Fate/filter API

File filters in FPX are sandboxed lua scripts, used to provide advanced editing functionality to mods on deployment. The lua engine is 5.1.4 with functionality limited by the sandbox environment.

Of major note, a number of functions and libraries that provide access to the file system have been removed from the sandbox. Instead, as each filter script is ran as a function, the file's contents being accessed can instead be found using the ‘…’ ellipses variable. The contents are edited and then returned, and FPX will store the returned string as the new file contents (or pass them along to the next filter). If a non-string value is returned, it is discarded instead and the filter is skipped.

Sandbox API

Key	Type	Description
Tables in Sandbox's `_G`
_sandbox	Table	Self-references the sandbox's table.
user_config	Table	The user's `config.ini` file contents as a table.
modlist	Table	The user's current modlist data.
string	Library	Standard string library.
math	Library	Standard math library.
os	Library	Limited OS library (only contains `os.time` and `os.date`).
debug	Library	Limited debug library.
coroutine	Library	Standard coroutine library.
table	Library	Standard table library.
Functions in Sandbox's `_G`
spickle	Function	Visually represents the structure of a table as a string (for debugging).
print	Function	Quick formatted console print.
console_print	Function	Formatted print; provide your own logging level (1-4).
load	Function	Lua's `load()` function with sandbox limitations.
loadstring	Function	Lua's `loadstring()` function with sandbox limitations.
loadfile	Function	Lua's `loadfile()` function with sandbox limitations.
dofile	Function	Sandboxed `loadfile`, but with instant execution.
require	Function	require is a stub in the sandbox's context and has no functionality.
read_mod_file	Function	Reads a file relative to the user's mod directory.
read_game_file	Function	Reads a file relative to the user's game directory.
Additional Values in Sandbox's `_G`
…	String	Script mods read this string to get the contents of the file they are editing. Returning a string saves any edits made.