Variables are used to assign values in Marigold. Unlike other languages,
variables in marigold do not store data. They act more like a nickname.
So if you use ask to get user value, set it as a variable, and use it
twice, it will ask the user twice. This is by design. Marigold is meant
to be as faithful to lambda calculus as possible. This means to have to be creative
and use lambda calculus patterns in your code.
Every variable is immutable. This means that there are no in-place operations. However, you
can make something similar by using ->.
[variable name] = [variable value];