fluffos/docs/lpc/source-files.md

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source files & object names

Source files and object names

LPC source files use the .lpc extension; the legacy .c extension is fully supported. This page describes how a name like "/std/room" (or "/std/room.c", or "/std/room.lpc") is resolved to a source file and to a loaded object.

Resolution rules

When the driver needs to load a file — load_object(), an inherit statement, clone_object() of an unloaded name, the master or simul_efun file from the config — it resolves the source like this:

• An explicit extension is exact. load_object("/foo.c") probes only foo.c; load_object("/foo.lpc") probes only foo.lpc. The other spelling is never looked up.
• Extension-less names prefer .lpc, then fall back to .c. load_object("/foo") loads foo.lpc if it exists, otherwise foo.c.
• If no source file matches, the master's compile_object() apply is consulted with the extension-less name (the virtual object hook). If it declines, the load fails and load_object() returns 0.

Object names never carry an extension

A loaded object's name (what file_name() / base_name() return, and what the object registry is keyed by) is always the extension-less path: loading /std/room.lpc produces the object /std/room.

Consequently object identity is extension-blind:

• find_object("/foo"), find_object("/foo.c") and find_object("/foo.lpc") all find the same loaded object.
• load_object() consults the registry before the filesystem: any spelling of an already-loaded object's name returns that object; the exactness rule above only applies when the load actually reaches the disk.

The program name (prog->filename) is different: it records the real file that was compiled, extension included. That is the name reported by inherit_list(), deep_inherit_list(), error tracebacks, and compiler diagnostics.

object ob = load_object("/std/room");      // loads /std/room.lpc
file_name(ob);                             // "/std/room"
inherit_list(ob);                          // ({ "/std/container.lpc" })

Writing portable mudlib code

• Refer to objects by their extension-less name in normal code ("/std/room"); use an explicit extension only when you really mean a specific file.
• Do not append ".c" to names before calling load_object() / call_other() — pass the name through and let the driver resolve it.
• When comparing against program names (e.g. results of function_exists() on file paths, inherit_list() entries), expect either extension.

The full behavior is pinned by the driver test testsuite/single/tests/efuns/dual_extension.lpc.