feat: add SaveGame.fnv1a32, migrateForward and Scavenging.herbFor

src/scavenging.lua

@@ -0,0 +1,64 @@
+-- A third way to spend a fresh corpse, alongside Game:butcherCorpse's meal
+-- and Game:raiseCorpse's thrall: carving it for the herb its own kind
+-- carries rather than for food or an undead ally, so a cauldron (see
+-- alchemy.lua) can draw on combat itself and not only on whatever the floor
+-- happened to scatter. Every wild faction maps to a fixed herb, so the same
+-- species always yields the same ingredient no matter which floor or seed
+-- felled it - a goblinoid's crude poultice weed is always bloodroot, a
+-- drake's scorched hide is always emberleaf. A corpse already past its rot
+-- threshold (see Corpses.isRotten) has nothing left worth carving, and one
+-- left behind by anything without a bestiary entry - a bonded companion or
+-- a hired ally, never a wild monster - carries no herb at all; the corpse
+-- itself is spent either way it fails, exactly like Corpses.butcher's own
+-- certain trade, this is a deliberate trade the autopilot never makes on
+-- its own (see Game:scavengeCorpse), the same way it never raises one.
+
+local Corpses = require("corpses")
+local Alchemy = require("alchemy")
+local Monsters = require("monsters")
+local Factions = require("factions")
+
+local Scavenging = {}
+
+Scavenging.HERB_BY_FACTION = {
+  [Factions.VERMIN] = Alchemy.NIGHTCAP,
+  [Factions.GOBLINOID] = Alchemy.BLOODROOT,
+  [Factions.ORCISH] = Alchemy.BLOODROOT,
+  [Factions.BEAST] = Alchemy.EMBERLEAF,
+  [Factions.CULT] = Alchemy.NIGHTCAP,
+  [Factions.DRAKE] = Alchemy.EMBERLEAF,
+  [Factions.BANDIT] = Alchemy.SUNPETAL,
+  [Factions.MERCHANT] = Alchemy.SUNPETAL,
+}
+
+-- The herb key `corpse` would yield, or nil when its species is unknown to
+-- the bestiary (a companion's or hireling's own remains) or belongs to a
+-- faction (UNDEAD is the only one) with nothing mapped above - moot in
+-- practice since Corpses.leavesCorpse already refuses the undead a corpse
+-- at all, kept here only so an unmapped faction fails closed rather than
+-- erroring.
+function Scavenging.herbFor(corpse)
+  local spec = Monsters.byKey[corpse.species]
+  local faction = spec and spec.faction
+  return faction and Scavenging.HERB_BY_FACTION[faction]
+end
+
+-- Carves `corpse` for its herb instead of food, spending it in one stroke.
+-- Refuses without spending anything when the corpse has already rotted past
+-- use or its species yields no known herb; returns (false, reason) in
+-- either case so a caller never has to re-derive why.
+function Scavenging.harvest(game, corpse)
+  if Corpses.isRotten(corpse) then
+    return false, "the corpse has rotted too far to yield anything worth carving"
+  end
+  local herbKey = Scavenging.herbFor(corpse)
+  if not herbKey then
+    return false, "there is nothing worth carving from this corpse"
+  end
+  Corpses.remove(game.level, corpse)
+  local herb = Alchemy.herb(herbKey)
+  game.player.inventory[#game.player.inventory + 1] = herb
+  return true, string.format("you carve a %s from the %s corpse", herb.name, corpse.name)
+end
+
+return Scavenging