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Re: Detecting unbound options

From: Norman Walsh <ndw@nwalsh.com>
Date: Thu, 28 May 2009 08:42:06 -0400
To: XProc Dev <xproc-dev@w3.org>
Message-ID: <m2y6shbdr5.fsf@nwalsh.com>
"Toman_Vojtech@emc.com" <Toman_Vojtech@emc.com> writes:
>> A small win, but a win !
[...]
> With choose, you don't have this problem.

True. Here, FWIW, is what the pipeline looks like if we add a
p:option-available function that takes a single QName and returns true
if and only if an option with that name exists and has a value.

<p:declare-step xmlns:p="http://www.w3.org/ns/xproc"
                xmlns:c="http://www.w3.org/ns/xproc-step"
                xmlns:pxp="http://exproc.org/proposed/steps"
                type="pxp:recursive-directory-list">
<p:output port="result"/>
<p:option name="path" required="true"/>
<p:option name="depth" select="0"/>
<p:option name="include-filter"/>
<p:option name="exclude-filter"/>

<p:choose>
  <p:xpath-context>
    <p:empty/>
  </p:xpath-context>
  <p:when test="p:option-available('include-filter')
                and p:option-available('exclude-filter')">
    <p:directory-list>
      <p:with-option name="path" select="$path">
        <p:empty/>
      </p:with-option>
      <p:with-option name="include-filter" select="$include-filter">
        <p:empty/>
      </p:with-option>
      <p:with-option name="exclude-filter" select="$exclude-filter">
        <p:empty/>
      </p:with-option>
    </p:directory-list>
  </p:when>
  <p:when test="p:option-available('exclude-filter')">
    <p:directory-list>
      <p:with-option name="path" select="$path">
	<p:empty/>
      </p:with-option>
      <p:with-option name="exclude-filter" select="$exclude-filter">
	<p:empty/>
      </p:with-option>
    </p:directory-list>
  </p:when>
  <p:when test="p:option-available('include-filter')">
    <p:directory-list>
      <p:with-option name="path" select="$path">
	<p:empty/>
      </p:with-option>
      <p:with-option name="include-filter" select="$include-filter">
	<p:empty/>
      </p:with-option>
    </p:directory-list>
  </p:when>
  <p:otherwise>
    <p:directory-list>
      <p:with-option name="path" select="$path">
	<p:empty/>
      </p:with-option>
    </p:directory-list>
  </p:otherwise>
</p:choose>

<p:viewport match="c:directory[parent::*]">
  <p:choose>
    <p:when test="$depth != 0 and p:option-available('include-filter')
                  and p:option-available('exclude-filter')">
      <pxp:recursive-directory-list>
	<p:with-option name="path" select="concat($path,'/',/c:directory/@name)"/>
	<p:with-option name="depth" select="$depth - 1">
	  <p:empty/>
	</p:with-option>
	<p:with-option name="include-filter" select="$include-filter">
	  <p:empty/>
	</p:with-option>
	<p:with-option name="exclude-filter" select="$exclude-filter">
	  <p:empty/>
	</p:with-option>
      </pxp:recursive-directory-list>
    </p:when>
    <p:when test="$depth != 0 and p:option-available('exclude-filter')">
      <pxp:recursive-directory-list>
	<p:with-option name="path" select="concat($path,'/',/c:directory/@name)"/>
	<p:with-option name="depth" select="$depth - 1">
	  <p:empty/>
	</p:with-option>
	<p:with-option name="exclude-filter" select="$exclude-filter">
	  <p:empty/>
	</p:with-option>
      </pxp:recursive-directory-list>
    </p:when>
    <p:when test="$depth != 0 and p:option-available('include-filter')">
      <pxp:recursive-directory-list>
	<p:with-option name="path" select="concat($path,'/',/c:directory/@name)"/>
	<p:with-option name="depth" select="$depth - 1">
	  <p:empty/>
	</p:with-option>
	<p:with-option name="include-filter" select="$include-filter">
	  <p:empty/>
	</p:with-option>
      </pxp:recursive-directory-list>
    </p:when>
    <p:when test="$depth != 0">
      <pxp:recursive-directory-list>
	<p:with-option name="path" select="concat($path,'/',/c:directory/@name)"/>
	<p:with-option name="depth" select="$depth - 1">
	  <p:empty/>
	</p:with-option>
      </pxp:recursive-directory-list>
    </p:when>
    <p:otherwise>
      <p:identity/>
    </p:otherwise>
  </p:choose>
</p:viewport>

</p:declare-step>


                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | Talk as if you were making your will:
http://nwalsh.com/            | the fewer the words the less the
                              | litigation.-- Gracián

Received on Thursday, 28 May 2009 12:42:49 GMT

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