Here we use the stuff defined in the AST and Parsec modules to parse things.
|:: [(String, String)]|
list of alises to expand
|-> Either (String, Bool) [Command]|
This is the main export here. We take a list of aliases for the
environment and a
String to parse. The return type is
[Command] if parsing succeeded and
Left (String,Bool) upon
True when the error was fatal/unrecoverable.