r example, the format "%{-size,pixelsize{sub-expr}}" will expand "sub-expr"
with <TT
CLASS="PARAMETER"
><I
>pattern</I
></TT
> sans the size and pixelsize elements.&#13;</P
><P
>&#13;A <I
CLASS="FIRSTTERM"
>filter-in</I
> tag
is one starting with the character "+" followed by a
comma-separated list of element names, followed by a sub-expression enclosed
in curly braces.  The sub-expression will be expanded but with a pattern that
only has the listed elements from the surrounding pattern.
For example, the fo