Ok here is how the structure works:

main.ptx includes each of the chapter files ch-NAME.ptx, and each of the chapter files includes each of the section files sec-NAME.ptx.

The section files do a bunch of component= versioning. There are four components:

• "web": things that should only apply in the online version, not in either pdf
• "not-web": things that should only apply in pdf
• "workbook": things that should only appear in the workbook
• "not-workbook": things that should appear in both the fullprint and the online version

Here is how those components are used:

• two versions of the <title> tag generate either the plain title (not-workbook) or the title decorated with "- Practice exercises" (workbook)
• the text of the section is enclosed in an <introduction component="not-workbook">
• each of the "Do you know..." lists is in a separate document as an <ol> element
• a <conclusion component="workbook"> loads the "Do you know..." list in after the exercises in the workbook version
• a <conclusion component="not-workbook"> loads the "Do you know..." list in before the exercises in other versions
• The file NotSure.ptx prints some "not-sure" instructions in not-workbook formats and the "Don't forget!" alert in the workbook version
• WYD.ptx is a <conclusion component="workbook"> that is loaded between the exercises and the "Do you know ..." list

Some other important versioning happens in the exercise files ex-NAME.ptx:

• ex-intro.ptx is an <introduction> element that doesn't display in the workbook
• exercises 1-4 are not componented, so they appear in all builds
• if exercises 1-4 include xrefs to exercises 5-? in other sections, those "story also appears in" sentences are versioned in <em component="..."> tags
  • I reference the containing section rather than the exercise directly in the workbook component tag
• exercises 5-8 are written in <exercise component="not-workbook">

Custom xsl in the xsl folder is very important to how this book works. In the latex versions:

• Most importantly, it makes <exercises> respect <page> and @workspace in the workbook version
• it contains some header customization
• it contains some customization of the enumerate labels and makes nested enumerates with empty introductions behave similarly to vanilla latex
• it makes sections start with a pagebreak
• it kills some extra periods generated in titles
• it formats <aside> to appear as margin notes