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Pollen:   the book is a program

Pollen: the book is a program

Matthew Butterick <mb@mbtype.com>

 #lang pollen package: pollen

Pollen is a publishing system that helps authors create beautiful and functional web-based books. Pollen includes tools for writing, designing, programming, testing, and publishing.

I used Pollen to create my book Butterick’s Practical Typography. Sure, go take a look. Is it better than the last digital book you encountered? Yes it is. Would you like your book to look like that? If so, keep reading.

At the core of Pollen is an argument:
  • First, that digital books should be the best books we’ve ever had. So far, they’re not even close.

  • Second, that because digital books are software, an author shouldn’t think of a book as merely data. The book is a program.

  • Third, that the way we make digital books better than their predecessors is by exploiting this programmability.

That’s what Pollen is for.

Not that you need to be a programmer to use Pollen. On the contrary, the Pollen language is markup-based, so you can write & edit text naturally. But when you want to automate repetitive tasks, add cross-references, or pull in data from other sources, you can access a full programming language from within the text.

That language is Racket. I chose Racket because while the idea for Pollen had been with me for several years, it simply wasn’t possible to build it with other languages. So if it’s unfamiliar to you, don’t panic. It was unfamiliar to me. Once you see what you can do with Pollen & Racket, you may be persuaded. I was.

Or, if you can find a better digital-publishing tool, use that. But I’m never going back to the way I used to work.

    1 Installation

    2 Quick tour

      2.1 Creating a source file

      2.2 Running a source file

      2.3 Naming, saving, and rendering a source file

      2.4 The project server

      2.5 Intermission

      2.6 Pollen as a preprocessor

      2.7 Markdown mode

      2.8 Markup mode

      2.9 Templates

      2.10 PS for Scribble users

      2.11 The end of the beginning

    3 Backstory

      3.1 Web development and its discontents

      3.2 The better idea: a programming model

      3.3 “Now you have two problems”

      3.4 Rethinking the solution for digital books

      3.5 Enter Racket

      3.6 What is Pollen?

      3.7 Further reading

    4 The big picture

      4.1 The book is a program

      4.2 One language, multiple dialects

      4.3 Development environment

      4.4 A special data structure for HTML

      4.5 Pollen command syntax

      4.6 The preprocessor

      4.7 Templated source files

      4.8 Pagetrees

    5 First tutorial

      5.1 Prerequisites

      5.2 The relationship of Racket & Pollen

      5.3 Starting a new file in DrRacket

        5.3.1 Setting the #lang line

        5.3.2 Putting in the text of the poem

        5.3.3 Saving & naming your source file

      5.4 Using the project server

        5.4.1 Starting the project server with raco pollen

        5.4.2 Using the dashboard

        5.4.3 Source files in the dashboard

      5.5 Working with the preprocessor

        5.5.1 Setting up a preprocessor source file

        5.5.2 Creating valid HTML output

        5.5.3 Adding commands

        5.5.4 Racket basics (if you’re not familiar)

        5.5.5 Defining variables with commands

        5.5.6 Inserting values from variables

        5.5.7 Inserting variables within CSS

      5.6 First tutorial complete

    6 Second tutorial

      6.1 Prerequisites

      6.2 Prelude: my principled objection to Markdown

      6.3 Markdown in Pollen: two options

        6.3.1 Using Markdown with the preprocessor

        6.3.2 Authoring mode

        6.3.3 X-expressions

        6.3.4 Markdown authoring mode

      6.4 Templates

        6.4.1 The ->html function and the doc variable

        6.4.2 Making a custom template

        6.4.3 Inserting specific source data into templates

        6.4.4 Linking to an external CSS file

      6.5 Intermission

      6.6 Pagetrees

        6.6.1 Pagetree navigation

        6.6.2 Using the automatic pagetree

        6.6.3 Adding navigation links to the template with here

        6.6.4 Handling navigation boundaries with conditionals

        6.6.5 Making a pagetree source file

        6.6.6 index.ptree & the project server

      6.7 Second tutorial complete

    7 Third tutorial

      7.1 Prerequisites

      7.2 Pollen markup vs. XML

        7.2.1 The XML problem

        7.2.2 What Pollen markup does differently

        7.2.3 “But I really need XML…”

      7.3 Writing with Pollen markup

        7.3.1 Creating a Pollen markup file

        7.3.2 Tags & tag functions

        7.3.3 Attributes

        7.3.4 What are custom tags good for?

        7.3.5 Semantic markup

        7.3.6 Format independence

        7.3.7 Using custom tags

        7.3.8 Choosing custom tags

      7.4 Tags are functions

        7.4.1 Attaching behavior to tags

        7.4.2 Notes for experienced programmers

 Point of no return

 Multiple input values & rest arguments

 Returning an X-expression

 Interpolating variables into strings

 Parsing attributes

      7.5 Intermission

      7.6 Organizing functions

        7.6.1 Using Racket’s function libraries

        7.6.2 Using the directory-require.rkt file

      7.7 Decoding markup via the root tag

      7.8 Putting it all together

        7.8.1 The directory-require.rkt file

        7.8.2 The template

        7.8.3 The pagetree

        7.8.4 A CSS stylesheet using the preprocessor

        7.8.5 The content source files using Pollen markup

        7.8.6 The result

      7.9 Third tutorial complete

    8 Using raco pollen

      8.1 Making sure raco pollen works

      8.2 raco pollen

      8.3 raco pollen help

      8.4 raco pollen start

      8.5 raco pollen render

      8.6 raco pollen clone

    9 File formats

      9.1 Source formats

        9.1.1 Command syntax using ◊

        9.1.2 Any command is valid

        9.1.3 Standard exports

        9.1.4 Custom exports

        9.1.5 The directory-require.rkt file

        9.1.6 Preprocessor (.pp extension)

        9.1.7 Markdown (.pmd extension)

        9.1.8 Markup (.pm extension)

        9.1.9 Pagetree (.ptree extension)

      9.2 Utility formats

        9.2.1 Scribble (.scrbl extension)

        9.2.2 Null (.p extension)

    10 ◊ command overview

      10.1 The golden rule

      10.2 The lozenge glyph (◊)

      10.3 The two command modes: text mode & Racket mode

        10.3.1 The command name

 Invoking tag functions

 Invoking other functions

 Inserting the value of a variable

 Inserting metas

 Inserting a comment

        10.3.2 The Racket arguments

        10.3.3 The text argument

      10.4 Further reading

    11 Module reference

      11.1 Cache

      11.2 Decode

        11.2.1 Block

        11.2.2 Typography

      11.3 File

      11.4 Pagetree

        11.4.1 Making pagetrees with a source file

        11.4.2 Making pagetrees by hand

        11.4.3 Using pagetrees for navigation

        11.4.4 Using index.ptree in the dashboard

        11.4.5 Using pagetrees with raco pollen render

        11.4.6 Functions

 Predicates & validation



      11.5 Render

      11.6 Template

      11.7 Tag

      11.8 Top

      11.9 World

    12 Acknowledgments

    13 License & source code