replace hellhole.cpp with hfs-pit.lua

A port/update.  May not have great argument handling, and there's a few
magic numbers, but it's a huge improvement over a non-compiling plugin.

NEWS

@@ -7,6 +7,7 @@ DFHack Future
     New Scripts
         position: Reports the current date, time, month, and season, plus
             some location info.  Port/update of position.py
+        hfs-pit: Digs a hole to hell under the cursor.  Replaces needs_porting/hellhole.cpp
     Misc Improvements
         further work on needs_porting
 

Readme.rst

@@ -2329,6 +2329,20 @@ For example, to grow 40 plump helmet spawn::
 
     growcrops plump 40
 
+hfs-pit
+=======
+Creates a pit to the underworld at the cursor.
+
+Takes three arguments:  diameter of the pit in tiles, whether to wall off
+the pit, and whether to insert stairs.  If no arguments are given, the default
+is "hfs-pit 1 0 0", ie single-tile wide with no walls or stairs.
+
+    hfs-pit 4 0 1
+    hfs-pit 2 1 0
+
+First example is a four-across pit with stairs but no walls; second is a
+two-across pit with stairs but no walls.
+
 lever
 =====
 Allow manipulation of in-game levers from the dfhack console.

needs_porting/_notes.txt

@@ -3,10 +3,6 @@ TODO:
         high value target - a proof of concept plugin to allow copy-pasting in DF; does both terrain and buildings/constructions
     creaturemanager.cpp
         modify skills and labors of creatures, kill creatures, etc; impressive but I suspect most functions implemented elsewhere
-    dfbauxtite.cpp
-        changes material of mechanisms to bauxtite (ie magma-safe)
-    hellhole.cpp
-        instantly creates a hole to the HFS
 
 In progress:
     hotkey-notes.lua

scripts/hfs-pit.lua

@@ -0,0 +1,88 @@
+-- Creates a pit under the target leading straight to the Underworld.  Type '?' for help.
+-- Based on script by IndigoFenix, @ https://gist.github.com/IndigoFenix/8776696
+
+args={...}
+
+if args[1] == '?' then
+    print("Example usage:  'hfs-pit 2 1 1'")
+    print("First parameter is size of the pit in all directions.")
+    print("Second parameter is 1 to wall off the sides of the pit on all layers except the underworld, or anything else to leave them open.")
+    print("Third parameter is 1 to add stairs.  Stairs are buggy; they will not reveal the bottom until you dig somewhere, but underworld creatures will path in.")
+    print("If no arguments are given, the default is 'hfs-pit 1 0 0', ie single-tile wide with no walls or stairs.")
+    return
+end
+
+pos = copyall(df.global.cursor)
+size = tonumber(args[1])
+if size == nil or size < 1 then size = 1 end
+
+wallOff = tonumber(args[2])
+stairs = tonumber(args[3])
+
+--Get the layer of the underworld
+for index,value in ipairs(df.global.world.cur_savegame.map_features) do
+    local featureType=value:getType()
+    if featureType==9 then --Underworld
+        underworldLayer = value.layer
+    end
+end
+
+if pos.x==-30000 then
+    qerror("Select a location by placing the cursor")
+end
+local x = 0
+local y = 0
+for x=pos.x-size,pos.x+size,1 do
+    for y=pos.y-size,pos.y+size,1 do
+        z=1
+        local hitAir = false
+        local hitCeiling = false
+        while z <= pos.z do
+            local block = dfhack.maps.ensureTileBlock(x,y,z)
+            if block then
+                if block.tiletype[x%16][y%16] ~= 335 then
+                    hitAir = true
+                end
+                if hitAir == true then
+                    if not hitCeiling then
+                        if block.global_feature ~= underworldLayer or z > 10 then hitCeiling = true end
+                        if stairs == 1 and x == pos.x and y == pos.y then 
+                            if block.tiletype[x%16][y%16] == 32 then
+                                if z == pos.z then 
+                                    block.tiletype[x%16][y%16] = 56
+                                else 
+                                    block.tiletype[x%16][y%16] = 55 
+                                end
+                            else 
+                                block.tiletype[x%16][y%16] = 57 
+                            end
+                        end
+                    end
+                    if hitCeiling == true then
+                        if block.designation[x%16][y%16].flow_size > 0 or wallOff == 1 then needsWall = true else needsWall = false end
+                        if (x == pos.x-size or x == pos.x+size or y == pos.y-size or y == pos.y+size) and z==pos.z then
+                            --Do nothing, this is the lip of the hole
+                        elseif x == pos.x-size and y == pos.y-size then if needsWall == true then block.tiletype[x%16][y%16]=320 end
+                            elseif x == pos.x-size and y == pos.y+size then if needsWall == true then block.tiletype[x%16][y%16]=321 end
+                            elseif x == pos.x+size and y == pos.y+size then if needsWall == true then block.tiletype[x%16][y%16]=322 end
+                            elseif x == pos.x+size and y == pos.y-size then if needsWall == true then block.tiletype[x%16][y%16]=323 end
+                            elseif x == pos.x-size or x == pos.x+size then if needsWall == true then block.tiletype[x%16][y%16]=324 end
+                            elseif y == pos.y-size or y == pos.y+size then if needsWall == true then block.tiletype[x%16][y%16]=325 end
+                            elseif stairs == 1 and x == pos.x and y == pos.y then 
+                                if z == pos.z then block.tiletype[x%16][y%16]=56
+                                else block.tiletype[x%16][y%16]=55 end
+                            else block.tiletype[x%16][y%16]=32
+                        end
+                        block.designation[x%16][y%16].hidden = false
+                        --block.designation[x%16][y%16].liquid_type = true -- if true, magma.  if false, water.
+                        block.designation[x%16][y%16].flow_size = 0
+                        dfhack.maps.enableBlockUpdates(block)
+                        block.designation[x%16][y%16].flow_forbid = false
+                    end
+                end
+                block.designation[x%16][y%16].hidden = false
+            end
+            z = z+1
+        end
+    end
+end