Regular Expressions

For assignment 2 we have been tasked with working on regular expressions, and regular expression trees. Since I hadn't really heard anything about regular expressions I decided to do some Googling before I began. Turns out, regular expressions are quite useful. They allow for matching a variety of strings by simply using the correct expression. There are different types and different languages that use regular expressions but they are generally used in similar ways. They can be extremely useful for pattern matching; for something simple like looking for whitespace or even full sentences.

I spent some time struggling with the first function that I was working on: is_regex() – which determines whether or not a string is a valid regular expression. It is of course a recursive function and really doesn't seem that difficult at first glance, but there are some cases to consider which take a bit more work. The challenge is basically to determine the proper amount of nesting for parentheses inside a string. I tried a couple methods which worked on some test cases but not all of them. I ended up using a helper function to get what I needed done and it seemed like a pretty clear solution so I'm happy with that.

I'm not very far into the rest of the assignment so I better get to that and update about that next week!