Why Lua?

Post by ktr » Wed, Feb 01, 2012, 1:30 PM UTC

hythloday wrote: post #126

ktr wrote: post #74

Earlier quoted context omitted.

Sorry, I would actually consider myself quite proficient in Python. What I was trying to [unsuccessfully] show was that the underlying mechanics of Python's import mechanism are different then, say, Python's dict or list implementations. Whereas in Lua everything really is just a table. I ran into this (in Python) when I was trying to dynamically import code based on command line arguments and access the functions in…

Hey, thanks for the reply, I do see your point now--I thought you were referring to the usual case of importing modules. It's true that Python modules aren't implemented in terms of dicts or lists and that Python is a larger language than Lua, so I think I completely agree with the point you were making. :) For future reference, I'd implement your dynamic module importer like this: def dynamic_import(name): import im…

Post by Angostura » Wed, Feb 01, 2012, 2:57 PM UTC

Post by sshumaker » Wed, Feb 01, 2012, 4:15 PM UTC

cmf028 wrote: post #93

sshumaker wrote: post #53

Earlier quoted context omitted.

Not sure if I'd agree that Guile's FFI bindings are better than LuaJIT's FFI. It's certainly easier to declare a function in LuaJIT - you can take the definition directly from the header file, rather than transcoding it into s-exps. Compare: (define memcpy (let ((this (dynamic-link))) (pointer->procedure '* (dynamic-func "memcpy" this) (list '* '* size_t)))) vs. ffi.cdef [[ void * memcpy ( void * destination, const v…

"As for the speed, there's no reason that a lot of dynamic languages couldn't be as fast as LuaJIT. But none of them are even close. I wish LuaJIT was still up in the computer language shootout. The LuaJIT interpreter (with JIT turned off) is 3x faster than V8 on the PC, and faster than Java on Android. And that's the interpreter - the JITed code is way faster." [Citation Needed] I know of old benchmarks (pre Cranksh…

Post by jballanc » Wed, Feb 01, 2012, 5:23 PM UTC

zeen wrote: post #127

jballanc wrote: post #37

Earlier quoted context omitted.

To nitpick your nitpick: in Lua tables are the only composite data structure. Everything you listed is either atomic or opaque (you can hide composite datatypes in userdata, but you can't introspect the values). If you think about it, this is very similar to C where the only composite datatype is a struct (arrays are just sugar on pointer arithmetic). In fact, I think if you wanted to make a scriptable dialect of C,…

Well, since we are nitpicking nitpicks, allow me to nitpick your nitpick of a nitpick: Lua closures are also composite data structures. You can get/set their upvalues via the debug API. Behold: function create() local a,b,c,d,e,f,g,h,i,j; return function() print(a,b,c,d,e,f,g,h,i,j); end end function array_get(f, index) local k,v = debug.getupvalue(f, index); return v; end function array_set(f, index, value) debug.se…

Post by anghyflawn » Wed, Feb 01, 2012, 8:06 PM UTC

extension wrote: post #132

chubot wrote: post #6

Why isn't Lua more widely used? One reason is a consequence of it being an embedded language. Lua has had 5 major versions which are very incompatible with each other. You're just supposed to stick with the previous version until you upgrade your code. I read all the Lua papers, and they are quite fond of "getting it right" (which is refreshing). They will break things to get it right, whereas other languages stick w…

Not only does it lack a standard library, it lacks a standard metaobject protocol. The fact that a MOP can be implemented in Lua is very nifty, but not having a standard one makes an ecosystem of shared code very difficult.