One-liner to assign a variable one of two values, dependent on condition (XSLT 1.0, that is)

one-line-toggle.xslt

<!-- Selects 'YES' if CONDITION is true() -->
<xsl:value-of select="substring('YES|NO', not(CONDITION) * 4 + 1, 3)" />

<!-- Selects 'NO' if CONDITION is true() -->
<xsl:value-of select="substring('YES|NO', boolean(CONDITION) * 4 + 1, 3)" />

<!--
Notes:

   * Need both versions because the longer value must be the first of the two
   * 4 is the index of the pipe (|) character (or the string-length of the first value plus one)
   * 3 is the string-length of the first value

Credit goes to Jeni Tennison - I saw this used a couple of times in her excellent book "XSLT and XPath on the Edge".
 
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