.tag] = arrow -- arrows[arrow.tag] == arrow end return arrow end -- Local Variables: -- coding: utf-8-unix -- End: