Lua golfing manual

This manual is a work-in-progress guide for code-golfing in Lua. It assumes you're already proficient with the language.

Practices to shorten

These practices usually make code shorter. Do these if applicable, and of course, only if shorter.

Minimize whitespace

This should go without saying, but minimize whitespace (spaces, tabs, newlines). More in Omit whitespace.

-- instead of:
while true do
	if (...) then
		(...)
	else
		(...)
	end
end
-- do this:
while true do if (...) then (...) else (...) end end
-- or even this:
while''do if (...) then (...) else (...) end end

Put statements on one line

Lua can parse multiple statements on one line without a semicolon. Taking advantage of omitting whitespace, this can chop a character or two.

-- instead of:
print('this')
print('that')
-- do this:
print('this') print('that')
-- or even this:
print('this')print('that')

Use global variables

-- instead of:
local x=1
-- do this:
x=1

Rename functions

Rename functions to one-letter variables.

-- instead of:
print('this')print('that')print('those')
-- do this:
p=print p('this')p('that')p('those')

Use short single-argument function call syntax

-- instead of:
print('this')print('that')print('those')
-- do this:
p=print p'this'p'that'p'those'

Omit whitespace

Many tokens don't need whitespaces after them to seperate them from others. Here is a list;

• (, )
• {, }
• [, ]
• ', "
• ...

...and there are these ones, but you probably know them already; #, %, &, *, +, ,, -, ., .., /, //, :, <, <=, =, ==, >, >=, ^, |, ~, ~=.

-- instead of:
if y then print ('yes') else print ('no') end
-- or:
if y then print('yes') else print('no') end
-- do this:
if y then print('yes')else print('no')end
--                   ^^              ^^
--       Notice how there's no whitespace.
-- or even this:
if y then print'yes'else print'no'end

Use the ternary operator

Use an and/or ternary expression instead of an if statement.

-- instead of:
if x then a=y else a=z end
-- do this:
a=x and y or z

Shorter ways to do common tasks

Truthy and falsy

Truthy

• any number, including 0
• empty string
• empty table

Falsy

• nil (a.k.a. undeclared variable)

Infinite loop

while''do
while""do
while{}do (...) end