Added comments

main.go

@@ -24,16 +24,21 @@ func priority(op rune) int {
 }
 
 /*
-	shuntingYard applies the Shunting-Yard algorithm
-
-to convert the given infix expression to postfix. This makes
-it easier to parse the algorithm when doing Thompson.
+The Shunting-Yard algorithm is used to convert the given infix (regeular) expression to postfix.
+The primary benefit of this is getting rid of parentheses.
+It also inserts explicit concatenation operators to make parsing easier in Thompson's algorithm.
 See: https://blog.cernera.me/converting-regular-expressions-to-postfix-notation-with-the-shunting-yard-algorithm/
 */
 func shuntingYard(re string) string {
 	re_postfix := make([]rune, 0)
-	re_runes := []rune(re)
-	/* Add concatenation operators */
+	re_runes := []rune(re) // Convert the string to a slice of runes to allow iteration through it
+	/* 	Add concatenation operators.
+	Only add a concatenation operator between two characters if both the following conditions are met:
+		1. 	The first character isn't an opening parantheses or alteration operator.
+			a. This makes sense, because these operators can't be _concatenated_ with anything else.
+		2. The second character isn't a 'closing operator' - one that applies to something before it
+			a. Again, these operators can'be concatenated _to_. They can, however, be concatenated _from_.
+	*/
 	for i := 0; i < len(re_runes); i++ {
 		re_postfix = append(re_postfix, re_runes[i])
 		if re_runes[i] != '(' && re_runes[i] != '|' {
@@ -45,8 +50,6 @@ func shuntingYard(re string) string {
 		}
 	}
 
-	// fmt.Println(string(re_postfix))
-
 	opStack := make([]rune, 0)  // Operator stack
 	outQueue := make([]rune, 0) // Output queue