STYLE.LUA(9)

NAME
style.lua - FreeBSD lua file style guide

DESCRIPTION
This file specifies the preferred style for lua source files in the FreeBSD source tree. Many of the style rules are implicit in the examples. Be careful to check the examples before assuming that style.lua is silent on an issue.

The copyright header should be a series of single-line comments. Use the single-line comment style for every line in a multi-line comment.

After any copyright header, there is a blank line, and the $FreeBSD$ comment for non-C/C++ source files.

The preferred method of including other files and modules is with require(name), such as:

    -- $FreeBSD: releng/12.0/share/man/man9/style.lua.9 333419 2018-05-09 16:52:28Z kevans $
    config = require("config");
    menu = require("menu");
    password = require("password");
    -- One blank line following the module require block

include() is generally avoided.

Indentation and wrapping should match the guidelines provided by style(9). Do note that it is ok to wrap much earlier than 80 columns if readability would otherwise suffer.

Where possible, s:method(...) is preferred to method(s, ...). This is applicable to objects with methods. String are a commonly-used example of objects with methods.

Testing for nil should be done explicitly, rather than as a boolean expression. Single-line conditional statements and loops should be avoided.

local variables should be preferred to global variables in module scope. internal_underscores tend to be preferred for variable identifiers, while camelCase tends to be preferred for function identifiers.

If a table definition spans multiple lines, then the final value in the table should include the optional terminating comma. For example:

    -- No terminating comma needed for trivial table definitions
    local trivial_table = {1, 2, 3, 4}
    local complex_table = {
    	{
    		id = "foo",
    		func = foo_function, -- Trailing comma preferred
    	},
    	{
    		id = "bar",
    		func = bar_function,
    	},	-- Trailing comma preferred
    }

This reduces the chance for errors to be introduced when modifying more complex tables.

Multiple local variables should not be declared and initialized on a single line. Lines containing multiple variable declarations without initialization are ok. Lines containing multiple variable declarations initialized to a single function call returning a tuple with the same number of values is also ok.

Initialization should be done at declaration time as appropriate.

SEE ALSO
style(9)

HISTORY
This manual page is inspired from the same source as style(9) manual page in FreeBSD.