10 ms·

Learn Lua in 15 Minutes

357 points by tylerneylon 13y ago

lukefreiler 13y ago
I love this. I'd like/pay to have a consistent library of exactly this for other languages.
- digitalsushi 13y ago
  A scripting language rosetta stone. Here's one http://www.lurklurk.org/rosetta.html http://www.lurklurk.org/rosetta.html
  - lukefreiler 13y ago
    Yes, this - but with more languages and in the format of this topic. Just a really easy read.
- makeset 13y ago
  Who's up for the C++ version? :)
digitalsushi 13y ago
Thanks! Lua is used all over the place in wireshark user scripts. This is super useful.
programminggeek 13y ago
I would like to say that the easiest way for me to learn lua really fast was to build games with Corona using lua. Having a great tool that gives great feedback right away makes learning a language more fun IMO.
- potomak 13y ago
  Almost the same experience but with Love2D[1] instead of Corona. After learning Lua I also suggest to take a look at MoonScript[2] a dynamic scripting language that compiles into Lua, you can think about it as the CoffeeScript of Lua. [1] http://love2d.org/ http://love2d.org/ [2] http://moonscript.org/ http://moonscript.org/
  - Tloewald 13y ago
    Codea (ios) is also nice. My first forays into Lua were hacking WoW UI components.
- jamesbritt 13y ago
  I got my feet wet with Lua by writing custom OSC handlers for Renoise. There were the expected "WTF?" moments but having something running and doing something practical is a great motivator.
- seclorum 13y ago
  Likewise! For me, it was MOAI: http://getmoai.com/ http://getmoai.com/ Since I became a Lua programmer, I really can't stand any other languages, and I've rapidly switched to it for my scripting needs. Tables are just soooo lovely. ;)
karpathy 13y ago
This is awesome. I will take [a single huge list of self-explanatory example snippets (with a few short comments here and there) for 95% of use cases] over [detailed walls-of-text docs pages spread across a hierarchy of topics] any day.
- tylerneylon 13y ago
  Thanks. My goal was to write the tutorial I wish I had when I started. Your description also matches my own preferred learning style.
  - StavrosK 13y ago
    Were you inspired by http://www.stavros.io/tutorials/python/ http://www.stavros.io/tutorials/python/, by any chance?
  - anoymous9352 13y ago
    Mine too. If I had found this back when I was learning Lua, I'm certain I'd have bookmarked it and referred to it regularly. I just hope beginners don't absorb the coding style too much >:)
- uniclaude 13y ago
  I'm glad this comment sits at the top of this thread. I do hope that more and more learning resources come to us in this form, which is a very good thing to give you an idea of wether you would like to jump into a language (or maybe even a framework/platform?). OP did a very good job. That said, Lua is quite the special case, as it does not require much time to get up and running with it. This is one of the reasons why it is the scripting language of Redis by the way (Antirez even wrote Total time require to master it enough? 5 minutes.[1] regarding building scripts for Redis). [1]:http://oldblog.antirez.com/post/scripting-branch-released.html http://oldblog.antirez.com/post/scripting-branch-released.ht...
- kemist 13y ago
  Can't agree with you more!
- 13y ago
piqufoh 13y ago
I love this - if every language could have something like this written up it would be amazing. It just about fits into my attention span!
- chubot 13y ago
  Well, it helps a lot that Lua is by design a very small language :) Python is actually much bigger nowadays -- I would challenge someone to come up with something this simple that doesn't leave out a lot of stuff you will encounter in real code. The extra features ("bloat") do matter. I like the idea of Lua a lot, but when I started programming in it, it unfortunately felt like a less capable Python to me.
  - TillE 13y ago
    Lua and Javascript are quite similar in that way: nice little languages that fall apart really quickly when you try building anything reasonably large or complex. I don't really understand the attraction, except in certain niches like Lua as an embedded scripting engine, when you really need something that can be trivially sandboxed.
    - landhar 13y ago
      > [...] except in certain niches like Lua as an embedded scripting engine, when you really need something that can be trivially sandboxed. Isn't that exactly the reason JavaScript exists in the first place (i.e.: an embedded scripting engine for browsers) ?
  - jnbiche 13y ago
    I'm sure you're aware of Penlight, which does a very nice job of providing a "batteries included" library similar to Python's for Lua.
    - untothebreach 13y ago
      I definitely wasn't, thanks for the tip!
outworlder 13y ago
This is awesome. On that note, I don't understand all the javascript craze. Lua has been around for quite some time, and it's small, with well-defined semantics, a nice set of features, the interpreter is small and very fast, you can get even faster with LuaJIT, etc. Browsers should have adopted that ages ago.
- fhd2 13y ago
  Yeah, I see Lua in many ways as "JavaScript done right". I also found it considerably easier to integrate than something like V8, and it appears to be easier to use for non-programmers. It definitely deserves to be more popular.
  - taproot 13y ago
    Javascript being used by non programmers is 95% of the problems with javascript.. care to explain your problems with js and maybe expand on how lua is done right?
    - ufo 13y ago
      Lua is a much smaller language and overall it is much more consistent and has less corner cases than Javascript since the language had the opportunity to evolve over the years instead of needing to retain backwards compatibility with browsers from 1995. For example: * Lua has proper lexical scoping instead of the confusing "function scoping" of Javascript (so there is no need to use the IIFEs hack). * Lua has a Python-style lexicaly scoped self instead of the error prone dynamically scoped "this". No need to use `var taht = this` if you have nested functions. * The metatable system is much more flexible than the simple JS prototypal inheritance system (you can sort of implement "method missing" instead of being forced to only delegate to a concrete table. * You can use anything as a Lua table key. In JS all keys are converted to strigns. Lua also supports weak references. * Coroutines! Its sort of like ES6 generators and is super awesome. Async programming is infinitely more pleasant in Lua than it currently is in JS because you don't need to convert code to continuation passing style.
    - fhd2 13y ago
nathas 13y ago
That was lovely. I always had a hard time wrapping my head around the exact behavior of metatables when I messed with Lua a few years back. Thanks!
nbouscal 13y ago
Obligatory: Teach Yourself Programming in Ten Years — http://norvig.com/21-days.html http://norvig.com/21-days.html
dave1010uk 13y ago
Along the same lines is http://hyperpolyglot.org/ http://hyperpolyglot.org/ (which has been posted here a few times). This is useful both for learning a new language and for a quick reference for languages you're not so hot on. It's also very interesting to compare similarities and how languages have influenced each other. It seems (from the comments here and my own experience) that many people really like this style of learning. It would be great to see it applied in more areas.
- adambard 13y ago
  I find the inline-commented version a bit easier to read and to reason about, personally.
- copx 13y ago
  Thanks for reminding me of Io.. not. I was so happy with Lua and thought it was such an elegant and clean language.. then I looked at the side-by-side comparison between Lua and Io on the site you linked.. and now it seems clumsy and ugly. Unfortunately a language is only as good as its implementation and tooling and Io's implementation is "experimental" at best (and development is pretty much dead) + the utter lack of tools and third-party support so I will have to stick with Lua.. and try very hard to forget Io again.
Dylan16807 13y ago
This is a neat little reference but I can't waste the opportunity. I've seen people say they've never seen complaints about fonts being too big? Well here I am, complaining that the fonts are so big this page is hard for me to read without zooming out.
jeltz 13y ago
Having a font size of 25.33pt makes the website impossible to read without zooming out 3 steps. I would be happy if people stopped using tiny and huge default font sizes.
- ricardobeat 13y ago
  You can zoom in/out as much as you'd like, as you already know, so there is no need to force your personal taste on everyone else.
- bananpermobil 13y ago
  Well, it looks very good and reads very good on my ipad and on my tiny screen on my notebook. Otherwise I would've to zoom in, not a big deal though, do you think?
sharkbot 13y ago
I'm going to be "that guy": -- These are the same: -- ...snip... local function g(x) return math.sin(x) end local g = function (x) return math.sin(x) end According to the Lua Reference Manual [1], this example isn't correct. Rather, this is the correct translation: local function g(x) return math.sin(x) end local g; g = function (x) return math.sin(x) end From the manual: "This only makes a difference when the body of the function contains references to f." [1] http://www.lua.org/manual/5.2/manual.html#3.4.10 http://www.lua.org/manual/5.2/manual.html#3.4.10
- anonymoushn 13y ago
  What this means in practice: > local g=function() print(type(g)) end g() nil > local function g() print(type(g)) end g() function
- tylerneylon 13y ago
  You're right; I fixed that part.
  - fab13n 13y ago
    you also miss a couple of "local newObj" in constructors.
hanjos 13y ago
Nice work! One nitpick: local function declarations, like local function g(x) return g(x) end are actually the same as writing local g; g = function (x) return g(x) end . Without that first local g; statement, local functions wouldn't be able to call themselves recursively.
- tylerneylon 13y ago
  yep; fixed
thyrsus 13y ago
First, that was very useful; bookmarked. That took me 30 minutes to read. I think I might feel like I've learned the language after spending 8 hours working the examples a la "Learn Python the Hard Way". Luckily, I'm not competing with the folks here that learned it within 15 minutes ;-).
- tylerneylon 13y ago
  The title is a bit optimistic :) That's how long it takes me to read as if I were reading a novel, which isn't quite fair. I wanted to express something like "hey, this guide is for programmers and is surprisingly short and easy to consume considering it covers the large majority of the language." The current title seemed a bit snazzier.
alecdbrooks 13y ago
A logical next step might be to do do the Lua Missions (read: koans): https://github.com/kikito/lua_missions https://github.com/kikito/lua_missions. (Disclaimer: The missions look good, but I haven't personally tried them.)
- jballanc 13y ago
  Actually, the Lua Missions are excellent! I highly recommend taking the time to work through them. More than just a series of exercises (like most of the foo-koans), there's actually a narrative and a larger lesson you can learn if you work through the full problem set.
  - otikik 13y ago
    Hi, Lua Missions author here! Thanks for the kind words. One word of warning though: I never got around to make one mission about coroutines. But I accept pull requests :)
daenz 13y ago
Lua can be great. I've worked with it extensively on a personal project, where I've embedded it in a C++ app. However, there are some things that you will hate: * Trying to correctly do "inheritance" * Having to write all of your batteries for common ops * Array indices begin at 1! * Poor debugging support Aside from those thing, Lua is great. It's crazy fast and easy to embed.
noonespecial 13y ago
I learned to love lua when writing basic sysadmin scripts for OpenWRT based systems. I had previously used perl for sysadmin stuff, but perl (even microperl) took too much space on OpenWRT boxes with 4MB flash drives. Lua to the rescue. Now I chafe when I have to go pack to perl. I do wish someone had handed me this on the first day I realized I needed lua.
landhar 13y ago
This is very cool, the only way I can see this could be improved upon is by adding unit tests somehow (so that you can catch behavior changes when upgrading to a newer version of lua).
- spc476 13y ago
  I'm not sure it's really necessary---Lua 5.0 came out in 2003, 5.1 in 2006 and 5.2 in late 2011. It doesn't change that fast.
silentbicycle 13y ago
This is a good start, but there's also some deeper ideas in Lua. It has a good implementation of coroutines, for example; if you're familiar with continuations from Scheme, they fit most of the same uses. (They're like generators from Python or fibers from Ruby, but with less edge cases.) The C interop is also a Big Deal. Lua seems like a cute little language, like a cleaner Javascript, but it's a LOT more useful if you're also proficient in C. Also, Lua will run anywhere you have an ANSI C compiler and a modest amount of space.
- chalst 13y ago
  Coroutines are tricky, and you need to explain them, not just present a bit of code. I think it is the right decision to omit them from a 15-minute intro. The C API is way out of scope. I would cover assert() statements and the common (exit_status, result) var return, since that is so idiomatic. Maybe also loading chunks.
  - silentbicycle 13y ago
    I agree, they're tricky. I'm currently working on a blog post about them. :)
ufo 13y ago
This would look much better with syntax highlighting.
spacecowboy 13y ago
That was a pretty cool crash course on Lua Tyler! Thanks for putting that together and sharing it. After having had worked with numerous languages over the years such as Fortran, Pascal, Ada, C, Java, C++, C#, Python and Objective-C, I must say that working with Lua is my favorite. I'm thankful to a buddy of mine for introducing it to me. My own personal experience has shown me that working with Lua really allows you to focus on solving the problem versus getting wrapped around the axle at the programming language level. Thanks again
mneary 13y ago
Anyone else catch the Gauss reference[1] in the for loop section? [1] http://en.wikipedia.org/wiki/Carl_Friedrich_Gauss#Anecdotes http://en.wikipedia.org/wiki/Carl_Friedrich_Gauss#Anecdotes
- makeset 13y ago
  Ha! I got karl, was wondering who fred was.
- tylerneylon 13y ago
  You have a keen eye for subtle references! I didn't expect many people to get that one :) There's another math anecdote reference hidden in there as well - probably even more obscure than Karl's sum.
  - tekacs 13y ago
    Upon reading this comment had to skim the whole thing looking for more (hadn't yet finished reading). No more maths references than tau found yet. :/
    - tylerneylon 13y ago
      Ramanujan and Hardy are two well-known mathematicians who collaborated in Britain between 1914 and 1920. One day Hardy took taxi number 1729 to visit Ramanujan, and remarked to him that he (Hardy) could think of nothing special about the number (1729). Ramanujan replied that it was in fact the first number expressible as the sum of two cubes in two different ways (1^3 + 12^3 = 9^3 + 10^3). The story has since become an anecdotal symbol of Ramanujan's brilliant mind. http://en.wikipedia.org/wiki/1729_(number) http://en.wikipedia.org/wiki/1729_(number) That's a very obscure reference, though, so I apologize for sending anyone looking based on my previous comment.
      - tekacs 13y ago
        Haha I'd heard this anecdote before, so it's my own fault for missing it. :) Thanks for the great article and indeed fun references!
dakimov 13y ago
Great sheet. -- Variables are global by default. thisIsGlobal = 5 -- Camel case is common. -- Undefined variables return nil. -- This is not an error: foo = anUnknownVariable -- Now foo = nil. -- Only nil and false are falsy; 0 and '' are true! Didn't read further. Bad language design. Must die.
- otikik 13y ago
  First two can be changed quite easily: http://metalua.luaforge.net/src/lib/strict.lua.html http://metalua.luaforge.net/src/lib/strict.lua.html The last one is awesome.
- seclorum 13y ago
  Bah! Why is it bad and why must it die? Please add content to this discussion - I don't agree with you, but maybe you can convince me. Try it.
- anonymoushn 13y ago
  Could you tell us anything about why these things are bad? Regarding the last point (the one that you cannot change), I'm not sure I prefer the behavior of any other language. In Python, for instance, all of the number-like things I tried were falsy iff they were 0, and I found that almost any container is falsy iff it is empty, but Queues are always truthy. This is a weird exception, and I would rather not have to remember it. Collections and numeric types defined in external libraries can easily have the same problem.
  - dakimov 13y ago
    Global automatically declared variables is a well-known bad feature of some non-modern languages that gives nothing but an opportunity to make hardly detectable mistakes because of misprints. Arbitrary nonsensical type casts must be prohibited. The compiler/interpreter/IDE must infer types and help the programmer to catch their mistakes as early as possible. As a general rule of language design, if something looks unintentional or ambiguous to a human, it should look so to a compiler/interpreter. The more coherent the programming environment is to your conscience, the easier the programming is.
johnchristopher 13y ago
Bonus point for Cloud Atlas reference :)
deleted 13y ago
[deleted]
daGrevis 13y ago
Lua is weird mix between JavaScript and Python. I kind of like it.
znowi 13y ago
This is great! I wish every language had an intro like that :) It was interesting to find resemblance of Lua's classes to Perl's blessing. Always meant to look into the language and this tutorial made me do it. I also learned about the LÖVE game engine, which I'm going to play with this week. Thank you! http://love2d.org/ http://love2d.org/
- bananpermobil 13y ago
  If you're playing with love2d you might as well want to check out Zoetrope, I found it very awesome. http://libzoetrope.org/ http://libzoetrope.org/
  - tripzilch 13y ago
    This looks interesting, can you explain the difference between Zoetrope and LÖVE? The former seems to be built on top of the latter, yes? Are there particular things lacking in LÖVE that Zoetrope fills in? I couldn't find this info quickly on their sites.
    - LeonidasXIV 13y ago
      Looks like it has collision detection whereas for LÖVE you'd use Hardon Collider, has Tiled level loading whereas you'd need a plugin for LÖVE, etc. Basically, lots of stuff that you'd include in your games anyway. Looks nice and has better documentation than LÖVE. Thanks for posting it, I didn't know about it before.
deleted 13y ago
[deleted]
J_Darnley 13y ago
That page could do with a little syntax highlighting, at least for the comments. -- does not stand out.
- dag11 13y ago
  There is and has been syntax highlighting for me. Weird that you don't see it.
chii 13y ago
very comprehensive and interesting! i wish theres one for other languages too.
vishal0123 13y ago
Just awesome. I wonder whether this type of example-based snippet exist for other languages.
agscala 13y ago
I prefer learning this way also, so I wrote something sort of similar for Vimscript a while back. The # of people that ever need to use vimscript is low, but it's out there for people to get their feet wet. http://andrewscala.com/vimscript/ http://andrewscala.com/vimscript/
ErikRogneby 13y ago
Maybe for the next Ludnum Dare... nice write up comparison of lua based game engines: http://www.gamefromscratch.com/post/2012/09/21/Battle-of-the-Lua-Game-Engines-Corona-vs-Gideros-vs-Love-vs-Moai.aspx http://www.gamefromscratch.com/post/2012/09/21/Battle-of-the...

357 points by tylerneylon 13y ago

lukefreiler 13y ago

I love this. I'd like/pay to have a consistent library of exactly this for other languages.

digitalsushi 13y ago
A scripting language rosetta stone. Here's one http://www.lurklurk.org/rosetta.html http://www.lurklurk.org/rosetta.html
- lukefreiler 13y ago
  Yes, this - but with more languages and in the format of this topic. Just a really easy read.
makeset 13y ago
Who's up for the C++ version? :)

digitalsushi 13y ago

Thanks! Lua is used all over the place in wireshark user scripts. This is super useful.

programminggeek 13y ago

I would like to say that the easiest way for me to learn lua really fast was to build games with Corona using lua. Having a great tool that gives great feedback right away makes learning a language more fun IMO.

potomak 13y ago
Almost the same experience but with Love2D[1] instead of Corona. After learning Lua I also suggest to take a look at MoonScript[2] a dynamic scripting language that compiles into Lua, you can think about it as the CoffeeScript of Lua. [1] http://love2d.org/ http://love2d.org/ [2] http://moonscript.org/ http://moonscript.org/
- Tloewald 13y ago
  Codea (ios) is also nice. My first forays into Lua were hacking WoW UI components.
jamesbritt 13y ago
I got my feet wet with Lua by writing custom OSC handlers for Renoise. There were the expected "WTF?" moments but having something running and doing something practical is a great motivator.
seclorum 13y ago
Likewise! For me, it was MOAI: http://getmoai.com/ http://getmoai.com/ Since I became a Lua programmer, I really can't stand any other languages, and I've rapidly switched to it for my scripting needs. Tables are just soooo lovely. ;)

karpathy 13y ago

This is awesome. I will take [a single huge list of self-explanatory example snippets (with a few short comments here and there) for 95% of use cases] over [detailed walls-of-text docs pages spread across a hierarchy of topics] any day.

tylerneylon 13y ago
Thanks. My goal was to write the tutorial I wish I had when I started. Your description also matches my own preferred learning style.
- StavrosK 13y ago
  Were you inspired by http://www.stavros.io/tutorials/python/ http://www.stavros.io/tutorials/python/, by any chance?
- anoymous9352 13y ago
  Mine too. If I had found this back when I was learning Lua, I'm certain I'd have bookmarked it and referred to it regularly. I just hope beginners don't absorb the coding style too much >:)
uniclaude 13y ago
I'm glad this comment sits at the top of this thread. I do hope that more and more learning resources come to us in this form, which is a very good thing to give you an idea of wether you would like to jump into a language (or maybe even a framework/platform?). OP did a very good job. That said, Lua is quite the special case, as it does not require much time to get up and running with it. This is one of the reasons why it is the scripting language of Redis by the way (Antirez even wrote Total time require to master it enough? 5 minutes.[1] regarding building scripts for Redis). [1]:http://oldblog.antirez.com/post/scripting-branch-released.html http://oldblog.antirez.com/post/scripting-branch-released.ht...
kemist 13y ago
Can't agree with you more!
13y ago

piqufoh 13y ago

I love this - if every language could have something like this written up it would be amazing. It just about fits into my attention span!

chubot 13y ago
Well, it helps a lot that Lua is by design a very small language :) Python is actually much bigger nowadays -- I would challenge someone to come up with something this simple that doesn't leave out a lot of stuff you will encounter in real code. The extra features ("bloat") do matter. I like the idea of Lua a lot, but when I started programming in it, it unfortunately felt like a less capable Python to me.
- TillE 13y ago
  Lua and Javascript are quite similar in that way: nice little languages that fall apart really quickly when you try building anything reasonably large or complex. I don't really understand the attraction, except in certain niches like Lua as an embedded scripting engine, when you really need something that can be trivially sandboxed.
  - landhar 13y ago
    > [...] except in certain niches like Lua as an embedded scripting engine, when you really need something that can be trivially sandboxed. Isn't that exactly the reason JavaScript exists in the first place (i.e.: an embedded scripting engine for browsers) ?
- jnbiche 13y ago
  I'm sure you're aware of Penlight, which does a very nice job of providing a "batteries included" library similar to Python's for Lua.
  - untothebreach 13y ago
    I definitely wasn't, thanks for the tip!

outworlder 13y ago

This is awesome. On that note, I don't understand all the javascript craze. Lua has been around for quite some time, and it's small, with well-defined semantics, a nice set of features, the interpreter is small and very fast, you can get even faster with LuaJIT, etc. Browsers should have adopted that ages ago.

fhd2 13y ago
Yeah, I see Lua in many ways as "JavaScript done right". I also found it considerably easier to integrate than something like V8, and it appears to be easier to use for non-programmers. It definitely deserves to be more popular.
- taproot 13y ago
  Javascript being used by non programmers is 95% of the problems with javascript.. care to explain your problems with js and maybe expand on how lua is done right?
  - ufo 13y ago
    Lua is a much smaller language and overall it is much more consistent and has less corner cases than Javascript since the language had the opportunity to evolve over the years instead of needing to retain backwards compatibility with browsers from 1995. For example: * Lua has proper lexical scoping instead of the confusing "function scoping" of Javascript (so there is no need to use the IIFEs hack). * Lua has a Python-style lexicaly scoped self instead of the error prone dynamically scoped "this". No need to use `var taht = this` if you have nested functions. * The metatable system is much more flexible than the simple JS prototypal inheritance system (you can sort of implement "method missing" instead of being forced to only delegate to a concrete table. * You can use anything as a Lua table key. In JS all keys are converted to strigns. Lua also supports weak references. * Coroutines! Its sort of like ES6 generators and is super awesome. Async programming is infinitely more pleasant in Lua than it currently is in JS because you don't need to convert code to continuation passing style.
  - fhd2 13y ago

nathas 13y ago

That was lovely. I always had a hard time wrapping my head around the exact behavior of metatables when I messed with Lua a few years back. Thanks!

nbouscal 13y ago

Obligatory: Teach Yourself Programming in Ten Years — http://norvig.com/21-days.html http://norvig.com/21-days.html

dave1010uk 13y ago

Along the same lines is http://hyperpolyglot.org/ http://hyperpolyglot.org/ (which has been posted here a few times). This is useful both for learning a new language and for a quick reference for languages you're not so hot on. It's also very interesting to compare similarities and how languages have influenced each other. It seems (from the comments here and my own experience) that many people really like this style of learning. It would be great to see it applied in more areas.

adambard 13y ago
I find the inline-commented version a bit easier to read and to reason about, personally.
copx 13y ago
Thanks for reminding me of Io.. not. I was so happy with Lua and thought it was such an elegant and clean language.. then I looked at the side-by-side comparison between Lua and Io on the site you linked.. and now it seems clumsy and ugly. Unfortunately a language is only as good as its implementation and tooling and Io's implementation is "experimental" at best (and development is pretty much dead) + the utter lack of tools and third-party support so I will have to stick with Lua.. and try very hard to forget Io again.

Dylan16807 13y ago

This is a neat little reference but I can't waste the opportunity. I've seen people say they've never seen complaints about fonts being too big? Well here I am, complaining that the fonts are so big this page is hard for me to read without zooming out.

jeltz 13y ago

Having a font size of 25.33pt makes the website impossible to read without zooming out 3 steps. I would be happy if people stopped using tiny and huge default font sizes.

ricardobeat 13y ago
You can zoom in/out as much as you'd like, as you already know, so there is no need to force your personal taste on everyone else.
bananpermobil 13y ago
Well, it looks very good and reads very good on my ipad and on my tiny screen on my notebook. Otherwise I would've to zoom in, not a big deal though, do you think?

sharkbot 13y ago

I'm going to be "that guy": -- These are the same: -- ...snip... local function g(x) return math.sin(x) end local g = function (x) return math.sin(x) end According to the Lua Reference Manual [1], this example isn't correct. Rather, this is the correct translation: local function g(x) return math.sin(x) end local g; g = function (x) return math.sin(x) end From the manual: "This only makes a difference when the body of the function contains references to f." [1] http://www.lua.org/manual/5.2/manual.html#3.4.10 http://www.lua.org/manual/5.2/manual.html#3.4.10

anonymoushn 13y ago
What this means in practice: > local g=function() print(type(g)) end g() nil > local function g() print(type(g)) end g() function
tylerneylon 13y ago
You're right; I fixed that part.
- fab13n 13y ago
  you also miss a couple of "local newObj" in constructors.

hanjos 13y ago

Nice work! One nitpick: local function declarations, like local function g(x) return g(x) end are actually the same as writing local g; g = function (x) return g(x) end . Without that first local g; statement, local functions wouldn't be able to call themselves recursively.

tylerneylon 13y ago
yep; fixed

thyrsus 13y ago

First, that was very useful; bookmarked. That took me 30 minutes to read. I think I might feel like I've learned the language after spending 8 hours working the examples a la "Learn Python the Hard Way". Luckily, I'm not competing with the folks here that learned it within 15 minutes ;-).

tylerneylon 13y ago
The title is a bit optimistic :) That's how long it takes me to read as if I were reading a novel, which isn't quite fair. I wanted to express something like "hey, this guide is for programmers and is surprisingly short and easy to consume considering it covers the large majority of the language." The current title seemed a bit snazzier.

alecdbrooks 13y ago

A logical next step might be to do do the Lua Missions (read: koans): https://github.com/kikito/lua_missions https://github.com/kikito/lua_missions. (Disclaimer: The missions look good, but I haven't personally tried them.)

jballanc 13y ago
Actually, the Lua Missions are excellent! I highly recommend taking the time to work through them. More than just a series of exercises (like most of the foo-koans), there's actually a narrative and a larger lesson you can learn if you work through the full problem set.
- otikik 13y ago
  Hi, Lua Missions author here! Thanks for the kind words. One word of warning though: I never got around to make one mission about coroutines. But I accept pull requests :)

daenz 13y ago

Lua can be great. I've worked with it extensively on a personal project, where I've embedded it in a C++ app. However, there are some things that you will hate: * Trying to correctly do "inheritance" * Having to write all of your batteries for common ops * Array indices begin at 1! * Poor debugging support Aside from those thing, Lua is great. It's crazy fast and easy to embed.

noonespecial 13y ago

I learned to love lua when writing basic sysadmin scripts for OpenWRT based systems. I had previously used perl for sysadmin stuff, but perl (even microperl) took too much space on OpenWRT boxes with 4MB flash drives. Lua to the rescue. Now I chafe when I have to go pack to perl. I do wish someone had handed me this on the first day I realized I needed lua.

landhar 13y ago

This is very cool, the only way I can see this could be improved upon is by adding unit tests somehow (so that you can catch behavior changes when upgrading to a newer version of lua).

spc476 13y ago
I'm not sure it's really necessary---Lua 5.0 came out in 2003, 5.1 in 2006 and 5.2 in late 2011. It doesn't change that fast.

silentbicycle 13y ago

This is a good start, but there's also some deeper ideas in Lua. It has a good implementation of coroutines, for example; if you're familiar with continuations from Scheme, they fit most of the same uses. (They're like generators from Python or fibers from Ruby, but with less edge cases.) The C interop is also a Big Deal. Lua seems like a cute little language, like a cleaner Javascript, but it's a LOT more useful if you're also proficient in C. Also, Lua will run anywhere you have an ANSI C compiler and a modest amount of space.

chalst 13y ago
Coroutines are tricky, and you need to explain them, not just present a bit of code. I think it is the right decision to omit them from a 15-minute intro. The C API is way out of scope. I would cover assert() statements and the common (exit_status, result) var return, since that is so idiomatic. Maybe also loading chunks.
- silentbicycle 13y ago
  I agree, they're tricky. I'm currently working on a blog post about them. :)

ufo 13y ago

This would look much better with syntax highlighting.

spacecowboy 13y ago

That was a pretty cool crash course on Lua Tyler! Thanks for putting that together and sharing it. After having had worked with numerous languages over the years such as Fortran, Pascal, Ada, C, Java, C++, C#, Python and Objective-C, I must say that working with Lua is my favorite. I'm thankful to a buddy of mine for introducing it to me. My own personal experience has shown me that working with Lua really allows you to focus on solving the problem versus getting wrapped around the axle at the programming language level. Thanks again

mneary 13y ago

Anyone else catch the Gauss reference[1] in the for loop section? [1] http://en.wikipedia.org/wiki/Carl_Friedrich_Gauss#Anecdotes http://en.wikipedia.org/wiki/Carl_Friedrich_Gauss#Anecdotes

makeset 13y ago
Ha! I got karl, was wondering who fred was.
tylerneylon 13y ago
You have a keen eye for subtle references! I didn't expect many people to get that one :) There's another math anecdote reference hidden in there as well - probably even more obscure than Karl's sum.
- tekacs 13y ago
  Upon reading this comment had to skim the whole thing looking for more (hadn't yet finished reading). No more maths references than tau found yet. :/
  - tylerneylon 13y ago
    Ramanujan and Hardy are two well-known mathematicians who collaborated in Britain between 1914 and 1920. One day Hardy took taxi number 1729 to visit Ramanujan, and remarked to him that he (Hardy) could think of nothing special about the number (1729). Ramanujan replied that it was in fact the first number expressible as the sum of two cubes in two different ways (1^3 + 12^3 = 9^3 + 10^3). The story has since become an anecdotal symbol of Ramanujan's brilliant mind. http://en.wikipedia.org/wiki/1729_(number) http://en.wikipedia.org/wiki/1729_(number) That's a very obscure reference, though, so I apologize for sending anyone looking based on my previous comment.
    - tekacs 13y ago
      Haha I'd heard this anecdote before, so it's my own fault for missing it. :) Thanks for the great article and indeed fun references!

dakimov 13y ago

Great sheet. -- Variables are global by default. thisIsGlobal = 5 -- Camel case is common. -- Undefined variables return nil. -- This is not an error: foo = anUnknownVariable -- Now foo = nil. -- Only nil and false are falsy; 0 and '' are true! Didn't read further. Bad language design. Must die.

otikik 13y ago
First two can be changed quite easily: http://metalua.luaforge.net/src/lib/strict.lua.html http://metalua.luaforge.net/src/lib/strict.lua.html The last one is awesome.
seclorum 13y ago
Bah! Why is it bad and why must it die? Please add content to this discussion - I don't agree with you, but maybe you can convince me. Try it.
anonymoushn 13y ago
Could you tell us anything about why these things are bad? Regarding the last point (the one that you cannot change), I'm not sure I prefer the behavior of any other language. In Python, for instance, all of the number-like things I tried were falsy iff they were 0, and I found that almost any container is falsy iff it is empty, but Queues are always truthy. This is a weird exception, and I would rather not have to remember it. Collections and numeric types defined in external libraries can easily have the same problem.
- dakimov 13y ago
  Global automatically declared variables is a well-known bad feature of some non-modern languages that gives nothing but an opportunity to make hardly detectable mistakes because of misprints. Arbitrary nonsensical type casts must be prohibited. The compiler/interpreter/IDE must infer types and help the programmer to catch their mistakes as early as possible. As a general rule of language design, if something looks unintentional or ambiguous to a human, it should look so to a compiler/interpreter. The more coherent the programming environment is to your conscience, the easier the programming is.

johnchristopher 13y ago

Bonus point for Cloud Atlas reference :)

deleted 13y ago

[deleted]

daGrevis 13y ago

Lua is weird mix between JavaScript and Python. I kind of like it.

znowi 13y ago

This is great! I wish every language had an intro like that :) It was interesting to find resemblance of Lua's classes to Perl's blessing. Always meant to look into the language and this tutorial made me do it. I also learned about the LÖVE game engine, which I'm going to play with this week. Thank you! http://love2d.org/ http://love2d.org/

bananpermobil 13y ago
If you're playing with love2d you might as well want to check out Zoetrope, I found it very awesome. http://libzoetrope.org/ http://libzoetrope.org/
- tripzilch 13y ago
  This looks interesting, can you explain the difference between Zoetrope and LÖVE? The former seems to be built on top of the latter, yes? Are there particular things lacking in LÖVE that Zoetrope fills in? I couldn't find this info quickly on their sites.
  - LeonidasXIV 13y ago
    Looks like it has collision detection whereas for LÖVE you'd use Hardon Collider, has Tiled level loading whereas you'd need a plugin for LÖVE, etc. Basically, lots of stuff that you'd include in your games anyway. Looks nice and has better documentation than LÖVE. Thanks for posting it, I didn't know about it before.

deleted 13y ago

[deleted]

J_Darnley 13y ago

That page could do with a little syntax highlighting, at least for the comments. -- does not stand out.

dag11 13y ago
There is and has been syntax highlighting for me. Weird that you don't see it.

chii 13y ago

very comprehensive and interesting! i wish theres one for other languages too.

vishal0123 13y ago

Just awesome. I wonder whether this type of example-based snippet exist for other languages.

agscala 13y ago

I prefer learning this way also, so I wrote something sort of similar for Vimscript a while back. The # of people that ever need to use vimscript is low, but it's out there for people to get their feet wet. http://andrewscala.com/vimscript/ http://andrewscala.com/vimscript/

ErikRogneby 13y ago

Maybe for the next Ludnum Dare... nice write up comparison of lua based game engines: http://www.gamefromscratch.com/post/2012/09/21/Battle-of-the-Lua-Game-Engines-Corona-vs-Gideros-vs-Love-vs-Moai.aspx http://www.gamefromscratch.com/post/2012/09/21/Battle-of-the...