Configuration

Game configuration is held by the configuration daemon (CONFIG_D) and read everywhere through the mud_config() simul_efun. Settings live in LPML files using a cascading two-file pattern: shipped defaults plus local overrides that survive upgrades.

How It Works

CONFIG_D loads two files, in order:

File	Tracked in git?	Purpose
`adm/etc/default.lpml`	yes	Shipped defaults
`adm/etc/config.lpml`	no (`.gitignore`d)	Local overrides for your instance

The daemon reads default.lpml first to establish the baseline, then merges config.lpml on top. The merge is a shallow mapping addition (+=) — any top-level key in config.lpml replaces the same key from the defaults. Nested mappings replace as a whole; they do not deep-merge. Because your overrides live in a separate, untracked file, they are preserved across updates to the library.

Sensitive values — API tokens, webhooks, Discord/Grapevine credentials — belong in config.lpml, never in default.lpml.

Reading Configuration

Read any value with the mud_config() simul_efun. It is available everywhere with no #include:

string status = mud_config("OPEN_STATUS");

The key may be a flat top-level key ("PORT") or a dot-separated path into nested mappings, resolved via dot_walk. Prefer the dotted path over cracking open a returned sub-mapping at the call site — it keeps the schema inside the config layer:

// Preferred -- opaque key, single call:
int chance = mud_config("RESOURCE.GLOBAL_SPAWN_CHANCE");

// Avoid -- exposes the structure to the caller:
int chance = mud_config("RESOURCE")["GLOBAL_SPAWN_CHANCE"];

mud_config() raises an error for unknown keys, so do not call it speculatively. If a key might not exist, walk CONFIG_D->get_all_config() yourself instead.

Daemon API

CONFIG_D inherits STD_DAEMON and exposes:

Function	Signature	Purpose
`get_mud_config(key)`	`mixed get_mud_config(string key)`	Get one value by flat key or dot-path. `mud_config()` wraps this.
`get_all_config()`	`mapping get_all_config()`	Returns a copy of the entire config mapping.
`rehash_config()`	`void rehash_config()`	Reloads both files and re-merges. Runs automatically on startup.

Adding a Configuration Key

Add the default in adm/etc/default.lpml:
```
MY_NEW_KEY: "default_value",
```
Read it in code:
```
string val = mud_config("MY_NEW_KEY");
```
To override it locally, add the key to adm/etc/config.lpml (create the file if needed):
```
{
  MY_NEW_KEY: "local_override",
}
```

Keys are case-sensitive and uppercase by convention.

Rehashing at Runtime

After editing either file, reload without restarting the game by running the master admin command (which rehashes config among other reloads), or by calling CONFIG_D->rehash_config() directly. The mudconfig wizard command dumps the entire current configuration for inspection.

A Note on Driver Configuration

This system covers library configuration. Driver-level settings — ports, stack sizes, protocol toggles — are separate: they use get_config()/set_config() with constants from include/runtime_config.h and are not part of CONFIG_D.

Key Files

File	Role
`adm/daemons/config.c`	`CONFIG_D` — loads, merges, and serves configuration
`adm/simul_efun/system.c`	`mud_config()` simul_efun
`adm/etc/default.lpml`	Shipped default settings
`adm/etc/config.lpml`	Local overrides (not tracked)
`cmds/dev/mudconfig.c`	`mudconfig` command — dumps current config