I hate having to install libraries (especially those that want me to use installer packages to install them). If you’re looking for a clean solution for a directory listing on an absolute path in Lua, look no further. Building on the answer that sylvanaar provided, I created a function that returns an array of all … Read more
Here is an implementation of a locals() function. It will return a table of locals from the calling scope: function locals() local variables = {} local idx = 1 while true do local ln, lv = debug.getlocal(2, idx) if ln ~= nil then variables[ln] = lv else break end idx = 1 + idx end … Read more
the general case of iterating over an array and removing random items from the middle while continuing to iterate If you’re iterating front-to-back, when you remove element N, the next element in your iteration (N+1) gets shifted down into that position. If you increment your iteration variable (as ipairs does), you’ll skip that element. There … Read more
You already have the solution in the question — the only way is to iterate the whole table with pairs(..). function tablelength(T) local count = 0 for _ in pairs(T) do count = count + 1 end return count end Also, notice that the “#” operator’s definition is a bit more complicated than that. Let … Read more
About tables in general (oh, can’t you just give me an array) In Lua, a table is the single general-purpose data structure. Table keys can be of any type, like number, string, boolean. Only nil keys aren’t allowed. Whether tables can or can’t contain nil values is a surprisingly difficult question which I tried to … Read more
Table copy has many potential definitions. It depends on whether you want simple or deep copy, whether you want to copy, share or ignore metatables, etc. There is no single implementation that could satisfy everybody. One approach is to simply create a new table and duplicate all key/value pairs: function table.shallow_copy(t) local t2 = {} … Read more
You can set the function environment that you run the untrusted code in via setfenv(). Here’s an outline: local env = {ipairs} setfenv(user_script, env) pcall(user_script) The user_script function can only access what is in its environment. So you can then explicitly add in the functions that you want the untrusted code to have access to … Read more