下面是对 Lua 语言基本概念的简要概况。
查看 Lua 编程指南的第 1-5 章，了解更多详细信息。
注释
--A comment
--[[ A
comment block
]]
变量
local var1 -- Declaring a variable
local var2; -- Semicolon to end a statement (chunk) is optional
local var3 = nil -- nil is the default value for all uninitialized variables - similar to null in other languages
local VaR4 = "AbC" -- variables and strings are case-sensitive
local var5 = {} -- Declaring an array (a.k.a table)
保留的名称
and break do else elseif
end false for function if
in local nil not or
repeat return then true until
while
变量类型
local string = "Hello world"
local number = 10
local number2 = 10.4
local boolean = true
local function = type()
字符串中的逃逸字符
local string = "one line\nnext line\n\"in quotes\", 'in quotes'"
表 - 类似于其他语言中的数组
local a = {} -- create a table
local a = {1,2,3} -- accessed as a[1]=1, a[2]=2, a[3]=3
local a = {one=1,two=2,three=3} -- accessed as a["one"]=1, a["two"]=2, a["three"]=3 or a.one=1, a.two=2, a.three=3
-- items are placed starting at [1] position when declaring like this
local a = {"one","two","three"} -- accessed as a[1]="one", a[2]="two", a[3]="three"
-- replacing array items
a[1] = "four"
a["x"] = "string"
a["y"] = 5
运算符优先顺序
^ (exponential)
not - (unary operator)
* /
+ -
.. (concatenation)
< > <= >= ~= == (relational operators)
and (boolean operator)
or (boolean operator)
括号控制优先顺序
(a+i) < ((b/2)+1)
串接
local b = "Hello ".."World"
local b = 0 .. 1 -- spacing required for numbers
多重赋值
a,b = 1,2
a,b = f() -- functions can return multiple results
If/then/else
if a<0 then a = 0 end
if a<b then return a else return b end
循环结构
local i = 1
while a[i] do
print(a[i])
i = i + 1
end
循环
for i=1,f(x) do dw.log.exception("INFO",i) end
for i=10,1,-1 do dw.log.exception("INFO",i) end
-- log all values of array 'a'
for i,v in ipairs(a) do dw.log.exception("INFO",v) end