Use pathability groups (thanks @myk002) to detect stranded citizens

warn-stranded.lua

@@ -0,0 +1,46 @@
+-- Detects and alerts when a citizen is stranded
+-- by Azrazalea
+
+-- Taken from warn-starving
+local function getSexString(sex)
+  local sym = df.pronoun_type.attrs[sex].symbol
+  if not sym then
+    return ""
+  end
+  return "("..sym..")"
+end
+
+function doCheck()
+  local grouped = {}
+  local citizens = dfhack.units.getCitizens()
+
+  -- Pathability group calculation is from gui/pathable
+  for _, unit in pairs(citizens) do
+    local target = unit.pos
+    local block = dfhack.maps.getTileBlock(target)
+    local walkGroup = block and block.walkable[target.x % 16][target.y % 16] or 0
+    local groupTable = grouped[walkGroup]
+
+    if groupTable == nil then
+      grouped[walkGroup] = { unit }
+    else
+      table.insert(groupTable, unit)
+    end
+  end
+
+  local strandedUnits = {}
+
+  for _, units in pairs(grouped) do
+    if #units == 1 then
+      table.insert(strandedUnits, units[1])
+    end
+  end
+
+  print("Number of stranded: ")
+  print(#strandedUnits)
+  for _, unit in pairs(strandedUnits) do
+    print('['..dfhack.units.getProfessionName(unit)..'] '..dfhack.TranslateName(dfhack.units.getVisibleName(unit))..' '..getSexString(unit.sex)..' Stress category: '..dfhack.units.getStressCategory(unit))
+  end
+end
+
+doCheck()