Producing a new line in XSLT

Question

The following XSL code will produce a newline (line feed) character:

<xsl:text>&#xa;</xsl:text>

For a carriage return, use:

<xsl:text>&#xd;</xsl:text>

My favoured method for doing this looks something like:

<xsl:stylesheet>

<xsl:output method='text'/>

<xsl:variable name='newline'><xsl:text>
</xsl:text></xsl:variable>

<!-- note that the layout there is deliberate -->

...

</xsl:stylesheet>

Then, whenever you want to output a newline (perhaps in csv) you can output something like the following:

<xsl:value-of select="concat(elem1,elem2,elem3,$newline)" />

I've used this technique when outputting sql from xml input. In fact, I tend to create variables for commas, quotes and newlines.

Include the attribute Method="text" on the xsl:output tag and include newlines in your literal content in the XSL at the appropriate points. If you prefer to keep the source code of your XSL tidy use the entity 
 where you want a new line.

You can use: <xsl:text>&#10;</xsl:text>

see the example

<xsl:variable name="module-info">
  <xsl:value-of select="@name" /> = <xsl:value-of select="@rev" />
  <xsl:text>&#10;</xsl:text>
</xsl:variable>

if you write this in file e.g.

<redirect:write file="temp.prop" append="true">
  <xsl:value-of select="$module-info" />
</redirect:write>

this variable will produce a new line infile as:

commons-dbcp_commons-dbcp = 1.2.2
junit_junit = 4.4
org.easymock_easymock = 2.4

IMHO no more info than @Florjon gave is needed. Maybe some small details are left to understand why it might not work for us sometimes.

First of all, the &#xa (hex) or &#10 (dec) inside a <xsl:text/> will always work, but you may not see it.

1. There is no newline in a HTML markup. Using a simple <br/> will do fine. Otherwise you'll see a white space. Viewing the source from the browser will tell you what really happened. However, there are cases you expect this behaviour, especially if the consumer is not directly a browser. For instance, you want to create an HTML page and view its structure formatted nicely with empty lines and idents before serving it to the browser.
2. Remember where you need to use disable-output-escaping and where you don't. Take the following example where I had to create an xml from another and declare its DTD from a stylesheet.

The first version does escape the characters (default for xsl:text)

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
    <xsl:output method="xml" indent="yes" encoding="utf-8"/>

    <xsl:template match="/">
        <xsl:text>&lt;!DOCTYPE Subscriptions SYSTEM "Subscriptions.dtd"&gt;&#xa;&#xa;&#xd;</xsl:text>
        <xsl:copy>
            <xsl:apply-templates select="*" mode="copy"/>
        </xsl:copy>
    </xsl:template>
    <xsl:template match="@*|node()" mode="copy">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()" mode="copy"/>
        </xsl:copy>
    </xsl:template>

</xsl:stylesheet>

and here is the result:

<?xml version="1.0" encoding="utf-8"?>
&lt;!DOCTYPE Subscriptions SYSTEM "Subscriptions.dtd"&gt;

&#13;<Subscriptions>
    <User id="1"/>   
</Subscriptions>

Ok, it does what we expect, escaping is done so that the characters we used are displayed properly. The XML part formatting inside the root node is handled by ident="yes". But with a closer look we see that the newline character &#xa was not escaped and translated as is, performing a double linefeed! I don't have an explanation on this, will be good to know. Anyone?

The second version does not escape the characters so they're producing what they're meant for. The change made was:

<xsl:text disable-output-escaping="yes">&lt;!DOCTYPE Subscriptions SYSTEM "Subscriptions.dtd"&gt;&#xa;&#xa;&#xd;</xsl:text>

and here is the result:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE Subscriptions SYSTEM "Subscriptions.dtd">

<Subscriptions>
    <User id="1"/>   
</Subscriptions>

and that will be ok. Both cr and lf are properly rendered.

3. Don't forget we're talking about nl, not crlf (nl=lf). My first attempt was to use only cr:&#xd and while the output xml was validated by DOM properly.

I was viewing a corrupted xml:

<?xml version="1.0" encoding="utf-8"?>
<Subscriptions>riptions SYSTEM "Subscriptions.dtd">
    <User id="1"/>   
</Subscriptions>

DOM parser disregarded control characters but the rendered didn't. I spent quite some time bumping my head before I realised how silly I was not seeing this!

For the record, I do use a variable inside the body with both CRLF just to be 100% sure it will work everywhere.