Études for Erlang

Étude 5-2: Using the re Module

Write a module named dates that contains a function date_parts/1, which takes a string in ISO date format ("yyyy-mm-dd") and returns a list of integers in the form [yyyy, mm, dd]. This function does not need to do any error checking.

You’ll use the re:split/3 function from Erlang’s regular expression (re) module to accomplish the task. How, you may ask, does that function work? Ask Erlang! The command erl -man re will give you the online documentation for the re module.

Scroll down the resulting page until you find split(Subject, RE, Options) → SplitList and read the examples.

When you write the -spec for this function (you have been writing documentation for your functions, haven’t you?), the type you will use for the parameter is string().

Note

You can see a complete list of the built-in types at http://www.erlang.org/doc/reference_manual/typespec.html

Yes, I know this étude seems pointless, but trust me: I’m going somewhere with this. Stay tuned.

See a suggested solution in Appendix A.