It looks like I didn't make myself very clear, sorry about that. I meant
processing atomic values, instead of processing nodes. You asked for an
example, here it goes ;)
Suppose you have this great calculator, that can add or multiply to values:
<xsl:param name="left" />
<xsl:param name="right" />
<xsl:param name="operator" />
<xsl:template name="calculator">
<xsl:choose>
<xsl:when test="$operator = '*'">
<xsl:value-of select="$left * $right" />
</xsl:when>
<xsl:when test="$operator = '+'">
<xsl:value-of select="$left + $right" />
</xsl:when>
<xsl:otherwise>Oops! Wrong operator!</xsl:otherwise>
</xsl:choose>
</xsl:template>
I don't think (but would be happy to be proven wrong) that this can be
implemented in XSLT 1.0 without xsl:choose or xsl:if. However, in XSLT
2.0 you can do this (other solutions possible):
<xsl:template name="calculator">
<xsl:variable name="operator-node">
<operator><xsl:value-of select="$operator" /></operator>
</xsl:variable>
<xsl:apply-templates select="$operator-node/operator" />
</xsl:template>
<xsl:template match="operator[text() = '*']">
<xsl:value-of select="$left * $right" />
</xsl:template>
<xsl:template match="operator[text() = '+']">
<xsl:value-of select="$left + $right" />
</xsl:template>
<xsl:template match="operator">
<xsl:text>Oops! Wrong operator!</xsl:text>
</xsl:template>
I am not 100% sure if every string or other atomic operation can be
represented by using a temporary result tree fragment, but if that is
possible (and it probably is), we can add the exslt:node-set function to
the required XSLT 1.0 instructions and indeed, we can than get rid of
xsl:if and xsl:choose.
Cheers,
Abel Braaksma
Exselt XSLT 3.0 processor
http://exselt.net
On 30-3-2014 1:07, Dimitre Novatchev wrote:
On Sat, Mar 29, 2014 at 4:13 PM, Abel Braaksma (Exselt)
<abel(_at_)exselt(_dot_)net> wrote:
I don't think you can do everything
with XSLT 1.0 that you can do now with a subset that does not include
xsl:if (xsl:choose can be implemented in xsl:ifs).
If I understand this correctly, it says that <xsl:choose> cannot be
implemented if there is no <xsl:if> instruction available.
But it can.
An <xsl:choose> with N outcomes can be expressed in XSLT 2 as a single:
<xsl:apply-templates select="my:special-node"/>
and N templates of the form:
<xsl:template match="my:special-node[condition]">
<!-- The wanted code here -->
<xsl:template>
In XSLT 1.0 we sometimes can only specify the condition within a
predicate in the "select" attribute of the <xsl:apply-templates>
instruction.
Thus, an <xsl:choose> with N outcomes can be implemented using N
<xsl:apply-templates> instructions of the form:
<xsl:apply-templates select="my:special-node[conditionK]"/>
and N templates -- exactly as in the case for XSLT 2.0 above.
This is the full proof that XSLT conditional instructions can be
eliminated in any version of XSLT.
BTW, I have quite a lot of experience writing complex transformations
without any XSLT conditional instructions. :)
Cheers,
Dimitre Novatchev
--~------------------------------------------------------------------
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
To unsubscribe, go to: http://lists.mulberrytech.com/xsl-list/
or e-mail:
<mailto:xsl-list-unsubscribe(_at_)lists(_dot_)mulberrytech(_dot_)com>
--~--
--~------------------------------------------------------------------
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
To unsubscribe, go to: http://lists.mulberrytech.com/xsl-list/
or e-mail: <mailto:xsl-list-unsubscribe(_at_)lists(_dot_)mulberrytech(_dot_)com>
--~--