Source code for the programs you include should go in this directory
(and subdirectories of this directory). You include this code into
your document using

  <code file="code/path.rb" />

The intent is to make all of this code runnable (and hence
testable). However, sometimes this means putting more stuff int
hesource files than you'd like to include int he book. To deal with
this, you tell the <code> processor only to include certain chunks of
your source in the book. You identify these chunks using comments
containing "START:name" and "END:name". When you do

 <code file="code/path.rb" part="name" />

then only the code bracketed by these comments will be included.

Say you were writing a Ruby program to parse lines out of
/etc/passwd. You might code the program as:

  passwd.rb:

     #START:openclose
     f = File.open("/etc/passwd")
     # ...
     #END:openclose

     #START:parse
     while line = f.gets
       puts line if line =~ dave
     end
     #END:parse

     #START:openclose
     f.close 
     #END:openclose

In your book, you could then write.

  Before processing the file, we have to open it. After finishing,
  it's polite to close it.

  <code file="code/passwd.rb" part="openclose" />

  But what to be do with the open file? In this case, we'll read
  through it and print any lines containing
  <stringinfile>dave</stringinfile>.

  <code file="code/passwd.rb" part="parse" />

Notice how you can have multiple START/ENDs with the same name.


You might want to subdivide this directory into subdirectories per
project or chapter or whatever.
