The directives of the 'expp' tool

NOTA : xpp is the namespace used by default, but you can change it with the -n, --namespace option.

• <xpp:define name=“NAME”>…</xpp:define> : definition of a macro named NAME.
• <xpp:expand select=“NAME”>…</xpp:expand> : expansion of the macro named NAME.
• <UserTag xpp:attribute=“ATTRIBUTE_NAME,MACRO_NAME”>…</UserTag> : expansion of the macro named MACRO_NAME as value of an attribute named ATTRIBUTE_NAME.
• <xpp:expand href=“FILENAME”/> : inclusion of the content of the file named FILENAME.
• <xpp:set name=“NAME” value=“VALUE”/> : set the variable named NAME to the value VALUE.
• <xpp:ifeq select=“NAME” value=“VALUE”>…</xpp:ifeq> : the content of this directive is skipped unless variable named NAME has VALUE as value.
• <xpp:bloc>…</xpp:bloc> : this directive has no effect by itself, but is required under some circumstances by above directives.

This directive allows to define a macro. The body of a macro must contain one and only one root tag (use bloc directive if needed) ; it can not be empty (nor <xpp:define name=”...”></xpp:define> nor <xpp:define name=”...”/>). The body of a macro, when enclosed in a bloc directive, can contain several child tags.

The content of a macro is expanded using the expand directive with select attribute.

<xpp:define name="NAME">
Body
</xpp:define>

Defines a macro named NAME with content Body.

<xpp:expand select="NAME"/>

Expands the content of the macro named NAME (the entire directive is replaced by Body as defined above).

The expand directive with select attribute allows to expand a macro previously defined by a define directive.

<xpp:define name="NAME">
Body
</xpp:define>

Defines a macro named NAME with content Body.

<xpp:expand select="NAME"/>

Expands the content of the macro named NAME (the entire directive is remplaced by Body as defined above).

The expand directive with href attribute allows to include a file. The included file must contain one and only one root tag (use bloc directive if needed). If the file location is relative, the base directory is the one of the file which contains the given expand directive.

<xpp:expand href="FILENAME"/>

The whole expand directive is replaced by the content of the file named FILENAME.

The attribute directive allows to create an attribute with the content of a macro previously defined by a define directive as value. Unlike the other directives, which are all used as a tag, the attribute directive must be used as an attribute.

The body of the macro must expand to a value, as it will be used as an attribute value. It can contain other xpp directives, but once there are all handled, the result must be a value, with no tag.

NOTA : this feature is experimental, but seems so long reliable.

<xpp:define name="MACRO_NAME">VALUE</xpp:define>

Defines a macro named MACRO_NAME with content VALUE.

<UserTag xpp:attribute="ATTRIBUTE_NAME,MACRO_NAME"/>

Creates an attribute named ATTRIBUTE_NAME with the content of the macro named MACRO_NAME as value.

The set directive allows to affect a value to a variable. The value of a variable can be tested with the ifeq directive.

<xpp:set name="VARIABLE" value="VALUE"/>

Sets the variables named NAME with the value VALUE.

The ifeq directive allows to test the value of a variables defined by the set directive, and, depending of the result of this test, to skip or not the content of the given ifeq directive.

<xpp:ifeq select="VARIABLE" value="VALUE">
BODY
</xpp:ifeq>

The variable named VARIABLE is tested. If VARIABLE was set to VALUE by a set directive, then BODY is handled, otherwise BODY is skipped. Even if BODY is skipped, it must be a valid xml tree (i.e. must contain one and only one root tag ; use bloc directive if needed).

The content of the define and ifeq directives, and also the content of a file included by the expand directive (with href attribute), must be a valid XML tree, i.e. it must contain one, and only one, root tag (with possibly child tags).

In the resulting file, opening and closing bloc directives do not appear.

Case where a content is only a value (without enclosing tag) :

<xpp:bloc>/home/dupont/</xpp:bloc>

Case where the content is constituted by more then one root tags :

<xpp:bloc>
	<Name>
		<Last>Doe</Last>
		<First>John</First>
	</Name>
	<EMail>doe@site.com<</EMail>
</xpp:bloc>

File common.xcf :

<?xml version="1.0" encoding="ISO-8859-1"?>
<xpp:bloc xmlns:xpp="http://zeusw.org/epeios/xpp">
	<xpp:define name="LinuxURL">
		<xpp:bloc>linux.org</xpp:bloc>
	</xpp:define>
	<xpp:define name="WindowsURL">
		<xpp:bloc>windows.com</xpp:bloc>
	</xpp:define>
	<xpp:define name="Linux">
		<xpp:bloc>
			<xpp:define name="Directory">
				<xpp:bloc>/home/dupond/</xpp:bloc>
			</xpp:define>
			<xpp:define name="RootURL">
				<xpp:expand select="LinuxURL"/>
			</xpp:define>
		</xpp:bloc>
	</xpp:define>
	<xpp:define name="Windows">
		<xpp:bloc>
			<xpp:define name="Directory">
				<xpp:bloc>c:\Documents\Dupond\</xpp:bloc>
			</xpp:define>
			<xpp:define name="RootURL">
				<xpp:expand select="WindowsURL"/>
			</xpp:define>
		</xpp:bloc>
	</xpp:define>
	<xpp:define name="File">
		<xpp:bloc>
			<xpp:expand select="Directory"/>
			<xpp:expand select="FileName"/>
		</xpp:bloc>
	</xpp:define>
	<xpp:ifeq select="OS" value="Linux">
		<xpp:expand select="Linux"/>
	</xpp:ifeq>
	<xpp:ifeq select="OS" value="Windows">
		<xpp:expand select="Windows"/>
	</xpp:ifeq>
	<SomeFile>
		<xpp:define name="FileName">
			<xpp:bloc>SomeFile</xpp:bloc>
		</xpp:define>
		<xpp:expand select="File"/>
	</SomeFile>
	<OtherFile>
		<xpp:define name="FileName">
			<xpp:bloc>OtherFile</xpp:bloc>
		</xpp:define>
		<xpp:expand select="File"/>
	</OtherFile>
	<SomeURL>
		<xpp:bloc>http://</xpp:bloc>
		<xpp:expand select="RootURL"/>
		<xpp:bloc>/something</xpp:bloc>
	</SomeURL>
</xpp:bloc>

File linux.xcf :

<?xml version="1.0" encoding="ISO-8859-1"?>
<Configuration xmlns:xpp="http://zeusw.org/epeios/xpp">
	<xpp:set name="OS" value="Linux"/>
	<xpp:expand href="common.xcf"/>
</Configuration>

File windows.xcf :

<?xml version="1.0" encoding="ISO-8859-1"?>
<Configuration xmlns:xpp="http://zeusw.org/epeios/xpp">
	<xpp:set name="OS" value="Windows"/>
	<xpp:expand href="common.xcf"/>
</Configuration>

By launching

expp linux.xcf

you obtain following result :

<?xml version="1.0" encoding="ISO-8859-1"?>
<Configuration>
	<SomeFile>/home/dupond/SomeFile</SomeFile>
	<OtherFile>/home/dupond/OtherFile</OtherFile>
	<SomeURL>http://linux.org/something</SomeURL>
</Configuration>

By launching

expp windows.xcf

you obtain following result :

<?xml version="1.0" encoding="ISO-8859-1"?>
<Configuration>
	<SomeFile>c:\Documents\Dupond\SomeFile</SomeFile>
	<OtherFile>c:\Documents\Dupond\OtherFile</OtherFile>
	<SomeURL>http://windows.com/something</SomeURL>
</Configuration>