A token is a string containing no white space characters (space, tab, newline).
A scanner allows programmers to extract and examine tokens from a source string one at a time.
The source string can be internal to the program or it can be from a file.
If a token represents a number or boolean, a scanner can convert it to the number or boolean that it represents.
See parse.java
A console is a simple loop that repeatedly:
1. prints a prompt
2. reads a command
3. quits if the command is the "quit" command
4. executes the command
5. displays the result
See Console.java