How can I trim space in XSLT without replacing repating whitespaces by single ones?

Question

The function normalize-space replaces sequences of whitespaces by a single space and trims the provided string. How can I only trim the string without the replacement of whitespaces? There are proprietary solutions like orcl:left-trim, but I am looking for a non-proprietary one.

Example:

<xsl:value-of select="trim(/Car/Description)"/>

should turn

<car>
  <description>  To get more information look at:     www.example.com </description>
</car>

into

"To get more information look at:     www.example.com"

Answer 1

A solution using just xslt 1.0 templates:

<xsl:variable name="whitespace" select="'&#09;&#10;&#13; '" />

<!-- Strips trailing whitespace characters from 'string' -->
<xsl:template name="string-rtrim">
    <xsl:param name="string" />
    <xsl:param name="trim" select="$whitespace" />

    <xsl:variable name="length" select="string-length($string)" />

    <xsl:if test="$length &gt; 0">
        <xsl:choose>
            <xsl:when test="contains($trim, substring($string, $length, 1))">
                <xsl:call-template name="string-rtrim">
                    <xsl:with-param name="string" select="substring($string, 1, $length - 1)" />
                    <xsl:with-param name="trim"   select="$trim" />
                </xsl:call-template>
            </xsl:when>
            <xsl:otherwise>
                <xsl:value-of select="$string" />
            </xsl:otherwise>
        </xsl:choose>
    </xsl:if>
</xsl:template>

<!-- Strips leading whitespace characters from 'string' -->
<xsl:template name="string-ltrim">
    <xsl:param name="string" />
    <xsl:param name="trim" select="$whitespace" />

    <xsl:if test="string-length($string) &gt; 0">
        <xsl:choose>
            <xsl:when test="contains($trim, substring($string, 1, 1))">
                <xsl:call-template name="string-ltrim">
                    <xsl:with-param name="string" select="substring($string, 2)" />
                    <xsl:with-param name="trim"   select="$trim" />
                </xsl:call-template>
            </xsl:when>
            <xsl:otherwise>
                <xsl:value-of select="$string" />
            </xsl:otherwise>
        </xsl:choose>
    </xsl:if>
</xsl:template>

<!-- Strips leading and trailing whitespace characters from 'string' -->
<xsl:template name="string-trim">
    <xsl:param name="string" />
    <xsl:param name="trim" select="$whitespace" />
    <xsl:call-template name="string-rtrim">
        <xsl:with-param name="string">
            <xsl:call-template name="string-ltrim">
                <xsl:with-param name="string" select="$string" />
                <xsl:with-param name="trim"   select="$trim" />
            </xsl:call-template>
        </xsl:with-param>
        <xsl:with-param name="trim"   select="$trim" />
    </xsl:call-template>
</xsl:template>

Test code:

<ltrim>
    <xsl:call-template name="string-ltrim">
        <xsl:with-param name="string" select="'   &#10;   test  '" />
    </xsl:call-template>
</ltrim>
<rtrim>
    <xsl:call-template name="string-rtrim">
        <xsl:with-param name="string" select="'    &#10;    test  &#10;  '" />
    </xsl:call-template>
</rtrim>
<trim>
    <xsl:call-template name="string-trim">
        <xsl:with-param name="string" select="'    &#10;    test  &#10;  '" />
    </xsl:call-template>
</trim>

Output:

<test>
    <ltrim>test  </ltrim>
    <rtrim>   
    test</rtrim>
    <trim>test</trim>
</test>