mirror of
https://github.com/Jermolene/TiddlyWiki5
synced 2024-12-13 03:30:27 +00:00
41 lines
2.1 KiB
Plaintext
41 lines
2.1 KiB
Plaintext
chapter.of: UI and Rendering Pipeline
|
|
created: 20140717174120958
|
|
modified: 20140717202324456
|
|
sub.num: 2
|
|
tags: doc
|
|
title: Parser
|
|
|
|
The first stage of WikiText processing is the parser.
|
|
A Parser is provided by a module with ``module-type: parser`` and is responsible to transform block of text to a parse-tree.
|
|
The parse-tree consists of nested nodes like
|
|
|
|
```js
|
|
{type: "element", tag: <string>, attributes: {}, children: []} - an HTML element
|
|
{type: "text", text: <string>} - a text node
|
|
{type: "entity", entity: <string>} - an HTML entity like © for a copyright symbol
|
|
{type: "raw", html: <string>} - raw HTML
|
|
```
|
|
|
|
The core plug-in provides a recursive descent WikiText parser which loads it's individual rules from individual modules.
|
|
Thus a developer can provide additional rules by using ``module-type: wikirule``. Each rule can produce a list of parse-tree nodes.
|
|
A simple example for a wikirule producing a ``<hr>`` from ``---`` can be found in [[horizrule.js|$:/core/modules/parsers/wikiparser/rules/horizrule.js]]
|
|
|
|
HTML tags can be embedded into WikiText because of the [[html rule|$:/core/modules/parsers/wikiparser/rules/html.js]].
|
|
This rule matches HTML tag syntax and creates ``type: "element"`` nodes.
|
|
But the html-rule has another special purpose. By parsing the HTML tag syntax it implicitly parses WikiText widgets.
|
|
It the recognises them by the $ character at the beginning of the tag name and instead of producing "element" nodes
|
|
it uses the tag name for the type:
|
|
|
|
```js
|
|
{type: "list", tag: "$list", attributes: {}, children: []} - a list element
|
|
```
|
|
|
|
The [[Widgets]] part will reveal why this makes sense and how each node is transformed into a widget.
|
|
Another special characteristic of the html-rule or the parse nodes in general is the attributes property.
|
|
Attributes in the parse-tree are not stored as simple strings but they are nodes of its own to make indirect text references available as attributes as described in [[Widgets]]:
|
|
|
|
```js
|
|
{type: "string", value: <string>} - literal string
|
|
{type: "indirect", textReference: <textReference>} - indirect through a text reference
|
|
```
|