====== Creation Law — Shops ======
 You know classic Diku shop tables / ''sedit''. Neo has **no** ''sedit''. A shop is a workspace prototype keyed by an existing **mobile VID**, edited with ''@shop …'', reviewed with ''@examine shop'', then committed with ''@save shop''.

Hub: [[immortal:creationlaw|Creation Law]]. Build the keeper mobile first: [[immortal:creationlaw:mobiles|Mobiles]]. Place it: [[immortal:creationlaw:zones|Zones]]. Player-facing buy/list/auction flow: [[player:gamelaw:shopkeepers|Shopkeepers]].

===== Why a shop is not the mobile =====
 The mobile is the body players talk to. The **shop** row (H2 table ''shopkeeper'') is the trade config: home room, produce list, item types traded, hours, and keeper messages. When a mobile has ''Acts.SHOPKEEPER'', runtime looks up ''ShopkeeperDB.at(mobile.vid())''.

So the build order is: **mobile (with SHOPKEEPER)** → **shop workspace on that same VID** → **zone place** → ''zone reset''. Creating ''@new shop'' before the mobile exists fails. Forgetting the Acts flag leaves a shop row that never handles ''list'' / ''buy''.

===== Prerequisites =====
  * An ''npc'' prototype already ''@save''d (same VID you will use for the shop)
  * On ''npc_stats'': ''@npc_stats flags acts shopkeeper'' (and usually ''sentinel'' so the keeper stays put)
  * A room that already exists for ''@shop room''
  * Item prototypes you intend to ''produces'' (optional slots — up to 10)

===== Step-by-step: first shop =====
**1. Confirm the mobile** (build it if needed — [[immortal:creationlaw:mobiles|Mobiles]]):

<code mud>
> @load npc_stats 1210
Okay.
> @npc_stats flags acts shopkeeper
Okay.
> @npc_stats flags acts sentinel
Okay.
> @examine npc_stats
> @save npc_stats
Okay.
>
</code>

**2. Open the shop draft** — VID **is** the mobile VID (must be in your mobile range; mobile must exist; no second shop draft while one is open):

<code mud>
> @new shop 1210
Okay.
>
</code>

Echoes you will see on failure (exact Immortality strings):
  * ''A new shop entry already exists in your buffer.'' — ''@examine shop'' then ''@save shop'' or ''@clear shop''
  * ''A shop already exists for that <mobile-vid>.''
  * ''No mobile with vid <n> exists.''
  * ''That vid is not in your range.''
  * Bad usage line in code prints ''@new show <mobile-vid>'' (typo for ''@new shop'').

**3. Home room** (why: ''Shopkeeper.check'' refuses ''@save'' when room is 0 — the room VID must already exist in ''RoomDB''):

<code mud>
> @shop room 1200
Okay.
>
</code>

**4. What the keeper trades** (''ItemType'' flags via ''@shop trades''; prefix ''!'' to clear when the modifier supports it). At least **one** type is required to save:

<code mud>
> @shop trades weapon
Okay.
> @shop trades armor
Okay.
>
</code>

Bare ''@shop trades'' reprints ''@shop trades (!)<flag>'' plus the ''ItemType'' list from code.

**5. Produce list** (optional but usual — stock the keeper lists / sells at a fixed cost). Positions **1–10** (''Shopkeeper.MAX_PRODUCES''). Cost must be ≥ 1 gold for any filled slot or ''@save'' returns ''producing vid:… for 0gc'':

<code mud>
> @shop produces 1 3100 500
Okay.
> @shop produces 2 3101 50
Okay.
>
</code>

Syntax: ''@shop produces <pos> <item-vid> <cost>''. The produce setter does **not** verify the item prototype exists at edit time — ''@examine'' shows ''ItemDB.proper'' when the item is known.

**6. Hours** — ''hours1'' is **required** to save (''open1'' must be non-zero). Both start and finish for ''hours1'' must be positive integers, and start must be strictly less than finish. ''hours2'' is optional and may only be set after ''hours1'':

<code mud>
> @shop hours1 8 12
Okay.
> @shop hours2 14 20
Okay.
>
</code>

**7. Keeper messages** (one-line writers — all six are required by ''Shopkeeper.check'' before ''@save''):

<code mud>
> @shop keeper_no_item_msg
I do not have that item.
> @shop customer_no_item_msg
You do not seem to have that.
> @shop customer_no_cash_msg
You cannot afford that.
> @shop keeper_no_buy_msg
I do not buy that sort of thing.
> @shop keeper_buy_msg
That will be %d coins.
> @shop keeper_sell_msg
Sold.
>
</code>

''keeper_buy_msg'' is passed through ''String.format(..., price)'' on several buy paths — include a ''%d'' where you want the gold amount echoed (same idea as the default string in ''S.keeperBuyMsg'').

**8. Review and commit:**

<code mud>
> @examine shop
--- Shop ---
MOBILE  : 1210
ROOM    : 1200
HOURS1  : 8 to 12
HOURS2  : 14 to 20
--- produces ---
...
--- trades ---
...
--- keeper has no item ---
...
> @save shop
Okay.
>
</code>

If ''@save'' returns a short error from ''Shopkeeper.check'', fix the field and save again — the draft stays open until save succeeds or you ''@clear shop''. Exact check strings include: ''no room is set''; ''no item types are set''; ''no customerNoItemMsg set'' (also returned when ''keeper_no_item_msg'' is missing — code quirk); ''no customerNoCashMsg set''; ''no keeperNoBuyMsg set''; ''no keeperBuyMsg set''; ''no keeperSellMsg set''; ''open time must be set''; ''producing vid:<n> for 0gc''.

===== Place the keeper via a zone =====
 Why: the shop row alone does not spawn the mobile. Zone reset loads the npc into a room; players then use ''list'' / ''buy'' / ''auction'' / … against that keeper ([[player:gamelaw:shopkeepers|Shopkeepers]]).

<code mud>
> @load zone 1299
Okay.
> @zone npc 1210 1200
Okay.
> @examine zone
> @save zone
Okay.
> zone reset
Okay.
>
</code>

===== ''@shop'' field commands =====
 From ''ModifySocial.cmdCrShop'' (real subcommands only):

  * ''room <room-vid>'' — home / shop room (room must exist)
  * ''produces <pos> <item-vid> <cost>'' — produce slot 1–10
  * ''trades (!)<ItemType>'' — types the keeper will handle
  * ''keeper_no_item_msg'' — one-line writer
  * ''customer_no_item_msg'' — one-line writer
  * ''customer_no_cash_msg'' — one-line writer
  * ''keeper_no_buy_msg'' — one-line writer
  * ''keeper_buy_msg'' — one-line writer (often with ''%d'')
  * ''keeper_sell_msg'' — one-line writer
  * ''hours1 <start> <finish>'' — required window
  * ''hours2 <start> <finish>'' — optional second window

Workspace companions (same pattern as rooms/items): ''@new shop'', ''@examine shop'', ''@clear shop'', ''@save shop'', ''@load shop <vid>'', ''@destroy shop <vid>''.

===== Edit an existing shop =====
<code mud>
> @load shop 1210
Okay.
> @shop produces 1 3100 450
Okay.
> @examine shop
> @save shop
Okay.
>
</code>

===== Vs classic shop OLC =====
 You never enter a numbered shop editor. There is no ''sedit''. You open a ''shop'' workspace on a **mobile VID**, set fields with ''@shop'', ''@examine'', ''@save''. Trade behavior also needs ''Acts.SHOPKEEPER'' on the mobile and a zone placement.

===== Common mistakes =====
  * ''@new shop'' before the mobile prototype exists
  * Mobile without ''flags acts shopkeeper''
  * Second ''@new shop'' while a shop draft is still open
  * ''@save shop'' without ''room'', trades, ''hours1'', or all six messages
  * Produce cost 0 on a filled slot
  * Building the shop but never ''@zone npc'' + ''zone reset''
  * Expecting ''redit''-style menus — workspace only

===== Code notes / gaps =====
 Documented as facts from the Java tree (not guesses):
  * Help-string typos: ''createNewShop'' usage prints ''@new show <mobile-vid>''; bad ''produces'' args print ''@new shop produces …''; ''deleteShop'' usage prints ''@delete shop'' while the verb is ''@destroy''; ''@destroy'''s usage line **omits** ''shop'' even though the handler accepts it.
  * ''Shopkeeper.check'': when ''keeper_no_item_msg'' is missing it still returns ''no customerNoItemMsg set'' (copy/paste quirk).
  * ''hours2'' validation message says "ahead of the open1 finish-hour" but the comparison uses ''open1()'' (the start).
  * Runtime (quick scan of ''MobileScript''): ''trades'', ''produces''/''cost'', ''keeper_no_item_msg'', ''keeper_no_buy_msg'', and ''keeper_buy_msg'' are used. ''room'', ''hours1''/''hours2'', ''customer_no_item_msg'', ''customer_no_cash_msg'', and ''keeper_sell_msg'' are **required to save** and stored, but no call sites were found that gate trading on hours/room or speak those three messages — treat as save requirements / future hooks unless you prove otherwise in a later code pass.

===== Related =====
  * [[immortal:creationlaw:mobiles|Mobiles]] — SHOPKEEPER act, npc layers
  * [[immortal:creationlaw:zones|Zones]] — place the keeper
  * [[immortal:creationlaw:objects|Objects]] / [[immortal:creationlaw:items|Items]] — produce VIDs
  * [[player:gamelaw:shopkeepers|Shopkeepers]] — player ''list'' / ''buy'' / ''auction'' / ''offer'' / ''value'' / ''identify''
  * [[immortal:creationlaw|Creation Law]] — hub