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Hi Folks, Yesterday’s responses were outstanding and illuminating. Thank you. I learned that a declarative program describes the relationship of the output to the input. This raises new questions. Let’s take an example. Suppose that this is the input: <XML-file>http://www.example.org/book.xml</XML-file> I want the output to contain the URL and the filename separated: <XML-file> <URL>http://www.example.org/</URL> <Filename>book.xml</Filename> </XML-file> This XSLT code describes the relationship of the output to the input: <xsl:template match="XML-file"> <xsl:variable name="url" select="f:substring-before-last(., '/')" /> <XML-file> <URL> <xsl:value-of select="$url" /> </URL> <Filename> <xsl:value-of select="substring-after(., $url)" /> </Filename> </XML-file> </xsl:template> I believe this code is declarative. Do you agree? Note my use of the function, f:substring-before-last(). There is no such built-in function, I created it. Below is how I implemented it. The implementation doesn’t seem descriptive. It seems quite recipe-like:
Get the substring before $delimiter and output it, then output $delimiter, and then recurse.
It seems quite imperative. Do you agree? If I stuff a bunch of imperative code into functions, and the “main” code is declarative, do I still have a declarative program? Here’s my implementation of f:substring-before-last(): <xsl:function name="f:substring-before-last" as="xs:string?"> <xsl:param name="string" as="xs:string" /> <xsl:param name="delimiter" as="xs:string" /> <xsl:if test="contains( $string, $delimiter )"> <xsl:variable name="url"> <xsl:value-of select="substring-before( $string, $delimiter )"/> <xsl:value-of select="$delimiter"/> <xsl:value-of select="f:substring-before-last(substring-after ( $string, $delimiter ), $delimiter)" /> </xsl:variable> <xsl:value-of select="$url" /> </xsl:if> </xsl:function> |