FormatSpec

Interface Format Spec

The function/property prototypes are listed using the following format:

• The parameter types of function calls are declared inside the parentheses after the function name.
• Return value types for functions are specified after ==>.
• The types listed for properties indicate the return value for the __index metamethod (get: part), or the required value type for the __newindex metamethod (set: part). The only valid type for keys is string for both metamethods. A dash (-) means that the property can't be read/written (but an inherited property of the same name might be used instead).
• Lua types are abbreviated as: nil=n, boolean=b, integer=i, number=d (think double), string=s, function=f, userdata=u, coroutine=c, table=t, any (non-nil)=a. Alternative types are concatenated together, so e.g. nu means nil or userdata.
• Parameters at the end of the parameter list which also accept nil can be left out as usual (optional parameters).
• Boolean parameters accept any Lua value (interpreted as true-ish/false-y as usual), so a boolean parameter at the end of the parameter list is optional as well.
• There are a few exceptions where the number of arguments is used to select an overloaded C++ method, but those cases are rare. Usually such functions are listed multiple times with different prototypes.
• Sometimes (groups of) optional arguments are explicitly marked using square brackets. In such a case you should provide none or all of the optional arguments.

If a function and a property have the same name, the function always takes precedence (hopefully the affected function or the property has been renamed to avoid this case), and methods/properties defined on the sub-class take precedence over inherited ones.