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Control Flow

If / Elseif / Else​

if x > 0 then
    print("positive")
elseif x < 0 then
    print("negative")
else
    print("zero")
end

While Loop​

while condition do
    -- body
end

Repeat-Until Loop​

repeat
    -- body
until condition

Numeric For​

for i = 1, 10 do
    print(i)
end

for i = 0, 100, 5 do  -- with step
    print(i)
end

Generic For​

for k, v in pairs(tbl) do
    print(k, v)
end

for i, v in ipairs(arr) do
    print(i, v)
end

The compiler performs iteration type checking: when iterating over typed collections, loop variables are inferred. Enums are also iterable.

Do Block​

Creates a new scope:

do
    local temp = compute()
    -- temp is only visible here
end

Break​

while true do
    if done then break end
end

Labels & Goto​

::retry::
local ok = tryOperation()
if not ok then
    goto retry
end

Available on Lua 5.2+ and LuaJIT targets.