｛Lua｝语言版块

rubyish

moonscript 简洁比 lua

paktc

撸啊{:2_168:}

Perlvim

Hello all,
I am a new user of Lua, I want to learn Lua.

I found the newest version is 5.2.1, the newest version of windows installer is 5.1.4.

I found it have great change from 5.1.4 to 5.2.1. LuaJIT is a faster interpreter of LUA, but it only support 5.1.x.

I want to know LuaJIT would became an individual version of Lua or would upgrade and support to 5.2.1?

I am afraid MoonScript also could became an different language.

The declaration word of function is too long, If it would be shorter?
default variable declaration is global, but local variable is more faster, Why Lua use global variable as default declaration?

If have any observed word would be used as keyword of Lua in furture?

following code could not run yesterday, but it is worked before

local filename = 'perlvim.lua'
local fh = io.open(filename, 'r')
local text = io.read("*all")
print(text)

If have any same question occured someone else?

yybmsrs

回复 13# Perlvim


    c版有人熟悉lua，你可以@他们

http://bbs.chinaunix.net/thread-4054291-1-2.html

Monox

Perlvim 发表于 2012-12-07 12:41
default variable declaration is global, but local variable is more faster, Why Lua use global variable as default declaration?

following code could not run yesterday, but it is worked before

local filename = 'perlvim.lua'
local fh = io.open(filename, 'r')
local text = io.read("*all")
print(text)

Don't know what you mean by saying Lua use global variable as default declaration. It's a good practise to declare variables before using them, and when declaring them you should use local as most as you can.

Only you can use a variable before you declare them in lua, which makes it a global variable with a nil value, which is not desired at the most cases and should be avoided.

And one thing, assign a value to a variable is not the same as declare a variable. AFAIK, Lua only have one keyword for declare variables, which is 'local'.

Maybe you were thinking about something like following which works for me(Pay attention to the third line):

1. 
   
2. local filename = 'perlvim.lua'
   
3. local fh = io.open(filename, 'r')
   
4. local text = fh:read("*all")
   
5. print(text)
   

复制代码

Perlvim

yes, filehand:read is ok.

In moonscript, all the variable would be transfered to local

MoonScript:
for key, value in pairs(my_table) do
    -- do something
end

--> will transfer to
local key, value
for key, value in pairs(my_table) do
    --- do something
end

If We want use a global variable. how to declare it?

just like:
global var = 'stirng'

I think MoonScript should add a keyword to declare global variable, like 'our', 'var', or 'global' .. etc

我的意思是 关键字定义的问题：
定义一个函数的关键字是 function， 这个太长了，频繁使用的关键字应当短一些。
ruby, python 是 def, Perl 是 sub, Moonscript & CoffeeScript 用 -> 来做函数的声明字符。

Perlvim

在以下情形下，变量是局部的

1. 函数的参数声明是局部的 -> arg
function function_name(args)
    -- some expression
end

2. 循环的迭代参数 key, value
for key, value in pairs(my_table) do
    -- do something
endf

Perlvim

-- lua 不能处理 unicode 字符
-- lua 只能处理 1-255范围内的ASC字符

string.char(256) 会报错。

Perlvim

如何测试某个单词是Lua的关键字呢？

Lua 5.2.1增加了 goto 作为关键字，如何用一个脚本来测试这个变化呢？

Perlvim

想让你的程序的性能达到极致吗？请学习C语言吧