day 1: fix formatting a lil and add comments

01/main.lua

@@ -1,5 +1,6 @@
 input = {};
 
+-- import input from external file
 for line in io.lines("./input.txt") do
   table.insert(input, line)
 end
@@ -7,22 +8,28 @@ end
 parsed = {};
 
 for key, value in pairs(input) do
+  -- strip non-numerical chars from input
   local alphastrip = string.gsub(value, "[%a]", "");
 
+  -- if remaining number is 1 char long, double it and then put it into the table
   if string.len(alphastrip) == 1 then
     local doubled = alphastrip .. alphastrip;
     table.insert(parsed, doubled);
+
+  -- if remaining number is 2 chars long, put it into the table as-is
   elseif string.len(alphastrip) == 2 then
     table.insert(parsed, alphastrip);
+
+  -- otherwise fetch first and last digits, concat them, and insert them into the table that way
   else
     local digitstrip = string.match(alphastrip, "%d", 1) .. string.match(alphastrip, "%d", -1);
     table.insert(parsed, digitstrip);
-    --print(digitstrip);
   end
 end
 
 result = 0;
 
+-- add all the values stored in `parsed` together
 for key, value in pairs(parsed) do
   result = value + result;
 end