@rshirohara/pxast

pxast

Pixiv novel Abstract Syntax Tree

---

pxast is a specification for representing pixiv novel format in a syntax tree. It implements unist.

Contents

• pxast
  • Contents
  • Introduction
  • Types
  • Nodes
    • Parent
    • Literal
    • Root
    • Paragraph
    • Heading
    • PageHeading
    • Text
    • Ruby
    • Break
    • Link
    • Image
    • PageReference
  • Content model
    • FlowContent
    • PhrasingContent
    • InlinePhrasingContent
  • License

Introduction

This document defines a format for representing pixiv novel format as an abstract syntax tree. This specification is written in a Web IDL-like grammar.

Types

If you are using TypeScript, you can use the unist types by installing them with npm:

npm install @rshirohara/pxast

Nodes

Parent

interface Parent <: UnistParent {
  children: [PxastContent]
}

Parent (UnistParent) represents an abstract interface in pxast containing other nodes (said to be children).

Its content is limited to only other pxast content.

Literal

interface Literal <: UnistLiteral {
  value: string
}

Literal (UnistLiteral) represents an abstract interface in pxast containing a value.

Its value field is a string.

Root

interface Root <: Parent {
  type: "root"
}

Root (Parent) represents a document.

Root can be used as the root of a tree, never as a child.

Paragraph

interface Paragraph <: Parent {
  type: "paragraph"
  children: [PhrasingContent]
}

Paragraph (Parent) represents a unit of discourse dealing with a particular point.

Paragraph can be used where content is expected. Its content model is phrasing content.

For example, the following text:

たとえば私はこの文章を書く。

Yields:

{
  type: "paragraph",
  children: [{ type: "text", value: "たとえば私はこの文章を書く。" }]
}

Heading

interface Heading <: Parent {
  type: "heading"
  children: [InlinePhrasingContent]
}

Heading (Parent) represents a heading of a section.

Heading can be used where flow content is expected. Its content model is inline phrasing content.

For example, the following text:

[chapter:まえがき]

Yields:

{
  type: "heading";
  children: [{ type: "text", value: "まえがき" }];
}

PageHeading

interface Page <: Node {
  type: "pageHeading"
  pageNumber: 1 <= number
}

PageHeading (Node) represents a heading of a page.

PageHeading can be used where flow content is expected. It has no content model.

A pageNumber field must be present. A value of 1 is said to be the minimum value.

For example, the following text:

ここは一ページ目。
[newpage]
ここが二ページ目。

Yields:

{
  type: "root",
  children: [
    { type: "pageHeading", pageNumber: 1 },
    {
      type: "paragraph",
      children: [{ type: "text", value: "ここは一ページ目。" }]
    },
    { type: "pageHeading", pageNumber: 2 },
    {
      type: "paragraph",
      children: [{ type: "text", value: "ここが二ページ目。" }]
    }
  ]
}

Text

interface Text <: Literal {
  type: "text"
}

Text (Literal) represents everything that is just text.

Text can be used where phrasing content is expected. Its content is represented by its value field.

For example, the following text:

たとえば私はこの文章を書く。

Yields:

{ type: "text", value: "たとえば私はこの文章を書く。" }

Ruby

interface Ruby <: Literal {
  type: "ruby"
  ruby: string
}

Ruby (Literal) represents a small annotations that are rendered above, below, or next to text.

Ruby can be used where phrasing content is expected. Its content is represented by its value and ruby fields.

For example, the following text:

[[rb:私>わたし]]

Yields:

{
  type: "ruby",
  value: "私",
  ruby: "わたし"
}

Break

interface Break <: Node {
  type: "break"
}

Break (Node) represents a line break.

Break can be used where phrasing content is expected. It has no content model.

For example, the following text:

これは一行目。
これが二行目。

Yields:

{
  type: "paragraph",
  children: [
    { type: "text", value: "これは一行目。" },
    { type: "break" },
    { type: "text", value: "これが二行目。" }
  ]
}

Link

interface Link <: Parent {
  type: "link"
  url: string
  children: [InlinePhrasingContent]
}

Link (Parent) represents a hyperlink.

Link can be used where phrasing content is expected. Its content model is inline phrasing content.

For example, the following text:

[[jumpurl:リンク例>https://example.com]]

Yields:

{
  type: "link",
  url: "https://example.com",
  children: [{ type: "text", value: "リンク例" }]
}

Image

interface Image <: Node {
  type: "image"
  illustId: string
  pageNumber: 1 <= number?
}

Image (Node) represents a reference to pixiv image.

Image can be used where phrasing content is expected. It has no content model.

For example, the following text:

[pixivimage:000001-02]

Yields:

{
  type: "image",
  illustId: "000001",
  pageNumber: 2
}

PageReference

interface PageReference <: Node {
  type: "pageReference"
  pageNumber: 1 <= number
}

PageReference (Node) represents a reference to PageHeading.

PageReference can be used where phrasing content is expected. It has no content model.

A pageNumber field must be present. A value of 1 is said to be the minimum value.

For example, the following text:

[jump:01]

Yields:

{
  type: "pageReference",
  pageNumber: 1
}

Content model

type PxastContent = FlowContent | PhrasingContent

Each node in pxast falls into one or more categories of Content that group nodes with similar characteristics together.

FlowContent

type FlowContent = Heading | PageHeading | Paragraph

Flow content represent the sections of document.

PhrasingContent

type PhrasingContent = Break | Image | Link | PageReference | InlinePhrasingContent

Phrasing content represent the text in a document, and its markup.

InlinePhrasingContent

type InlinePhrasingContent = Ruby | Text

Inline Phrasing content represent the text in a document, and its markup, that is intended to be stored in phrasing content.

License

MIT