通过lua自带例子学习lua 06 (26-30)

-- Example 26 -- Functions.

-- Define a function without parameters or return value.
function myFirstLuaFunction()
print("My first lua function was called")
end

-- Call myFirstLuaFunction.
myFirstLuaFunction()


-------- Output ------

My first lua function was called

-- Example 27 -- More functions.

-- Define a function with a return value.
function mySecondLuaFunction()
return "string from my second function"
end

-- Call function returning a value.
a=mySecondLuaFunction("string")
print(a)


-------- Output ------

string from my second function

-- Example 28 -- More functions.

-- Define function with multiple parameters and multiple return values.
function myFirstLuaFunctionWithMultipleReturnValues(a,b,c)
return a,b,c,"My first lua function with multiple return values", 1, true
end

a,b,c,d,e,f = myFirstLuaFunctionWithMultipleReturnValues(1,2,"three")
print(a,b,c,d,e,f)


-------- Output ------

1 2 three My first lua function with multiple return values
1 true

-- Example 29 -- Variable scoping and functions.

-- All variables are global in scope by default.

b="global"

-- To make local variables you must put the keyword 'local' in front.
function myfunc()
local b=" local variable"
a="global variable"
print(a,b)
end

myfunc()
print(a,b)


-------- Output ------

global variable local variable
global variable global

-- Example 30 -- Formatted printing.

-- An implementation of printf.

function printf(fmt, ...)
io.write(string.format(fmt, ...))
end

printf("Hello %s from %s on %s\n",
os.getenv"USER" or "there", _VERSION, os.date())


-------- Output ------

Hello there from Lua 5.1 on 04/06/13 16:16:02