Since redis + lua can do a distributed lock it simple to learn, I feel a bit like grammar and python
Scripted Programming
We can Lua holding program code to a file ending lua and performs the programming mode is called a script, such as the following code will be stored in a script file named hello.lua of:
print("Hello World！")
Use the above script lua executive, output is:
Note
Single-line comments
Minus two is a single line comment:
--
Multi-line comments
- [[ multi-line comment multi-line comments -]]
Identifier
Lua identifier used to define a variable, user-defined functions for additional items. After the identifier to a letter A to Z a to z, or the beginning or underscore _ plus zero or more letters, digits, (0 to 9).
Best not to increase the use underscores to write letters identifier, because Lua reserved words is the same.
Lua is not allowed to use special characters such as @, $, and% defined identifier. Lua is a case-sensitive programming language. Therefore, in Lua Runoob with runoob are two different identifiers. Here are some correct identifier:
mohd zara abc move_name a_123
myname50 _temp j a23b9 retVal
Key words
Following is a list of reserved keywords Lua. Keywords can not be retained as a constant or variable or other user-defined identifier:
| and | break | do | else |
| elseif | end | false | for |
| function | if | in | local |
| nil | not | or | repeat |
| return | then | true | until |
| while | goto |
The general convention, begin with an underscore connection string of uppercase letters the names (such as _VERSION) are reserved for internal Lua global variables.
Global Variables
By default, variables are always considered to be global.
Global variables need not be declared, after assignment to a variable creates a global variable, access does not initialize a global variable will not go wrong, but the results obtained are: nil.
print(b) b=10 print(b)
If you want to delete a global variable, simply assign values to variables is nil.
Such variable b as if the same had never been used. In other words, if and only if a variable is not equal to nil, this variable that is present.
