I am looking for a way to not have some letters in the numbering of chapters generated by xalan in an .xml to .fo transformation. I am using org.apache.xalan.xsltc.trax.TransformerFactoryImpl to transform an .xml file into an .fo file to later make a PDF out of it. In the xml file I have some numbered chapters like so :
<prcitem2 numbering="9">
They are transformed in the .fo like so : (This block is inside an fo:list-item-label, inside an fo:list-item, but I am on mobile and can't edit it properly. Sorry)
<fo:block>Й.</fo:block>
The xsl in charge of the transformation is :
<xsl:when test="ancestor-or-self::prcitem2">
<xsl:choose>
<xsl:when test="($language = 'ru')">
<xsl:number count="prcitem2" format="А."/>
</xsl:when>
</xsl:choose>
But my Russian comrades have informed me that some of their letters can't be used in numbering as it is not allowed by ATA and Russian standards (e.g. Й, З (that's not a 3) and some others). Is there a way to forbid the use of these letters ?
As I mentioned in comments, I don't see a way to "fix" the built-in xsl:number algorithm and I suggest you replace it with your own.
In the following template, replace the alpha parameter's value with the Cyrillic characters you want to use. Everything else is self-adjusting.
Note that the input numbering is expected to start at zero, so call the template with the decimal parameter's value being = "$your-number - 1".
<xsl:template name="dec-to-alpha">
<xsl:param name="decimal"/>
<xsl:param name="alpha" select="'ABCDEFGHIJKLMNOPQRSTUVWXYZ'"/>
<xsl:variable name="base" select="string-length($alpha)"/>
<xsl:variable name="bit" select="$decimal mod $base"/>
<xsl:variable name="char" select="substring($alpha, $bit + 1, 1)"/>
<xsl:variable name="next" select="floor($decimal div $base)"/>
<xsl:if test="$next">
<xsl:call-template name="dec-to-alpha">
<xsl:with-param name="decimal" select="$next - 1"/>
</xsl:call-template>
</xsl:if>
<xsl:value-of select="$char"/>
</xsl:template>