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- Subject: Newbie question list: Was The perverse vibe of lua-l
- From: Steve Litt <slitt@...>
- Date: Tue, 25 Jan 2011 03:05:03 -0500
On Tuesday 25 January 2011 02:24:34 Alexander Gladysh wrote:
> Maybe we should even enter newbie questions (along with answers) there
Excellent idea. Let me start it out, and we can keep adding to it.
Q: Why no continue?
A: It interferes with repeat/until, but there are many ways to get along
Q: Why doesn't #tablename give the number of entries?
A: Implementation detail, but no matter what number you want there's a way to
easily get it.
Q: How do you capitalize Lua?
A: Lua. Never LUA or lua.
Q: Why do my tables keep changing by themselves?
A: Tables are always passed and assigned by reference, so changing a table
within a function changes that same table in the function's caller.
Q: Why no arrays?
A: You can use tables for arrays by making the keys successive integers, and
Lua tables are optimized so that's pretty efficient.
Q: How do you do OOP in Lua?
A: Technically Lua doesn't have OOP, but you can simulate OOP to your hearts
content and it's every bit as good as the OOP they give you in other
languages. Three of many possible ways are 1) Tables, 2) Closures and 3)
Q: Is Lua fast?
A: You'd better believe it. Very fast for an interpreter.
Q: What's LuaJIT?
A: It's a pretty much drop-in compatible Lua interpreter, except it has no
interactive mode and it's much faster.
Q: How do I get Lua add-ons?
A: Either from your Linux distribution's package manager, or from Lua's
package manager LuaRocks, or ./configure;make/make install.
Q: LuaRocks search doesn't find a package I know is there. Why not?
A: The package is probably at a URL not known to LuaRocks. Use a search engine
to find the package URL and then put that URL in LuaRocks' --from= option. If
you typically find your using that URL a lot, add it to the rock_servers table
in your config.lua LuaRocks config file, probably in directory /etc/luarocks.
Q: How do I do database stuff with Lua?
A: The most common way is to use the LuaSQL addon. There are plenty of other
packages, depending on what you need.
Q: Why do my for loops do weird stuff?
A: Check to see if you're changing loop variables within the loop. That
creates undefined situations. Check to see whether you're doing adds or
deletions within your loop. That creates undefined situations.
Q: I don't understand iterators.
A: See http://www.lua.org/pil/6.1.html for the very beginning basics of
Well, that's all for tonight -- you guys add some stuff to it.
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