From a93405f5a52c04224164e2f34b24aed8231a7ec7 Mon Sep 17 00:00:00 2001 From: Matthew Butterick Date: Sun, 7 Sep 2014 19:43:26 -0700 Subject: [PATCH] improve pagetree docs (closes #16) --- doc/Module_reference.html | 2 +- doc/Pagetree.html | 2 +- doc/doc-index.html | 2 +- doc/index.html | 2 +- scribblings/pagetree.scrbl | 129 +++++++++++++++++++++++++++++++++++-- 5 files changed, 127 insertions(+), 10 deletions(-) diff --git a/doc/Module_reference.html b/doc/Module_reference.html index fa0e418..d72c3c2 100644 --- a/doc/Module_reference.html +++ b/doc/Module_reference.html @@ -1,2 +1,2 @@ -11 Module reference
►Pollen:   the book is a program
▼11 Module reference
11.1 Cache
11.2 Decode
11.3 File
11.4 Pagetree
11.5 Render
11.6 Template
11.7 Tag
11.8 Top
11.9 World
6.1.0.5
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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 Navigation

      11.4.2 Utilities

    11.5 Render

    11.6 Template

    11.7 Tag

    11.8 Top

    11.9 World

    ← prev  up  next → 
 
\ No newline at end of file +11 Module reference
►Pollen:   the book is a program
▼11 Module reference
11.1 Cache
11.2 Decode
11.3 File
11.4 Pagetree
11.5 Render
11.6 Template
11.7 Tag
11.8 Top
11.9 World
6.1.0.5
    ← prev  up  next → 

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

        11.4.6.1 Predicates & validation

        11.4.6.2 Navigation

        11.4.6.3 Utilities

    11.5 Render

    11.6 Template

    11.7 Tag

    11.8 Top

    11.9 World

    ← prev  up  next → 
 
\ No newline at end of file diff --git a/doc/Pagetree.html b/doc/Pagetree.html index 53239ea..fe93780 100644 --- a/doc/Pagetree.html +++ b/doc/Pagetree.html @@ -1,2 +1,2 @@ -11.4 Pagetree
►Pollen:   the book is a program
▼11 Module reference
11.1 Cache
11.2 Decode
11.3 File
11.4 Pagetree
11.5 Render
11.6 Template
11.7 Tag
11.8 Top
11.9 World
►11.4 Pagetree
On this page:
pagetree?
validate-pagetree
pagenode?
pagenodeish?
->pagenode
11.4.1 Navigation
current-pagetree
parent
children
siblings
previous
previous*
next
next*
11.4.2 Utilities
pagetree->list
in-pagetree?
path->pagenode
6.1.0.5
    ← prev  up  next → 

11.4 Pagetree

 (require pollen/pagetree) package: pollen

A pagetree is a hierarchical list of Pollen output files. A pagetree source file has the extension .ptree. A pagetree provides a convenient way of separating the structure of the pages from the page sources, and navigating around this structure.

Pagetrees are made of pagenodes. Usually these pagenodes will be names of output files in your project. (If you think it would’ve been more logical to just call them “pages,” perhaps. When I think of a web page, I think of a file on a disk. Whereas pagenodes may — and often do — refer to files that don’t yet exist.)

Books and other long documents are usually organized in a structured way — at minimum they have a sequence of pages, but more often they have sections with subsequences within. Individual Pollen source files don’t know anything about how they’re connected to other files. In theory, you could maintain this information within each source file. This would be a poor use of human energy. Let the pagetree figure it out.

procedure

(pagetree? possible-pagetree) → boolean?

  possible-pagetree : any/c
Test whether possible-pagetree is a valid pagetree. It must be a txexpr? where all elements are pagenode?, and each is unique within possible-pagetree (not counting the root node).

Examples:

> (pagetree? '(root index.html))

#t

> (pagetree? '(root duplicate.html duplicate.html))

#f

> (pagetree? '(root index.html "string.html"))

#f

> (define nested-ptree '(root 1.html 2.html (3.html 3a.html 3b.html)))
> (pagetree? nested-ptree)

#t

> (pagetree? `(root index.html ,nested-ptree (subsection.html more.html)))

#t

; Nesting a subtree twice creates duplication
> (pagetree? `(root index.html ,nested-ptree (subsection.html ,nested-ptree)))

#f

procedure

(validate-pagetree possible-pagetree) → pagetree?

  possible-pagetree : any/c
Like pagetree?, but raises a descriptive error if possible-pagetree is invalid, and otherwise returns possible-pagetree itself.

Examples:

> (validate-pagetree '(root (mama.html son.html daughter.html) uncle.html))

'(root (mama.html son.html daughter.html) uncle.html)

> (validate-pagetree `(root (,+ son.html daughter.html) uncle.html))

#f

> (validate-pagetree '(root (mama.html son.html son.html) mama.html))

validate-pagetree: members-unique? failed because items

aren’t unique: (son.html mama.html)

procedure

(pagenode? possible-pagenode) → boolean?

  possible-pagenode : any/c
Test whether possible-pagenode is a valid pagenode. A pagenode can be any symbol? that is not whitespace/nbsp? Every leaf of a pagetree is a pagenode. In practice, your pagenodes will likely be names of output files.

Pagenodes are symbols (rather than strings) so that pagetrees will be valid tagged X-expressions, which is a more convenient format for validation & processing.

Examples:

; Three symbols, the third one annoying but valid
> (map pagenode? '(symbol index.html |   silly   |))

'(#t #t #t)

; A number, a string, a txexpr, and a whitespace symbol
> (map pagenode? '(9.999 "index.html" (p "Hello") |    |))

'(#f #f #f #f)

procedure

(pagenodeish? v) → boolean?

  v : any/c
Return #t if v can be converted with ->pagenode.

Example:

> (map pagenodeish? '(9.999 "index.html" |    |))

'(#t #t #f)

procedure

(->pagenode v) → pagenode?

  v : pagenodeish?
Convert v to a pagenode.

Examples:

> (map pagenodeish? '(symbol 9.999 "index.html" |  silly  |))

'(#t #t #t #t)

> (map ->pagenode '(symbol 9.999 "index.html" |  silly  |))

'(symbol |9.999| index.html |  silly  |)

11.4.1 Navigation

parameter

(current-pagetree) → pagetree?

(current-pagetree pagetree) → void?
  pagetree : pagetree?
A parameter that defines the default pagetree used by pagetree navigation functions (e.g., parent-pagenode, chidren, et al.) if another is not explicitly specified. Initialized to #f.

procedure

(parent p [pagetree]) → (or/c #f pagenode?)

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)
Find the parent pagenode of p within pagetree. Return #f if there isn’t one.

Examples:

> (current-pagetree '(root (mama.html son.html daughter.html) uncle.html))
> (parent 'son.html)

'mama.html

> (parent "mama.html")

'root

> (parent (parent 'son.html))

'root

> (parent (parent (parent 'son.html)))

#f

procedure

(children p [pagetree]) → (or/c #f pagenode?)

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)
Find the child pagenodes of p within pagetree. Return #f if there aren’t any.

Examples:

> (current-pagetree '(root (mama.html son.html daughter.html) uncle.html))
> (children 'mama.html)

'(son.html daughter.html)

> (children 'uncle.html)

#f

> (children 'root)

'(mama.html uncle.html)

> (map children (children 'root))

'((son.html daughter.html) #f)

procedure

(siblings p [pagetree]) → (or/c #f pagenode?)

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)
Find the sibling pagenodes of p within pagetree. The list will include p itself. But the function will still return #f if pagetree is #f.

Examples:

> (current-pagetree '(root (mama.html son.html daughter.html) uncle.html))
> (siblings 'son.html)

'(son.html daughter.html)

> (siblings 'daughter.html)

'(son.html daughter.html)

> (siblings 'mama.html)

'(mama.html uncle.html)

procedure

(previous p [pagetree]) → (or/c #f pagenode?)

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)

procedure

(previous* p [pagetree]) → (or/c #f (listof pagenode?))

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)
Return the pagenode immediately before p. For previous*, return all the pagenodes before p, in sequence. In both cases, return #f if there aren’t any pagenodes. The root pagenode is ignored.

Examples:

> (current-pagetree '(root (mama.html son.html daughter.html) uncle.html))
> (previous 'daughter.html)

'son.html

> (previous 'son.html)

'mama.html

> (previous (previous 'daughter.html))

'mama.html

> (previous 'mama.html)

#f

> (previous* 'daughter.html)

'(mama.html son.html)

> (previous* 'uncle.html)

'(mama.html son.html daughter.html)

procedure

(next p [pagetree]) → (or/c #f pagenode?)

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)

procedure

(next* p [pagetree]) → (or/c #f (listof pagenode?))

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)
Return the pagenode immediately after p. For next*, return all the pagenodes after p, in sequence. In both cases, return #f if there aren’t any pagenodes. The root pagenode is ignored.

Examples:

> (current-pagetree '(root (mama.html son.html daughter.html) uncle.html))
> (next 'son.html)

'daughter.html

> (next 'daughter.html)

'uncle.html

> (next (next 'son.html))

'uncle.html

> (next 'uncle.html)

#f

> (next* 'mama.html)

'(son.html daughter.html uncle.html)

> (next* 'daughter.html)

'(uncle.html)

11.4.2 Utilities

procedure

(pagetree->list pagetree) → list?

  pagetree : pagetree?
Convert pagetree to a simple list. Equivalent to a pre-order depth-first traversal of pagetree.

procedure

(in-pagetree? pagenode [pagetree]) → boolean?

  pagenode : pagenode?
  pagetree : pagetree? = (current-pagetree)
Report whether pagenode is in pagetree.

procedure

(path->pagenode p) → pagenode?

  p : pathish?
Convert path p to a pagenode — meaning, make it relative to current-project-root, run it through ->output-path, and convert it to a symbol. Does not tell you whether the resultant pagenode actually exists in the current pagetree (for that, use in-pagetree?).

    ← prev  up  next → 
 
\ No newline at end of file +11.4 Pagetree
►Pollen:   the book is a program
▼11 Module reference
11.1 Cache
11.2 Decode
11.3 File
11.4 Pagetree
11.5 Render
11.6 Template
11.7 Tag
11.8 Top
11.9 World
►11.4 Pagetree
On this page:
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
11.4.6.1 Predicates & validation
pagetree?
validate-pagetree
pagenode?
pagenodeish?
->pagenode
11.4.6.2 Navigation
current-pagetree
parent
children
siblings
previous
previous*
next
next*
11.4.6.3 Utilities
pagetree->list
in-pagetree?
path->pagenode
6.1.0.5
    ← prev  up  next → 

11.4 Pagetree

 (require pollen/pagetree) package: pollen

Books and other long documents are usually organized in a structured way — at minimum they have a sequence of pages, but more often they have sections with subsequences within. Individual pages in a Pollen project don’t know anything about how they’re connected to other pages. In theory, you could maintain this information within the source files. But this would be a poor use of human energy.

Instead, use a pagetree. A pagetree is a simple abstraction for defining & working with sequences of pagenodes. Typically these pagenodes will be the names of output files in your project.

“So it’s a list of web-page filenames?” Sort of. When I think of a web page, I think of an actual file on a disk. Keeping with Pollen’s orientation toward dynamic rendering, pagenodes may — and often do — refer to files that don’t yet exist. Moreover, by referring to output names rather than source names, you retain the flexibility to change the kind of source associated with a particular pagenode (e.g., from preprocessor source to Pollen markup).

Pagetrees can be flat or hierarchical. A flat pagetree is just a list of pagenodes. A hierarchical pagetree can also contain recursively nested lists of pagenodes. But you needn’t pay attention to this distinction, as the pagetree functions don’t care which kind you use. Neither do I.

Pagetrees surface throughout the Pollen system. They’re primarily used for navigation — for instance, calculating “previous,” “next,” or “up” links for a given page. A special pagetree, index.ptree, is used by the project server to order the files in a dashboard. Pagetrees can also be used to define batches of files for certain operations, for instance raco pollen render. You might find other uses for them too.

11.4.1 Making pagetrees with a source file

A pagetree source file either starts with #lang pollen and uses the .ptree extension, or starts with #lang pollen/ptree and then can have any file extension.

Unlike other Pollen source files, since the pagetree source is not rendered into an output format, the rest of the filename is up to you.

Here’s a flat pagetree. Each line is considered a single pagenode (blank lines are ignored). Notice that no Pollen command syntax nor quoting is needed within the pagetree source:

"flat.ptree"
#lang pollen
 
index.html
introduction.html
main_argument.html
conclusion.html

And here’s the output in DrRacket:

'(pagetree-root index.html introduction.html main_argument.html conclusion.html)

Keeping with usual Pollen policy, this is an X-expression. The pagetree-root is just an arbitrary tag that contains the pagetree.

Upgrading to a hierarchical pagetree is simple. The same basic rule applies — one pagenode per line. But this time, you add Pollen command syntax: a lozenge ◊ in front of a pagenode marks it as the top of a nested list, and the sub-pagenodes of that list go between { curly braces }, like so:

"hierarchical.ptree"
#lang pollen
 
toc.html
◊first-chapter.html{
    foreword.html
    introduction.html}
◊second-chapter.html{
    ◊main-argument.html{
        facts.html
        analysis.html}
    conclusion.html}
bibliography.html

The output of our hierarchical pagetree:

'(pagetree-root toc.html (first-chapter.html foreword.html introduction.html) (second-chapter.html (main-argument.html facts.html analysis.html) conclusion.html) bibliography.html)

One advantage of using a source file is that when you run it in DrRacket, it will automatically be checked using validate-pagetree, which insures that every element in the pagetree meets pagenode?, and that all the pagenodes are unique.

This pagetree has a duplicate pagenode, so it won’t run:

"duplicate-pagenode.ptree"
#lang pollen
 
index.html
introduction.html
main_argument.html
conclusion.html
index.html

Instead, you’ll get an error:

validate-pagetree: members-unique? failed because item isn’t unique: (index.html)

11.4.2 Making pagetrees by hand

Experienced programmers may want to know that because a pagetree is just an X-expression, you can synthesize a pagetree using any Pollen or Racket tools for making X-expressions. For example, here’s some Racket code that generates the same pagetree as the flat.ptree source file above:

"make-flat-ptree.rkt"
#lang racket
(require pollen/pagetree)
(define node-names '(index introduction main_argument conclusion))
(define pt `(pagetree-root
  ,@(map (λ(n) (string->symbol (format "~a.html" n))) node-names)))
(if (pagetree? pt) pt "Oops, not a pagetree")

Note that you need to take more care when building a pagetree by hand. Pagenodes are symbols, not strings, thus the use of string->symbol is mandatory. One benefit of using a pagetree source file is that it takes care of this housekeeping for you.

11.4.3 Using pagetrees for navigation

Typically you’ll call the pagetree-navigation functions from inside templates, using the special variable here as the starting point. For more on this technique, see pagetree navigation.

11.4.4 Using index.ptree in the dashboard

When you’re using the project server to view the files in a directory, the server will first look for a file called index.ptree. If it finds this pagetree file, it will use it to build the dashboard. If not, then it will synthesize a pagetree using a directory listing. For more on this technique, see Using the dashboard.

11.4.5 Using pagetrees with raco pollen render

The raco pollen render command is used to regenerate an output file from its source. If you pass a pagetree to raco pollen render, it will automatically render each file listed in the pagetree.

For instance, many projects have auxiliary pages that don’t really belong in the main navigational flow. You can collect these pages in a separate pagetree:

"utility.ptree"
#lang pollen
 
404-error.html
terms-of-service.html
webmaster.html
[... and so on]

Thus, when you’re using pagetree-navigation functions within a template, you can use your main pagetree, and restrict the navigation to the main editorial content. But when you render the project, you can pass both pagetrees to raco pollen render.

For more on this technique, see raco pollen render.

11.4.6 Functions
11.4.6.1 Predicates & validation

procedure

(pagetree? possible-pagetree) → boolean?

  possible-pagetree : any/c
Test whether possible-pagetree is a valid pagetree. It must be a txexpr? where all elements are pagenode?, and each is unique within possible-pagetree (not counting the root node).

Examples:

> (pagetree? '(root index.html))

#t

> (pagetree? '(root duplicate.html duplicate.html))

#f

> (pagetree? '(root index.html "string.html"))

#f

> (define nested-ptree '(root 1.html 2.html (3.html 3a.html 3b.html)))
> (pagetree? nested-ptree)

#t

> (pagetree? `(root index.html ,nested-ptree (subsection.html more.html)))

#t

; Nesting a subtree twice creates duplication
> (pagetree? `(root index.html ,nested-ptree (subsection.html ,nested-ptree)))

#f

procedure

(validate-pagetree possible-pagetree) → pagetree?

  possible-pagetree : any/c
Like pagetree?, but raises a descriptive error if possible-pagetree is invalid, and otherwise returns possible-pagetree itself.

Examples:

> (validate-pagetree '(root (mama.html son.html daughter.html) uncle.html))

'(root (mama.html son.html daughter.html) uncle.html)

> (validate-pagetree `(root (,+ son.html daughter.html) uncle.html))

#f

> (validate-pagetree '(root (mama.html son.html son.html) mama.html))

validate-pagetree: members-unique? failed because items

aren’t unique: (son.html mama.html)

procedure

(pagenode? possible-pagenode) → boolean?

  possible-pagenode : any/c
Test whether possible-pagenode is a valid pagenode. A pagenode can be any symbol? that is not whitespace/nbsp? Every leaf of a pagetree is a pagenode. In practice, your pagenodes will likely be names of output files.

Pagenodes are symbols (rather than strings) so that pagetrees will be valid tagged X-expressions, which is a more convenient format for validation & processing.

Examples:

; Three symbols, the third one annoying but valid
> (map pagenode? '(symbol index.html |   silly   |))

'(#t #t #t)

; A number, a string, a txexpr, and a whitespace symbol
> (map pagenode? '(9.999 "index.html" (p "Hello") |    |))

'(#f #f #f #f)

procedure

(pagenodeish? v) → boolean?

  v : any/c
Return #t if v can be converted with ->pagenode.

Example:

> (map pagenodeish? '(9.999 "index.html" |    |))

'(#t #t #f)

procedure

(->pagenode v) → pagenode?

  v : pagenodeish?
Convert v to a pagenode.

Examples:

> (map pagenodeish? '(symbol 9.999 "index.html" |  silly  |))

'(#t #t #t #t)

> (map ->pagenode '(symbol 9.999 "index.html" |  silly  |))

'(symbol |9.999| index.html |  silly  |)

11.4.6.2 Navigation

parameter

(current-pagetree) → pagetree?

(current-pagetree pagetree) → void?
  pagetree : pagetree?
A parameter that defines the default pagetree used by pagetree navigation functions (e.g., parent-pagenode, chidren, et al.) if another is not explicitly specified. Initialized to #f.

procedure

(parent p [pagetree]) → (or/c #f pagenode?)

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)
Find the parent pagenode of p within pagetree. Return #f if there isn’t one.

Examples:

> (current-pagetree '(root (mama.html son.html daughter.html) uncle.html))
> (parent 'son.html)

'mama.html

> (parent "mama.html")

'root

> (parent (parent 'son.html))

'root

> (parent (parent (parent 'son.html)))

#f

procedure

(children p [pagetree]) → (or/c #f pagenode?)

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)
Find the child pagenodes of p within pagetree. Return #f if there aren’t any.

Examples:

> (current-pagetree '(root (mama.html son.html daughter.html) uncle.html))
> (children 'mama.html)

'(son.html daughter.html)

> (children 'uncle.html)

#f

> (children 'root)

'(mama.html uncle.html)

> (map children (children 'root))

'((son.html daughter.html) #f)

procedure

(siblings p [pagetree]) → (or/c #f pagenode?)

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)
Find the sibling pagenodes of p within pagetree. The list will include p itself. But the function will still return #f if pagetree is #f.

Examples:

> (current-pagetree '(root (mama.html son.html daughter.html) uncle.html))
> (siblings 'son.html)

'(son.html daughter.html)

> (siblings 'daughter.html)

'(son.html daughter.html)

> (siblings 'mama.html)

'(mama.html uncle.html)

procedure

(previous p [pagetree]) → (or/c #f pagenode?)

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)

procedure

(previous* p [pagetree]) → (or/c #f (listof pagenode?))

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)
Return the pagenode immediately before p. For previous*, return all the pagenodes before p, in sequence. In both cases, return #f if there aren’t any pagenodes. The root pagenode is ignored.

Examples:

> (current-pagetree '(root (mama.html son.html daughter.html) uncle.html))
> (previous 'daughter.html)

'son.html

> (previous 'son.html)

'mama.html

> (previous (previous 'daughter.html))

'mama.html

> (previous 'mama.html)

#f

> (previous* 'daughter.html)

'(mama.html son.html)

> (previous* 'uncle.html)

'(mama.html son.html daughter.html)

procedure

(next p [pagetree]) → (or/c #f pagenode?)

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)

procedure

(next* p [pagetree]) → (or/c #f (listof pagenode?))

  p : (or/c #f pagenodeish?)
  pagetree : pagetree? = (current-pagetree)
Return the pagenode immediately after p. For next*, return all the pagenodes after p, in sequence. In both cases, return #f if there aren’t any pagenodes. The root pagenode is ignored.

Examples:

> (current-pagetree '(root (mama.html son.html daughter.html) uncle.html))
> (next 'son.html)

'daughter.html

> (next 'daughter.html)

'uncle.html

> (next (next 'son.html))

'uncle.html

> (next 'uncle.html)

#f

> (next* 'mama.html)

'(son.html daughter.html uncle.html)

> (next* 'daughter.html)

'(uncle.html)

11.4.6.3 Utilities

procedure

(pagetree->list pagetree) → list?

  pagetree : pagetree?
Convert pagetree to a simple list. Equivalent to a pre-order depth-first traversal of pagetree.

procedure

(in-pagetree? pagenode [pagetree]) → boolean?

  pagenode : pagenode?
  pagetree : pagetree? = (current-pagetree)
Report whether pagenode is in pagetree.

procedure

(path->pagenode p) → pagenode?

  p : pathish?
Convert path p to a pagenode — meaning, make it relative to current-project-root, run it through ->output-path, and convert it to a symbol. Does not tell you whether the resultant pagenode actually exists in the current pagetree (for that, use in-pagetree?).

    ← prev  up  next → 
 
\ No newline at end of file diff --git a/doc/doc-index.html b/doc/doc-index.html index 5f5749b..3da9259 100644 --- a/doc/doc-index.html +++ b/doc/doc-index.html @@ -1,2 +1,2 @@ -Index
▼Pollen:   the book is a program
    ← prev  up  next → 

Index

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

 

“But I really need XML…”
“Now you have two problems”
#%top
->html
->markup-source-path
->null-source-path
->output-path
->pagenode
->preproc-source-path
->scribble-source-path
->template-source-path
A special data structure for HTML
Acknowledgments
Adding commands
Adding navigation links to the template with here
Any command is valid
Attaching behavior to tags
Attributes
Authoring mode
Backstory
Block
block-txexpr?
Cache
cache-ref
cached-require
children
Choosing custom tags
Command syntax using ◊
Creating a Pollen markup file
Creating a source file
Creating valid HTML output
current-cache
current-pagetree
Custom exports
Decode
decode
def/c
Defining variables with commands
detect-linebreaks
detect-paragraphs
Development environment
Enter Racket
File
File formats
First tutorial
First tutorial complete
Format independence
Further reading
get-template-for
Handling navigation boundaries with conditionals
has-markup-source?
has-null-source?
has-preproc-source?
has-scribble-source?
has-template-source?
has/is-markup-source?
has/is-null-source?
has/is-preproc-source?
has/is-scribble-source?
has/is-template-source?
in-pagetree?
index.ptree & the project server
Inserting a comment
Inserting specific source data into templates
Inserting the value of a variable
Inserting values from variables
Inserting variables within CSS
Installation
Intermission
Intermission
Intermission
Interpolating variables into strings
Invoking other functions
Invoking tag functions
License & source code
Linking to an external CSS file
make-cache
make-default-tag-function
Making a custom template
Making a pagetree file
Making sure raco pollen works
Markdown (.pmd extension)
Markdown authoring mode
Markdown in Pollen: two options
Markdown mode
Markup (.pm extension)
Markup mode
markup-source?
Module reference
Multiple input values & rest arguments
Naming, saving, and rendering a source file
Navigation
next
next*
Notes for experienced programmers
Null (.p extension)
null-source?
One language, multiple dialects
Organizing functions
pagenode?
pagenodeish?
Pagetree
Pagetree (.ptree extension)
Pagetree navigation
pagetree->list
pagetree-source?
pagetree?
Pagetrees
Pagetrees
parent
Parsing attributes
path->pagenode
Point of no return
pollen
Pollen as a preprocessor
Pollen command syntax
Pollen markup vs. XML
pollen/cache
pollen/decode
pollen/file
pollen/markdown
pollen/markup
pollen/pagetree
pollen/pre
pollen/ptree
pollen/render
pollen/tag
pollen/template
pollen/top
pollen/world
Pollen: the book is a program
Prelude: my principled objection to Markdown
preproc-source?
Preprocessor (.pp extension)
Prerequisites
Prerequisites
Prerequisites
previous
previous*
project-block-tags
PS for Scribble users
Putting in the text of the poem
Putting it all together
Quick tour
Racket basics (if you’re not familiar)
raco pollen
raco pollen clone
raco pollen help
raco pollen render
raco pollen start
register-block-tag
Render
render
render-batch
render-pagetree
render-to-file
render-to-file-if-needed
reset-cache
Rethinking the solution for digital books
Returning an X-expression
Running a source file
Saving & naming your source file
Scribble (.scrbl extension)
scribble-source?
Second tutorial
Second tutorial complete
select
select*
select-from-doc
select-from-metas
Semantic markup
Setting the #lang line
Setting up a preprocessor source file
siblings
smart-dashes
smart-quotes
Source files in the dashboard
Source formats
split-attributes
Standard exports
Starting a new file in DrRacket
Starting the project server with raco pollen
Tag
Tags & tag functions
Tags are functions
Template
template-source?
Templated source files
Templates
Templates
The ->html function and the doc variable
The better idea: a programming model
The big picture
The book is a program
The command name
The directory-require.rkt file
The directory-require.rkt file
The end of the beginning
The golden rule
The lozenge glyph (◊)
The preprocessor
The project server
The Racket arguments
The relationship of Racket & Pollen
The text argument
The two command modes: text mode & Racket mode
The XML problem
Third tutorial
Top
Typography
Using custom tags
Using Markdown with the preprocessor
Using Racket’s function libraries
Using raco pollen
Using the automatic pagetree
Using the dashboard
Using the project server
Utilities
Utility formats
validate-pagetree
Web development and its discontents
What are custom tags good for?
What is Pollen?
What Pollen markup does differently
when/block
whitespace/nbsp?
whitespace?
Working with the preprocessor
World
world:check-directory-requires-in-render?
world:command-marker
world:current-server-extras-path
world:current-server-port
world:dashboard-css
world:decodable-extensions
world:default-pagetree
world:default-port
world:default-template-prefix
world:directory-require
world:fallback-template-prefix
world:linebreak-separator
world:main-pollen-export
world:markdown-source-ext
world:markup-source-ext
world:meta-pollen-export
world:mode-auto
world:mode-markdown
world:mode-markup
world:mode-pagetree
world:mode-preproc
world:newline
world:null-source-ext
world:pagetree-root-node
world:pagetree-source-ext
world:paragraph-separator
world:paths-excluded-from-dashboard
world:preproc-source-ext
world:scribble-source-ext
world:server-extras-dir
world:template-meta-key
world:template-source-ext
wrap-hanging-quotes
Writing with Pollen markup
X-expressions
◊ command overview

    ← prev  up  next → 
 
\ No newline at end of file +Index
▼Pollen:   the book is a program
    ← prev  up  next → 

Index

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

 

“But I really need XML…”
“Now you have two problems”
#%top
->html
->markup-source-path
->null-source-path
->output-path
->pagenode
->preproc-source-path
->scribble-source-path
->template-source-path
A special data structure for HTML
Acknowledgments
Adding commands
Adding navigation links to the template with here
Any command is valid
Attaching behavior to tags
Attributes
Authoring mode
Backstory
Block
block-txexpr?
Cache
cache-ref
cached-require
children
Choosing custom tags
Command syntax using ◊
Creating a Pollen markup file
Creating a source file
Creating valid HTML output
current-cache
current-pagetree
Custom exports
Decode
decode
def/c
Defining variables with commands
detect-linebreaks
detect-paragraphs
Development environment
Enter Racket
File
File formats
First tutorial
First tutorial complete
Format independence
Functions
Further reading
get-template-for
Handling navigation boundaries with conditionals
has-markup-source?
has-null-source?
has-preproc-source?
has-scribble-source?
has-template-source?
has/is-markup-source?
has/is-null-source?
has/is-preproc-source?
has/is-scribble-source?
has/is-template-source?
in-pagetree?
index.ptree & the project server
Inserting a comment
Inserting specific source data into templates
Inserting the value of a variable
Inserting values from variables
Inserting variables within CSS
Installation
Intermission
Intermission
Intermission
Interpolating variables into strings
Invoking other functions
Invoking tag functions
License & source code
Linking to an external CSS file
make-cache
make-default-tag-function
Making a custom template
Making a pagetree file
Making pagetrees by hand
Making pagetrees with a source file
Making sure raco pollen works
Markdown (.pmd extension)
Markdown authoring mode
Markdown in Pollen: two options
Markdown mode
Markup (.pm extension)
Markup mode
markup-source?
Module reference
Multiple input values & rest arguments
Naming, saving, and rendering a source file
Navigation
next
next*
Notes for experienced programmers
Null (.p extension)
null-source?
One language, multiple dialects
Organizing functions
pagenode?
pagenodeish?
Pagetree
Pagetree (.ptree extension)
Pagetree navigation
pagetree->list
pagetree-source?
pagetree?
Pagetrees
Pagetrees
parent
Parsing attributes
path->pagenode
Point of no return
pollen
Pollen as a preprocessor
Pollen command syntax
Pollen markup vs. XML
pollen/cache
pollen/decode
pollen/file
pollen/markdown
pollen/markup
pollen/pagetree
pollen/pre
pollen/ptree
pollen/render
pollen/tag
pollen/template
pollen/top
pollen/world
Pollen: the book is a program
Predicates & validation
Prelude: my principled objection to Markdown
preproc-source?
Preprocessor (.pp extension)
Prerequisites
Prerequisites
Prerequisites
previous
previous*
project-block-tags
PS for Scribble users
Putting in the text of the poem
Putting it all together
Quick tour
Racket basics (if you’re not familiar)
raco pollen
raco pollen clone
raco pollen help
raco pollen render
raco pollen start
register-block-tag
Render
render
render-batch
render-pagetree
render-to-file
render-to-file-if-needed
reset-cache
Rethinking the solution for digital books
Returning an X-expression
Running a source file
Saving & naming your source file
Scribble (.scrbl extension)
scribble-source?
Second tutorial
Second tutorial complete
select
select*
select-from-doc
select-from-metas
Semantic markup
Setting the #lang line
Setting up a preprocessor source file
siblings
smart-dashes
smart-quotes
Source files in the dashboard
Source formats
split-attributes
Standard exports
Starting a new file in DrRacket
Starting the project server with raco pollen
Tag
Tags & tag functions
Tags are functions
Template
template-source?
Templated source files
Templates
Templates
The ->html function and the doc variable
The better idea: a programming model
The big picture
The book is a program
The command name
The directory-require.rkt file
The directory-require.rkt file
The end of the beginning
The golden rule
The lozenge glyph (◊)
The preprocessor
The project server
The Racket arguments
The relationship of Racket & Pollen
The text argument
The two command modes: text mode & Racket mode
The XML problem
Third tutorial
Top
Typography
Using custom tags
Using index.ptree in the dashboard
Using Markdown with the preprocessor
Using pagetrees for navigation
Using pagetrees with raco pollen render
Using Racket’s function libraries
Using raco pollen
Using the automatic pagetree
Using the dashboard
Using the project server
Utilities
Utility formats
validate-pagetree
Web development and its discontents
What are custom tags good for?
What is Pollen?
What Pollen markup does differently
when/block
whitespace/nbsp?
whitespace?
Working with the preprocessor
World
world:check-directory-requires-in-render?
world:command-marker
world:current-server-extras-path
world:current-server-port
world:dashboard-css
world:decodable-extensions
world:default-pagetree
world:default-port
world:default-template-prefix
world:directory-require
world:fallback-template-prefix
world:linebreak-separator
world:main-pollen-export
world:markdown-source-ext
world:markup-source-ext
world:meta-pollen-export
world:mode-auto
world:mode-markdown
world:mode-markup
world:mode-pagetree
world:mode-preproc
world:newline
world:null-source-ext
world:pagetree-root-node
world:pagetree-source-ext
world:paragraph-separator
world:paths-excluded-from-dashboard
world:preproc-source-ext
world:scribble-source-ext
world:server-extras-dir
world:template-meta-key
world:template-source-ext
wrap-hanging-quotes
Writing with Pollen markup
X-expressions
◊ command overview

    ← prev  up  next → 
 
\ No newline at end of file diff --git a/doc/index.html b/doc/index.html index c7531d1..edfafe1 100644 --- a/doc/index.html +++ b/doc/index.html @@ -1,3 +1,3 @@ Pollen: the book is a program
▼Pollen:   the book is a program
On this page:
Pollen:   the book is a program
6.1.0.5
    ← prev  up  next → 

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?

    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 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

          7.4.2.1 Point of no return

          7.4.2.2 Multiple input values & rest arguments

          7.4.2.3 Returning an X-expression

          7.4.2.4 Interpolating variables into strings

          7.4.2.5 Parsing attributes

      7.5 Intermission

      7.6 Organizing functions

        7.6.1 Using Racket’s function libraries

        7.6.2 The directory-require.rkt file

      7.7 Putting it all together

    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

          10.3.1.1 Invoking tag functions

          10.3.1.2 Invoking other functions

          10.3.1.3 Inserting the value of a variable

          10.3.1.4 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 Navigation

        11.4.2 Utilities

      11.5 Render

      11.6 Template

      11.7 Tag

      11.8 Top

      11.9 World

    12 Acknowledgments

    13 License & source code

    Index

    ← prev  up  next → 
 
\ No newline at end of file +

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?

    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 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

          7.4.2.1 Point of no return

          7.4.2.2 Multiple input values & rest arguments

          7.4.2.3 Returning an X-expression

          7.4.2.4 Interpolating variables into strings

          7.4.2.5 Parsing attributes

      7.5 Intermission

      7.6 Organizing functions

        7.6.1 Using Racket’s function libraries

        7.6.2 The directory-require.rkt file

      7.7 Putting it all together

    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

          10.3.1.1 Invoking tag functions

          10.3.1.2 Invoking other functions

          10.3.1.3 Inserting the value of a variable

          10.3.1.4 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

          11.4.6.1 Predicates & validation

          11.4.6.2 Navigation

          11.4.6.3 Utilities

      11.5 Render

      11.6 Template

      11.7 Tag

      11.8 Top

      11.9 World

    12 Acknowledgments

    13 License & source code

    Index

    ← prev  up  next → 
 
\ No newline at end of file diff --git a/scribblings/pagetree.scrbl b/scribblings/pagetree.scrbl index 7aedc8a..2dffb0a 100644 --- a/scribblings/pagetree.scrbl +++ b/scribblings/pagetree.scrbl @@ -1,6 +1,6 @@ #lang scribble/manual -@(require scribble/eval pollen/cache pollen/world (for-label racket (except-in pollen #%module-begin) pollen/world txexpr pollen/decode pollen/file sugar)) +@(require "mb-tools.rkt" scribble/eval pollen/cache pollen/world (for-label racket (except-in pollen #%module-begin) pollen/world txexpr pollen/decode pollen/file sugar pollen/pagetree)) @(define my-eval (make-base-eval)) @(my-eval `(require pollen pollen/pagetree txexpr)) @@ -9,11 +9,128 @@ @defmodule[pollen/pagetree] -A @italic{pagetree} is a hierarchical list of Pollen output files. A pagetree source file has the extension @code[(format ".~a" world:pagetree-source-ext)]. A pagetree provides a convenient way of separating the structure of the pages from the page sources, and navigating around this structure. +Books and other long documents are usually organized in a structured way — at minimum they have a sequence of pages, but more often they have sections with subsequences within. Individual pages in a Pollen project don't know anything about how they're connected to other pages. In theory, you could maintain this information within the source files. But this would be a poor use of human energy. -Pagetrees are made of @italic{pagenodes}. Usually these pagenodes will be names of output files in your project. (If you think it would've been more logical to just call them ``pages,'' perhaps. When I think of a web page, I think of a file on a disk. Whereas pagenodes may — and often do — refer to files that don't yet exist.) +Instead, use a pagetree. A @italic{pagetree} is a simple abstraction for defining & working with sequences of @italic{pagenodes}. Typically these pagenodes will be the names of output files in your project. + +``So it's a list of web-page filenames?'' Sort of. When I think of a web page, I think of an actual file on a disk. Keeping with Pollen's orientation toward dynamic rendering, pagenodes may — and often do — refer to files that don't yet exist. Moreover, by referring to output names rather than source names, you retain the flexibility to change the kind of source associated with a particular pagenode (e.g., from preprocessor source to Pollen markup). + +Pagetrees can be flat or hierarchical. A flat pagetree is just a @seclink["Lists__Iteration__and_Recursion" +#:doc '(lib "scribblings/guide/guide.scrbl")]{list} of pagenodes. A hierarchical pagetree can also contain recursively nested lists of pagenodes. But you needn't pay attention to this distinction, as the pagetree functions don't care which kind you use. Neither do I. + +Pagetrees surface throughout the Pollen system. They're primarily used for navigation — for instance, calculating ``previous,'' ``next,'' or ``up'' links for a given page. A special pagetree, @racketfont{index.ptree}, is used by the project server to order the files in a dashboard. Pagetrees can also be used to define batches of files for certain operations, for instance @secref["raco_pollen_render" #:doc '(lib "pollen/scribblings/pollen.scrbl")]. You might find other uses for them too. + + + +@section{Making pagetrees with a source file} + +A pagetree source file either starts with @code{#lang pollen} and uses the @racketfont{@(format ".~a" world:pagetree-source-ext)} extension, or starts with @code{#lang pollen/ptree} and then can have any file extension. + +Unlike other Pollen source files, since the pagetree source is not rendered into an output format, the rest of the filename is up to you. + +Here's a flat pagetree. Each line is considered a single pagenode (blank lines are ignored). Notice that no Pollen command syntax nor quoting is needed within the pagetree source: + +@fileblock["flat.ptree" @codeblock{ +#lang pollen + +index.html +introduction.html +main_argument.html +conclusion.html +}] + +And here's the output in DrRacket: + +@repl-output{'(pagetree-root index.html introduction.html main_argument.html conclusion.html)} + +Keeping with usual Pollen policy, this is an @seclink["X-expressions" #:doc '(lib "pollen/scribblings/pollen.scrbl")]{X-expression}. The @racket[pagetree-root] is just an arbitrary tag that contains the pagetree. + +Upgrading to a hierarchical pagetree is simple. The same basic rule applies — one pagenode per line. But this time, you add Pollen command syntax: a lozenge @litchar{◊} in front of a pagenode marks it as the top of a nested list, and the sub-pagenodes of that list go between @litchar{@"{"} curly braces @litchar{@"}"}, like so: + +@fileblock["hierarchical.ptree" @codeblock{ +#lang pollen + +toc.html +◊first-chapter.html{ + foreword.html + introduction.html} +◊second-chapter.html{ + ◊main-argument.html{ + facts.html + analysis.html} + conclusion.html} +bibliography.html +}] + +The output of our hierarchical pagetree: + +@repl-output{'(pagetree-root toc.html (first-chapter.html foreword.html introduction.html) (second-chapter.html (main-argument.html facts.html analysis.html) conclusion.html) bibliography.html)} + +One advantage of using a source file is that when you run it in DrRacket, it will automatically be checked using @racket[validate-pagetree], which insures that every element in the pagetree meets @racket[pagenode?], and that all the pagenodes are unique. + +This pagetree has a duplicate pagenode, so it won't run: + +@fileblock["duplicate-pagenode.ptree" @codeblock{ +#lang pollen + +index.html +introduction.html +main_argument.html +conclusion.html +index.html +}] + +Instead, you'll get an error: + +@errorblock{validate-pagetree: members-unique? failed because item isn’t unique: (index.html)} + +@section{Making pagetrees by hand} + +Experienced programmers may want to know that because a pagetree is just an X-expression, you can synthesize a pagetree using any Pollen or Racket tools for making X-expressions. For example, here's some Racket code that generates the same pagetree as the @racketfont{flat.ptree} source file above: + +@fileblock["make-flat-ptree.rkt" @codeblock{ +#lang racket +(require pollen/pagetree) +(define node-names '(index introduction main_argument conclusion)) +(define pt `(pagetree-root + ,@"@"(map (λ(n) (string->symbol (format "~a.html" n))) node-names))) +(if (pagetree? pt) pt "Oops, not a pagetree") +}] + +Note that you need to take more care when building a pagetree by hand. Pagenodes are symbols, not strings, thus the use of @racket[string->symbol] is mandatory. One benefit of using a pagetree source file is that it takes care of this housekeeping for you. + +@section{Using pagetrees for navigation} + +Typically you'll call the pagetree-navigation functions from inside templates, using the special variable @racket[here] as the starting point. For more on this technique, see @seclink["Pagetrees" #:doc '(lib "pollen/scribblings/pollen.scrbl")]{pagetree navigation}. + +@section{Using @racketfont{index.ptree} in the dashboard} + +When you're using the project server to view the files in a directory, the server will first look for a file called @racketfont{index.ptree}. If it finds this pagetree file, it will use it to build the dashboard. If not, then it will synthesize a pagetree using a directory listing. For more on this technique, see @secref["Using_the_dashboard" #:doc '(lib "pollen/scribblings/pollen.scrbl")]. + +@section{Using pagetrees with @exec{raco pollen render}} + +The @exec{raco pollen render} command is used to regenerate an output file from its source. If you pass a pagetree to @exec{raco pollen render}, it will automatically render each file listed in the pagetree. + +For instance, many projects have auxiliary pages that don't really belong in the main navigational flow. You can collect these pages in a separate pagetree: + +@fileblock["utility.ptree" @codeblock{ +#lang pollen + +404-error.html +terms-of-service.html +webmaster.html +[... and so on] +}] + +Thus, when you're using pagetree-navigation functions within a template, you can use your main pagetree, and restrict the navigation to the main editorial content. But when you render the project, you can pass both pagetrees to @exec{raco pollen render}. + +For more on this technique, see @secref["raco_pollen_render" #:doc '(lib "pollen/scribblings/pollen.scrbl")]. + + +@section{Functions} + +@subsection{Predicates & validation} -Books and other long documents are usually organized in a structured way — at minimum they have a sequence of pages, but more often they have sections with subsequences within. Individual Pollen source files don't know anything about how they're connected to other files. In theory, you could maintain this information within each source file. This would be a poor use of human energy. Let the pagetree figure it out. @defproc[ (pagetree? @@ -85,7 +202,7 @@ Convert @racket[_v] to a pagenode. -@section{Navigation} +@subsection{Navigation} @defparam[current-pagetree pagetree pagetree?]{ @@ -190,7 +307,7 @@ Return the pagenode immediately after @racket[_p]. For @racket[next*], return al (next* 'daughter.html) ] -@section{Utilities} +@subsection{Utilities} @defproc[ (pagetree->list