Deref look-char
Remove error

Functions that need that functionality can just throw Exceptions on
their own.
Change a letter to lowercase
Remove look-char and get-char

I'm just going to have functions work on passed-in and operate this from
the REPL for now.
Have match return a boolean
Make is-alpha? simpler
Don't throw Exceptions yet
Refactor get-name away from get-char
Remove print* calls from emit and emitln
Fix get-name's reliance on the old look-char
Add get-num
Add a \newline to the end of emitln
Have expected throw an exception again
Fix the if test expressions
Add expression
Have is-digit? and is-alpha? str input