11  Core Scheme is Not Enough

No useful program is an island; users want to use it even if they don't know Scheme. Generally users don't understand how to launch a Scheme function (or a function in any other language). They just want to launch an application. If they launch an application, they also want to enter data in a convenient way; they certainly don't want to learn how to create lists with cons and similar things like that. What we have learned so far, however, doesn't help us with either of the two problems. All we know is how to write Scheme functions and test them with small data samples. It is time to learn enough so that we can create full-fledged applications. We propose that you first take a look at part III, which discusses basic forms of input and output, and then part part:standalone, which presents the basic mechanisms for creating stand-alone executables


- check sections on S-expressions and blocks

- introduce "abstraction" design recipe on the fly with drawing/erasing ufos

- check all UFO code for compatibility with the running code.