Scaleform Studio Lua API Reference: package.loaders table reference
Description
A table used by require to control how to load modules.
Each entry in this table is a searcher function. When looking for a module, require calls each of these searchers in ascending order, with the module name (the argument given to require) as its sole parameter. The function can return another function (the module loader) or a string with mesaage about why the module is not found (or nil ). Lua initializes this table with four functions.
The first searcher simply looks for a loader in the package.preload table.
The second searcher looks for a loader as a Lua library, using the path stored at [package.path]. A path is a sequence of templates separated by semicolons. For each template, the searcher will change each interrogation mark in the template by filename, which is the module name with each dot replaced by a "directory separator"; then it will try to open the resulting file name. So, for instance, if the Lua path is the string "./?.lua;./?.lc;/usr/local/?/init.lua" the search for a Lua file for module foo will try to open the files ./foo.lua, ./foo.lc, and /usr/local/foo/init.lua, in that order.
The third searcher looks for a loader as a C library, using the path given by the variable package.cpath. For instance, if the C path is the string "./?.so;./?.dll;/usr/local/?/init.so" the searcher for module foo will try to open the files ./foo.so, ./foo.dll, and /usr/local/foo/init.so, in that order. Once it finds a C library, this searcher first uses a dynamic link facility to link the application with the library. Then it tries to find a C function inside the library to be used as the loader. The name of this C function is the string "luaopen_" concatenated with a copy of the module name where each dot is replaced by an underscore. Moreover, if the module name has a hyphen, its prefix up to (and including) the first hyphen is removed. For instance, if the module name is a.v1-b.c, the function name will be luaopen_b_c.
The fourth searcher tries an all-in-one loader. It searches the C path for a library for the root name of the given module. For instance, when requiring a.b.c, it will search for a C library for a. If found, it looks into it for an open function for the submodule; in our example, that would be luaopen_a_b_c. With this facility, a package can pack several C submodules into one single library, with each submodule keeping its original open function.
require (modname) : anyLoads the given module.
package.preloadA table to store loaders for specific modules (see require).
modname : stringThe name of the module.
anyThe value returned by the loader or an error meassage if a loader is not found.A string of characters.This value may be an instance of any type.Indicates a table.
This documentation uses the term table to mean an anonymous, temporary Lua table that contains named data values. You typically use these tables to pass data or settings to a function, or to hold data returned by a function.Indicates an object.
This documentation uses the term object to mean a named Lua table or userdata value that maintains a state. Some object types may have multiple instances existing at the same time, each with its own state; these objects typically have creation functions or accessors that you must call in order to get an instance. Some object types have only one instance, which you always access through the object's name.Indicates a named variable within a namespace, object or table; or an element within an enumeration.Indicates a code sample.Indicates an enumeration.
This documentation uses the term enumeration to mean a named Lua table that contains only a set of constant values. These values typically identify a predefined set of options for some setting or behavior. You might pass an enumeration value to a function, or test the value returned by a function against the items in the enumeration to see which option is currently set.Indicates a named variable within a namespace or object that has a pre-set constant value.Indicates a category: a semantic grouping of related API elements.Indicates a namespace.
This documentation uses the term namespace to mean a named Lua table that exists in only one single instance, intended as a container for an interface of related objects, functions and data variables.Indicates an output value returned by a function.Indicates a named function within a namespace or object.Indicates an input parameter for a function.