Wiley-World.of.Warcraft.Programming.A.Guide.and.Reference.for.Creating.WoW.Addons

92 Part I ■ Learning to ProgramIn this example, the function foo() takes two arguments (arg1 and arg2)and returns a single value someReturn. These signatures can also indicateoptional arguments, by enclosing them in square brackets:somereturn = foo(arg1 [, arg2])This notation indicates that the second argument to foo() is optional. Whenyou see this, you should consult the description of the function and argumentsto determine the behavior of the function because it varies.Table LibraryThe table library provides several functions that allow you to easily addelements, remove elements, and sort array tables. In addition, a utility functionis provided that works outside of the array part of the table, returning themaximum numeric index used in the table. The former functions all operateexclusively on the array part of the table, whereas the latter can be used onany type of table.str = table.concat (table [, sep [, i [, j]]])The table.concat() function concatenates all entries of the array part ofa table, with an optional separator string sep. Given an array where allelements are strings or numbers, it returns table[i]..sep..table[i+1] ...sep..table[j]. The default value for sep is the empty string, the default fori is 1, and the default for j is the length of the table. If i is greater than j, itreturns the empty string.> tbl = {“alpha“, “beta“, “gamma“}> print(table.concat(tbl, “:“))alpha:beta:gamma> print(table.concat(tbl, nil, 1, 2))alphabeta> print(table.concat(tbl, “\n“, 2, 3))betagammaThis function is an easy way to print the elements of the array part of atable. As you can see, sep can be any string (including the newline character)because it’s just concatenated with the entries in the table.table.insert (table, [pos,] value)The table.insert() function inserts a new element into the array, optionallyat position pos, shifting other elements up to make space, if necessary. Thedefault value for pos is n+1, where n is the length of the table. Therefore, a callof table.insert(t,x) inserts x at the end of table t.