Question

I have a few strings containing a variant of Hexadecimal strings (source is framemaker if one would care). Strings could therefore look like

this is some sentence with some hex code\x27 s , and we need that
fixed.

and will need to be changed to

this is some sentence with some hex code’s , and we need that fixed.

In reality there can be a few of these in a single string, so I’m looking on the best way to walk through the text, capture all hex codes (looking like \x## ) and replace all of these codes with the correct character. I have made a xml list / lookup table containing all the characters as follows :

<xsl:param name="reflist">
    <Code Value="\x27">'</Code>
<Code Value="\x28">(</Code>
<Code Value="\x29">)</Code>
<Code Value="\x2a">*</Code>
<Code Value="\x2b">+</Code>
    <!-- much more like these... -->
</xsl:param>

For now I used a simple replace argument but there are simply too many characters to make this workable.

What’s the best way to do this?

Answer 1

Use analyze-string as in

<xsl:template match="text()">
  <xsl:analyze-string select="." regex="\\x[0-9a-f]{{2}}" flags="i">
    <xsl:matching-substring>
      <xsl:value-of select="$reflist/Code[@Value = .]"/>
    </xsl:matching-substring>
    <xsl:non-matching-substring>
      <xsl:value-of select="."/>
    </xsl:non-matching-substring>
  </xsl:analyze-string>
</xsl:template>

I would also suggest to use a key e.g.

<xsl:param name="reflist" as="document-node()">
  <xsl:document>
    <Root>
      <Code Value="\x27">'</Code>
      <Code Value="\x28">(</Code>
      <Code Value="\x29">)</Code>
      <Code Value="\x2a">*</Code>
      <Code Value="\x2b">+</Code>
      <!-- much more like these... -->
    </Root>
  </xsl:document>
</xsl:param>

<xsl:key name="code-by-value" match="Code" use="@Value"/>

then the lookup can be improved to

<xsl:template match="text/text()">
  <xsl:analyze-string select="." regex="\\x[0-9a-f]{{2}}" flags="i">
    <xsl:matching-substring>
      <xsl:value-of select="key('code-by-value', ., $reflist)"/>
    </xsl:matching-substring>
    <xsl:non-matching-substring>
      <xsl:value-of select="."/>
    </xsl:non-matching-substring>
  </xsl:analyze-string>
</xsl:template>

I have found some time to morph the suggestions made into working code, with the input being

<root>
  <text>this is some sentence with some hex code\x27 s , and we need that \x28and this\x29 fixed.</text>
</root>

and the complete stylesheet being

<xsl:stylesheet 
  version="2.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:xs="http://www.w3.org/2001/XMLSchema"
  exclude-result-prefixes="xs">

<xsl:param name="reflist" as="document-node()">
  <xsl:document>
    <Root>
      <Code Value="\x27">'</Code>
      <Code Value="\x28">(</Code>
      <Code Value="\x29">)</Code>
      <Code Value="\x2a">*</Code>
      <Code Value="\x2b">+</Code>
      <!-- much more like these... -->
    </Root>
  </xsl:document>
</xsl:param>

<xsl:key name="code-by-value" match="Code" use="@Value"/>

<xsl:template match="@* | node()">
  <xsl:copy>
    <xsl:apply-templates select="@* , node()"/>
  </xsl:copy>
</xsl:template>

<xsl:template match="text/text()">
  <xsl:analyze-string select="." regex="\\x[0-9a-f]{{2}}" flags="i">
    <xsl:matching-substring>
      <xsl:value-of select="key('code-by-value', ., $reflist)"/>
    </xsl:matching-substring>
    <xsl:non-matching-substring>
      <xsl:value-of select="."/>
    </xsl:non-matching-substring>
  </xsl:analyze-string>
</xsl:template>

</xsl:stylesheet>

Saxon 9.4 transforms the input as follows:

<root>
  <text>this is some sentence with some hex code' s , and we need that (and this) fixed.</text>
</root>