Specify output format of xslt - xslt

Question

I know this is asked before but I can't find a simple example. Just trying to change output format. My existing XSLT is this and works but output format is always .txt.
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:text>*,</xsl:text>
<xsl:value-of select="//AccountFields/AccountID"/>
<xsl:text>
</xsl:text>
<xsl:for-each select="//TransactionLine">
<xsl:variable name="i" select="position()" />
<xsl:value-of select="//AccountFields/AccountID"/>
<xsl:text>,</xsl:text>
<xsl:value-of select="ItemFields/ItemID"/>
<xsl:text>,</xsl:text>
<xsl:value-of select="TransactionLineFields/UnitQuantity"/>
<xsl:text>,</xsl:text>
<xsl:value-of select="TransactionLineFields/UnitPrice"/>
<xsl:text>
</xsl:text>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
I tried adding <xsl:result-document href="Order.csv" method="text"> but the file fails to generate completely and the tool I'm using doesn't give me a clear way to see errors.
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:result-document href="Order.csv" method="text">
<xsl:text>*,</xsl:text>
<xsl:value-of select="//AccountFields/AccountID"/>
<xsl:text>
</xsl:text>
<xsl:for-each select="//TransactionLine">
<xsl:variable name="i" select="position()" />
<xsl:value-of select="//AccountFields/AccountID"/>
<xsl:text>,</xsl:text>
<xsl:value-of select="ItemFields/ItemID"/>
<xsl:text>,</xsl:text>
<xsl:value-of select="TransactionLineFields/UnitQuantity"/>
<xsl:text>,</xsl:text>
<xsl:value-of select="TransactionLineFields/UnitPrice"/>
<xsl:text>
</xsl:text>
</xsl:for-each>
</xsl:result-element>
</xsl:template>
</xsl:stylesheet>

Answer 1

xsl:result-document is only available in XSLT 2.0 and later versions.
If you can use XSLT-2.0, you could pass parameters and set the method attribute with an attribute value template to
"xml" | "html" | "xhtml" | "text" | "json" | "adaptive" | eqname
Here, the file extension and the output method are set dynamically by parameters passed to the stylesheet:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:param name="fileExt" select="'.csv'" />
<xsl:param name="fileMethod" select="'xml'" />
<xsl:template match="/">
<xsl:result-document href="{concat('Order',$fileExt)}" method="{$fileMethod}">
<xsl:text>*,</xsl:text>
...
</xsl:result-document>
</xsl:template>
</xsl:stylesheet>
It has been tested with Saxon.
If you wanted to change the xsl:output method instead, have a look at this question.