{{sane|expr}} at the point in the markup where a known value is needed.

The output is

  • {{sane}} : @@absent@@
  • {{sane|}} : @@empty@@
  • {{sane|1=}} : @@empty@@
  • {{sane|1=value}} : value
  • {{sane|value}} : value

This template was created due to apparent limitations in how media-wiki handles "blank" vs null parameters passed as a template parameter.

The template forces a "known" value of @@empty@@ where a parameter is blank or empty.