Bad things about your favourite programming language

Lua's not a programming language

I guess the main "issue" is that it's designed as an extension language so it's really not suitable for large standalone projects, for similar reasons Fiel mentioned about Python. Then again I don't do large standalone projects in the first place, or really anything used by other people, so it's all good for me.

Also it's very minimalistic in terms of syntactical constructs and standard libraries, so you don't have classes, bit ops, regex, etc and so for pretty much anything beyond basics (math, string, list, I/O, system) you need to find and install a third-party module, if one exists.

And due to string immortality there are stupid things it lets you do, like this

Code:

s = ''
for i = 1, 100000 do
    s = s .. 'a'      -- string concatenate
end

which takes 33 seconds to complete on my machine because it makes a copy of the string each iteration and collects garbage every few times.

C# and Java have StringBuilder classes that allow you to build up a string like in that loop without incurring the cost of creating a new string object with each concatenation. Maybe Lua has something like that?