c1map: Add lvm:when

This allows for conditional nodes where lvm:if is not appropriate or cannot be
used.

src/current/c1map.xsl

@@ -338,8 +338,27 @@
   mode="lvmp:c1-node-result" priority="5">
 
   <lvmp:for-each name="{@lvm:for-each}">
-    <!-- proceed with processing as normal -->
-    <xsl:apply-templates select="@*|*" />
+    <xsl:choose>
+      <xsl:when test="lvm:when">
+        <lvmp:condition when="true">
+          <lvmp:when>
+            <xsl:call-template name="lvmp:gen-val">
+              <xsl:with-param name="name" select="lvm:when/@name" />
+            </xsl:call-template>
+          </lvmp:when>
+          <lvmp:cmp>
+            <xsl:apply-templates mode="lvm:valparse"
+                                 select="lvm:when/@eq" />
+          </lvmp:cmp>
+
+          <xsl:apply-templates select="@*|*" />
+        </lvmp:condition>
+      </xsl:when>
+
+      <xsl:otherwise>
+        <xsl:apply-templates select="@*|*" />
+      </xsl:otherwise>
+    </xsl:choose>
   </lvmp:for-each>
 </xsl:template>
 
@@ -366,6 +385,11 @@
 </xsl:template>
 
 
+<xsl:template match="lvm:when" priority="4">
+  <!-- handled as part of @lvm:for-each -->
+</xsl:template>
+
+
 <!--
   Unhandled node character data
 

src/current/c1map/render.xsl

@@ -291,6 +291,25 @@
 </xsl:template>
 
 
+<xsl:template match="lvmp:for-each[ lvmp:condition[ @when ] ]" mode="lvmp:render" priority="8">
+  <xsl:variable name="from">
+    <xsl:call-template name="lvmp:var-from">
+      <xsl:with-param name="name" select="@name" />
+    </xsl:call-template>
+  </xsl:variable>
+
+  <xsl:text>$contract->iterateValues( '</xsl:text>
+  <xsl:value-of select="$from" />
+  <xsl:text>', </xsl:text>
+  <xsl:text>function( $contract ) {</xsl:text>
+  <xsl:text>  return </xsl:text>
+  <xsl:apply-templates mode="lvmp:render" select="lvmp:condition" />
+  <xsl:text>;</xsl:text>
+  <xsl:text>}</xsl:text>
+  <xsl:text>)</xsl:text>
+</xsl:template>
+
+
 <!--
   The C1 import system recognizes the following formats:
 
@@ -353,6 +372,26 @@
 </xsl:template>
 
 
+
+<xsl:template mode="lvmp:render" priority="8" match="lvmp:condition[ @when ]">
+  <xsl:variable name="cond" select="." />
+
+  <xsl:text>( ( </xsl:text>
+  <xsl:text>$contract->isTruthy( </xsl:text>
+  <xsl:apply-templates select="$cond/lvmp:when/lvmp:*" mode="lvmp:render" />
+  <xsl:if test="$cond/lvmp:cmp/*">
+    <xsl:text>,</xsl:text>
+    <xsl:apply-templates select="$cond/lvmp:cmp/lvmp:*" mode="lvmp:render" />
+  </xsl:if>
+  <xsl:text>)</xsl:text>
+  <xsl:text> ) ? array(</xsl:text>
+  <xsl:apply-templates mode="lvmp:render">
+    <xsl:with-param name="no-trailing-sep" select="true()" />
+  </xsl:apply-templates>
+  <xsl:text>) : null )</xsl:text>
+</xsl:template>
+
+
 <xsl:template match="*" mode="lvmp:render" priority="1">
   <xsl:message terminate="yes">
     <xsl:text>[c1map] fatal: unexpected node during render: </xsl:text>