In most programming languages there is a sharp distinction between program and data. Data are the things you can manipulate in your program, things like numbers and letters. These things live in variables, which can be given new values by your program. In Logo the distinction is not so sharp. In this chapter we'll use a pair of more advanced tools that allow a program to create more program.
Text is an operation that takes one input, a word.
That word must be the name of a user-defined procedure. The output from text is a list. The first member of that list is a list containing the names of the inputs to the chosen procedure. The remaining members of the output list are instruction lists, one for each line in the definition of the procedure. Berkeley Logo allows user-defined procedures with optional inputs.