A partial function that will take the String value of the passed argument,
and convert it to type A.
A partial function that will take the String value of the passed argument,
and convert it to type A.
Typical usage might be for parsing String to Int/Float/Custom Domain, e.g.
for a Argument[Int], parse = str => str.toInt.
Advanced usage could be used to do more targeted work as well, such as
processing the argument directly, versus simply obtaining the value for it
to be parsed later, e.g. for a Argument[String], parse = str =>
str.toUpperCase