Cascading Style Sheets (CSS)
Das von den MeckWiki-Vorlagen erzeugte HTML enthält keine direkte Formatierungsanweisungen, sondern nur Struktur-Tags. Jede Formatierung erfolgt über sogenannte stylesheet-Anweisungen, die in einer CSS-Datei ausgelagert sind.
Durch das Bearbeiten dieser Datei kannst Du das Look'n'Feel Deiner Seiten weitgehend verändert: Sollen Farbe, Schriftart/-stil/-größe, Hintergrundgrafiken und die Anordnung der Elemente sind hier einstellbar. Die Netzseite CSS Zen Garden ist ein eindrucksvolles Beispiel, was man alles so machen kann.
HTML-Vorlage (simpleTAL)
MeckWiki verwendet HTML-Vorlagen, in die der strukturierte Text eingepaßt wird. Einige Beispielvorlagen sind im Programm bereits enthalten. Du kannst natürlich auch eigene Vorlagen kreieren (die Du mir dann zusenden kannst, damit ich sie in das Programm aufnehme :-)). Die verwendete Formatvorlagen-Art (engl. template engine) ist simpleTAL.
Die Formatvorlage ist eine HTML-Datei, wobei in den Tags zusätzliche Attribute vorkommen
können, die signalisieren, wie der Inhalt eingepaßt werden soll. Zum Beispiel:
<div tal:content="from">Autor kommt hierher</div>
Diese Technik hat den Vorteil, dass man die Vorlage mit einem WYSIWYG-Editor stylen kann.
Es folgen Auszüge aus der Original-Dokumentation:
simpleTAL Kommandos
tal:define
- Syntax:
- tal:define="[local | global] name expression [; define-expression...]"
- Description:
- Sets the value of „name” to „expression”. By default the name will be applicable in the „local” scope, which consists of this tag, and all other tags nested inside this tag. If the „global” keyword is used then this name will keep its value for the rest of the document.
- Example:
- <div tal:define="global title book/theTitle; local chapterTitle book/chapter/theTitle">
tal:condition
- Syntax:
- tal:condition="expression"
- Description:
- If the expression evaluates to true then this tag and all its children will be output. If the expression evaluates to false then this tag and all its children will not be included in the output.
- Example:
- <h1 tal:condition="user/firstLogin">Welcome to this page!</h1>
tal:repeat
- Syntax:
- tal:repeat="name expression"
- Description:
- Evaluates „expression”, and if it is a sequence, repeats this tag and all children once
for each item in the sequence. The „name” will be set to the value of the item in the current iteration,
and is also the name of the repeat variable. The repeat variable is accessible using the TAL path:
repeat/name and has the following properties:
- index - Iteration number starting from zero
- number - Iteration number starting from one
- even - True if this is an even iteration
- odd - True if this is an odd iteration
- start - True if this is the first item in the sequence
- end - True if this is the last item in the sequence. For iterators this is never true
- length - The length of the sequence. For iterators this is maxint as the length of an iterator is unknown
- letter - The lower case letter for this iteration, starting at „a”
- Letter - Upper case version of letter
- roman - Iteration number in Roman numerals, starting at i
- Roman - Upper case version of roman
- Example:
- <table><tr tal:repeat="fruit basket">
<td tal:content="repeat/fruit/number"></td>
<td tal:content="fruit/name"></td>
</tr></table>
tal:content
- Syntax:
- tal:content="[text | structure] expression"
- Description:
- Replaces the contents of the tag with the value of „expression”. By default, and if the „text” keyword is present, then the value of the expression will be escaped as required (i.e. characters "&<> will be escaped). If the „structure” keyword is present then the value will be output with no escaping performed.
- Example:
- <h1 tal:content="user/firstName"></h1>
tal:replace
- Syntax:
- tal:replace="[text | structure] expression"
- Description:
- Behaves identically to tal:content, except that the tag is removed from the output (as if tal:omit-tag had been used).
- Example:
- <h1>Welcome <b tal:replace="user/firstName"></b></h1>
tal:attributes
- Syntax:
- tal:attributes="name expression[;attributes-expression]"
- Description:
- Evaluates each „expression” and replaces the tag's attribute „name”. If the expression evaluates to nothing then the attribute is removed from the tag. If the expression evaluates to default then the original tag's attribute is kept. If the „expression” requires a semi-colon then it must be escaped by using „;;”.
- Example:
- <a tal:attributes="href user/homepage;title user/fullname">Your Homepage</a>
tal:omit-tag
- Syntax:
- tal:omit-tag="expression"
- Description:
- Removes the tag (leaving the tags content) if the expression evaluates to true. If expression is empty then it is taken as true.
- Example:
- <p><b tal:omit-tag="not:user/firstVisit">Welcome</b> to this page!</h1>
TALES Expressions
The expressions used in TAL are called TALES expressions. The simplest TALES expression is a path which references a value, e.g. page/body references the body property of the page object.
path
- Syntax:
- [path:]string[|TALES Expression]
- Description:
- A path, optionally starting with the modifier 'path:', references a property of an object. The '/' delimiter is used to end the name of an object and the start of the property name. Properties themselves may be objects that in turn have properties. The '|' („or”) character is used to find an alternative value to a path if the first path evaluates to 'Nothing' or does not exist.
- Example:
- <p tal:content="book/chapter/title | string:Untitled"></p>
There are several built in paths that can be used in paths:
- nothing - acts as None in Python
- default - keeps the existing value of the node (tag content or attribute value)
- options - the dictionary of values passed to the template (through the Context init method)
- repeat - access the current repeat variable (see tal:repeat)
- attrs - a dictionary of original attributes of the current tag
- CONTEXTS - a dictionary containing all of the above
Im MeckWiki-Kontext sind folgende Pfade definiert (die Namensgebung orientiert sich an der RFC822 für E-Mail-Headerlines):
- from - der Autor
- date - zuletzt geändert am
- subject - Title
- keywords - Schlagworte
- summary - Beschreibung
- template - die verwendete Vorlage
- markup - der Artikel selbst
- template_dir - der (relative) Pfad zum Layout-Ordner
- keyword_list - eine Liste von Strukturen. Jede Struktur hat ein Feld keyword (eine Zeichenkette) und ein Feld files (eine Liste). Jedes verwendete Schlagwort taucht in der Liste auf. Die Liste files ist eine Liste von Strukturen aller Dateien, wo das Schlagwort angegeben ist. Für jede Datei ist das Feld file_name und alle Meta-Informationen (from, date, subject, keywords, summary, template) verfügbar.
- template_list - eine Liste von Strukturen. Jede Struktur hat ein Feld template (eine Zeichenkette) und ein Feld files (eine Liste). Jedes verwendete Vorlage taucht in der Liste auf. Die Liste files ist eine Liste von Strukturen derjenigen Dateien, die die Vorlage verwenden. Für jede Datei ist das Feld file_name und alle Meta-Informationen (from, date, subject, keywords, summary, template) verfügbar.
Wurde ein Feld nicht ausgefüllt (z.B. keine Beschreibung), dann wird der Pfad nicht gesetzt.
exists
- Syntax:
- exists:path
- Description:
- Returns true if the path exists, false otherwise. This is particularly useful for removing tags from output when the tags will have no content.
- Example:
- <p tal:omit-tag="not:exists:book/chapter/title" tal:content="book/chapter/title"></p>
nocall
- Syntax:
- nocall:path
- Description:
- Returns a reference to a path, but without evaluating the path. Useful when you wish to define a new name to reference a function, not the current value of a function.
- Example:
- <p tal:define="title nocall:titleFunction" tal:content="title"></p>
not
- Syntax:
- not:tales-path
- Description:
- Returns the inverse of the tales-path. If the path returns true, not:path will return false.
- Example:
- <p tal:condition="not: user/firstLogin">Welcome to the site!</p>
string
- Syntax:
- string:text
- Description:
- Evaluates to a literal string with value text while substituting variables with the form ${pathName} and $pathName
- Example:
- <b tal:content="string:Welcome ${user/name}!"></b>
python
- Syntax:
- python:python-code
- Description:
- Evaluates the python-code and returns the result. The python code must be properly escaped, e.g. „python: 1 < 2” must be written as „python: 1 < 2”. The python code has access to all Python functions, including four extra functions that correspond to their TALES commands: path (string), string (string), exists (string), and nocall (string)
- Example:
- <div tal:condition="python: path (basket/items) > 1">Checkout!</div>
METAL Macro Language
METAL is a macro language commonly used with TAL & TALES. METAL allows part of a template to be used as a macro in later parts of a template, or a separate template altogether.
metal:define-macro
- Syntax:
- metal:define-macro="name"
- Description:
- Defines a new macro that can be reference later as „name”.
- Example:
- <div metal:define-macro="footer">Copyright <span tal:content="page/lastModified">2004</span></div>
metal:use-macro
- Syntax:
- metal:use-macro="expression"
- Description:
- Evaluates „expression” and uses this as a macro.
- Example:
- <div metal:use-macro="footer"></div>
metal:define-slot
- Syntax:
- metal:define-slot="name"
- Description:
- Defines a customisation point in a macro with the given name.
- Example:
-
<div metal:define-macro="footer">
<b>Standard disclaimer for the site.</b>
<i metal:define-slot="Contact">Contact admin@site.com</i>
</div>
metal:fill-slot
- Syntax:
- metal:fill-slot="name"
- Description:
- Replaces the content of a slot with this element.
- Example:
-
<div metal:use-macro="footer">
<i metal:fill-slot="Contact">Contact someone else</i>
</div>