V-Gears LUA Style Guide

For the C++ Style Guide, see the V-Gears C++ Style Guide

TL;DR;

Readability over performance.
Be consistent whit existing code.
When in doubt, use the simplest solution.

Introduction

While most of the project core is C++, some scripts use LUA as a lenguage. This is a style guide for those scripts.

Note: This guide applies to manually writen code. Code automatically produced from the installer by parsing the game data should, as much as possible, follow these rules, but it's not mandatory.

Formatting

Indentation - Indenting uses four spaces. Don't use tabs.

for i,v in ipairs(t) do
    if type(v) == "string" then
        print(v)
    end
end

Naming

Variable name length - Variable names with larger scope should be more descriptive than those with smaller scope. For example, i is probably a poor choice for a global variable in a large program, but it's perfectly fine as a counter in a small loop.

Variable naming - Variables holding values or objects must be lowercase and short (e.g. color). Multiple words must be separated by underscores (e.g. front_color)

Function naming - Function names use PascalCase.

Constants naming - Constants, particularly ones that are simple values, are often given in ALL_CAPS, with words separated by underscores.

Module/package naming - Module names are all lowercase, with nothing between words.

Class names Should be PascalCase.

##Scope

Use locals rather than globals whenever possible.

local x = 0
local function count()
    x = x + 1
    print(x)
end

Globals have larger scopes and lifetimes and therefore increase complexity.

End terminator

Always use end as a block terminator

for i, v in ipairs(t) do
    if type(v) == "string" then
        -- ...lots of code here...
    end -- if
end -- for

lua

Commenting

Use a space after --.

return nil  \-- not found    (suggested)
return nil  \--not found     (discouraged)

Kepler sometimes uses this doxygen/Javadoc-like style:

-- taken from cgilua/src/cgilua/session.lua ------------------------------------- -- Deletes a session. -- @param id Session identification. ------------------------------------- function delete (id)

    assert (check\_id (id))
    remove (filename (id))

end

Code Documentation

Document every block of code with JavaDoc-style docstrings, for doxygen, like this:

--[[
 Retrieves a bit variable.
 @param bank Memory bank (0-index, as in game).
 @param variable Bank address (0-index, as in game).
 @param bit Address bit (0-index, as in game).
 @return 1 or 0
]]
bit = function(bank, variable, bit)
    return FFVII.BitBanks[bank + 1][variable + 1][bit + 1]
end

Lua Idioms

To test whether a variable is not nil in a conditional, it is terser to just write the variable name rather than explicitly compare against nil. Lua treats nil and false as false (and all other values as true) in a conditional:

local line = io.read()
if line then  \-- instead of line ~= nil
    -- ...
end
...
if not line then  \-- instead of line == nil
    -- ...
end

Credits

This file is derived from the style guide in Lua-Users. While some rules are completly different, the document structure, several paragraphs and many examples are original or closely derived.

STYLE-LUA.md 3.6 KB Cronologia Originale