Replace multiple characters in a single element using XSLT - xslt

Question

I am in need to find and replace a entities and characters to strings. For example,   should be replaced by ' ' empty space, $ should be replaced by |doll|, % should be replaced by |perc|. I can use XSLT 1.0.
XML document:
<?xml version="1.0"?>
<chapter>
<math>
<mtext>This is $400, 300%to500%.</mtext>
</math>
</chapter>
XSLT 1.0 transformation tried:
<?xml version='1.0'?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="mtext">
<mtext>
<xsl:choose>
<xsl:when test="contains(.,' ') or contains(.,'$') or contains(.,'%')">
<xsl:if test="contains(.,' ')"><xsl:call-template name="replace-string"><xsl:with-param name="text" select="."/><xsl:with-param name="from"> </xsl:with-param><xsl:with-param name="to" select="' '"/></xsl:call-template><xsl:variable name="mtext_text" select="."/></xsl:if>
<xsl:variable name="mtext_text" select="."/>
<xsl:if test="contains(.,'$')"><xsl:call-template name="replace-string"><xsl:with-param name="text" select="mtext_text"/><xsl:with-param name="from">$</xsl:with-param><xsl:with-param name="to" select="'|doll|'"/></xsl:call-template><xsl:variable name="mtext_text" select="."/></xsl:if>
<xsl:variable name="mtext_text" select="."/>
<xsl:if test="contains(.,'%')"><xsl:call-template name="replace-string"><xsl:with-param name="text" select="mtext_text"/><xsl:with-param name="from">%</xsl:with-param><xsl:with-param name="to" select="'|perc|'"/></xsl:call-template></xsl:if>
</xsl:when>
<xsl:otherwise>
<xsl:apply-templates/>
</xsl:otherwise>
</xsl:choose>
</mtext>
</xsl:template>
<xsl:template name="replace-string">
<xsl:param name="text"/>
<xsl:param name="from"/>
<xsl:param name="to"/>
<xsl:choose>
<xsl:when test="contains($text, $from)">
<xsl:variable name="before" select="substring-before($text, $from)"/>
<xsl:variable name="after" select="substring-after($text, $from)"/>
<xsl:variable name="prefix" select="concat($before, $to)"/>
<xsl:copy-of select="$before"/>
<xsl:value-of select="$to" disable-output-escaping="yes"/>
<xsl:call-template name="replace-string">
<xsl:with-param name="text" select="$after"/>
<xsl:with-param name="from" select="$from"/>
<xsl:with-param name="to" select="$to"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:copy-of select="$text"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
Required output:
<?xml version='1.0' ?>
<mtext>This is |doll|400, 300|perc|to500|perc|.</mtext>

Answer 1

This XSLT 1.0 transformation:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:my="my:my" extension-element-prefixes="xsl">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<my:reps>
<rep>
<old> </old>
<new xml:space="preserve"> </new>
</rep>
<rep>
<old>$</old>
<new>|doll|</new>
</rep>
<rep>
<old>%</old>
<new>|perc|</new>
</rep>
</my:reps>
<xsl:variable name="vReps" select="document('')/*/my:reps/*"/>
<xsl:template match="mtext">
<xsl:copy>
<xsl:call-template name="multiReplace"/>
</xsl:copy>
</xsl:template>
<xsl:template name="multiReplace">
<xsl:param name="pText" select="."/>
<xsl:param name="pRep" select="$vReps[1]"/>
<xsl:choose>
<xsl:when test="not($pRep)"><xsl:value-of select="$pText"/></xsl:when>
<xsl:otherwise>
<xsl:variable name="vReplaced">
<xsl:call-template name="replace">
<xsl:with-param name="pText" select="$pText"/>
<xsl:with-param name="pOld" select="$pRep/old"/>
<xsl:with-param name="pNew" select="$pRep/new"/>
</xsl:call-template>
</xsl:variable>
<xsl:call-template name="multiReplace">
<xsl:with-param name="pText" select="$vReplaced"/>
<xsl:with-param name="pRep" select="$pRep/following-sibling::*[1]"/>
</xsl:call-template>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
<xsl:template name="replace">
<xsl:param name="pText"/>
<xsl:param name="pOld"/>
<xsl:param name="pNew"/>
<xsl:if test="$pText">
<xsl:value-of select="substring-before(concat($pText,$pOld), $pOld)"/>
<xsl:if test="contains($pText, $pOld)">
<xsl:value-of select="$pNew"/>
<xsl:call-template name="replace">
<xsl:with-param name="pText" select="substring-after($pText, $pOld)"/>
<xsl:with-param name="pOld" select="$pOld"/>
<xsl:with-param name="pNew" select="$pNew"/>
</xsl:call-template>
</xsl:if>
</xsl:if>
</xsl:template>
</xsl:stylesheet>
when applied on the provided XML document:
<chapter>
<math>
<mtext>This is $400, 300%to500%.</mtext>
</math>
</chapter>
produces the wanted, correct result:
<mtext>This is |doll|400, 300|perc|to500|perc|.</mtext>