Dev:Syntactic Guidelines: Difference between revisions
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== Newly created files == | |||
=== Byte order mark (BOM) === | |||
<p>Start the file with an Byte Order Mark, see also: [http://en.wikipedia.org/wiki/Byte_order_mark Wikipedia: Byte Order Mark (BOM)]</p> | |||
<p>Visualization tip (command line tool): <tt>less $FILENAME$</tt></p> | |||
<pre><U+FEFF><?xml version="1.0" encoding="UTF-8"?></pre> | |||
=== Subversion properties and keywords === | |||
<p>see [[Dev:Subversion_Guidelines#Add_new_files|Subversion Guidelines for new files]]</p> | |||
== Camel Case == | == Camel Case == | ||
Always use camel case for all names. Don't mix with dashed naming schemas. | |||
== White spaces == | == White spaces == |
Revision as of 11:49, 5 March 2013
Newly created files
Byte order mark (BOM)
Start the file with an Byte Order Mark, see also: Wikipedia: Byte Order Mark (BOM)
Visualization tip (command line tool): less $FILENAME$
<U+FEFF><?xml version="1.0" encoding="UTF-8"?>
Subversion properties and keywords
see Subversion Guidelines for new files
Camel Case
Always use camel case for all names. Don't mix with dashed naming schemas.
White spaces
Empty end-tags
Implementation with 1 space before closing empty end-tags
example:
<xs:restriction base="xs:ID" />
Indents
Implementation with 2 spaces
example:
<xs:element name="railml"> <xs:complexType> <xs:sequence> <xs:element name="metadata" type="dc:elementContainer" minOccurs="0" /> <xs:element ref="rail:infrastructure" minOccurs="0" />
Line Breaks
Each component declaration must be followed by a line break.
example:
<xs:attributeGroup name="aPlaces"> <xs:attribute name="category" type="rail:tPlaceCategory" use="required" /> <xs:attribute name="count" type="rail:tCounter" use="required" />
There is no maximum line length
Each component has to be fully declared on one line without line breaks.
example:
<xs:schema xmlns:rail="http://www.railml.org/schemas/2009" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:dc="http://purl.org/dc/elements/1.1/" targetNamespace="http://www.railml.org/schemas/2009" elementFormDefault="qualified" version="2.0">
XML Default Values
Empty elements and attributes
see also: W3C XML Recommendation "Tags for Empty Elements"
Implementation with shortened syntax instead of extra closing tag
example:
<xs:element ref="rail:infrastructure" minOccurs="0" />
XML Schema Default Values
Optional and required attributes
see also: W3C XML Schema Recommendation "XML Representation of Attribute Declaration Schema Components"
Implementation without use="optional"
example:
<xs:attribute name="description" type="rail:tElementDescription" />
Implementation with use="required"
example:
<xs:attribute name="id" type="rail:tGenericID" use="required" />
Elements with minimum 1 or maximum 1 occurrence
see also: W3C XML Schema Recommendation "XML Representation of Element Declaration Schema Components"
Implementation without minOccurs="1"
example:
<xs:element name="train" type="rail:eTrain" maxOccurs="unbounded" />
Implementation without maxOccurs="1"
example:
<xs:element ref="rail:timetable" minOccurs="0" />
Occurence restrictions into elements
If possible, all occurence restrictions have to go into element definitions.
xs:sequence
should stand without the attributes minOccurs
and/or maxOccurs
.
example:
<xs:extension base="rail:tElementWithIDAndName"> <xs:sequence> <xs:element name="metadata" type="dc:elementContainer" minOccurs="0" /> </xs:sequence>
Pathes inside XML documents
Attribute xsi:schemaLocation
see also: W3C XML Schema Recommendation "How schema definitions are located on the Web"
Implementation with slashes, no backslashes permitted
example:
<railml xmlns="http://www.railml.org/schemas/2009" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.railml.org/schemas/2009 ../schema/railML.xsd">