A way to write switch-case statements in lua.

switch.lua

print "Hello, switch"

-- Suppose we want to write the equivalent lua code of the following c code:
-- switch (a) {
-- case 1:
--   printf("Case 1.\n");
--   break;
-- case 2:
--   printf("Case 2.\n");
--   break;
-- case 3:
--   printf("Case 3.\n");
--   break;
-- default:
--   printf("Case default.\n");
-- }
local cases = {
	[1] = function()	-- for case 1
		print "Case 1."
	end,
	[2] = function()	-- for case 2
		print "Case 2."
	end,
	[3] = function()	-- for case 3
		print "Case 3."
	end
}

local a = 4
local f = cases[a]
if (f) then
	f()
else				-- for case default
	print "Case default."
end

-- If the default case does not have to be handled, we can use the following auxiliary function:
local function switch(value)
  -- Handing `cases` to the returned function allows the `switch()` function to be used with a syntax closer to c code (see the example below).
  -- This is because lua allows the parentheses around a table type argument to be omitted if it is the only argument.
  return function(cases)
    local f = cases[value]
    if (f) then
      f()
    end
  end
end

local x = 2
switch (x) {
	[1] = function()	-- for case 1
		print "Case 1."
	end,
	[2] = function()	-- for case 2
		print "Case 2."
	end,
	[3] = function()	-- for case 3
		print "Case 3."
	end
}

Useful

I use this small function:

_G.switch = function(param, case_table)
    local case = case_table[param]
    if case then return case() end
    local def = case_table['default']
    return def and def() or nil
end

usage:

switch(a, { 
        [1] = function()	-- for case 1
		print "Case 1."
	end,
	[2] = function()	-- for case 2
		print "Case 2."
	end,
	[3] = function()	-- for case 3
		print "Case 3."
	end
})

noice.

really cool ad usefull

super usefull, thx

Didn't know this was a thing, helped a lot

This looks great. Can you add some comments to your code to help novices like me understand the lua chunk?

Awesome, thanks

Thank you.

@switch.lua Thank you.