411 REFERENCE · Wikibooks
Lua Programming/comment
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
Comments are pieces of text or whitespace that can be included in a program to make the code more understandable to a programmer. Comments have no effect on the running program and are ignored by the lua interpreter.
Comments start with a doublehyphen
In lua, comments start with a doublehyphen and run until the end of the line:
-- This is a comment
print "Hello World!"
Block comments
Block comments start with doubleshovel and run until doubleclosebox:
--[[Comments can be spread
across several lines ]]
print "Hello World!"
Enabled code within comments
By adding a hyphen to a doubleshovel to form a long handled doubleshovel, this enables code within the comment to become enabled, rather than commented out:
---[[The long handled doubleshovel means that this code will run
print "This will print because it is not a comment!"
-- We can still include comments by prefixing them with a doubledash
-- print "This will not print because it is commented out"
]]
Nested comments
A limitation of block style comments is that it is not possible to nest existing code containing comments without stripping the doubleshovel and doubleclosebox symbols from the nested code:
--[[
This will not work. Nesting of comment blocks will cause a syntax error.
--[[
By nesting existing code containing a comment, a syntax error will occur. This is because the nested symbols will confuse the interpreter, so a modification is required to remove the symbols
]]
print "Hello"
]]
The code needs modification as follows:
--[[
The nested comment block markers have been removed
@ This existing comment has had its block markers removed to prevent a syntax error
@
print "Hello"
]]