%modifier?  _

The format item for the space character.

With no modifiers, the "%_" format item has the same effect as a space character. However, this format item permits the "s" modifier which indicates that white-space stripping can be applied to this space.

Normally, space characters in an output action are intended to appear in the final OmniMark output. Use of the "s" modifier allows the programmer to avoid strings of white space characters that would otherwise be generated if successive output actions (perhaps from different parts of a program) happen to produce adjacent white space characters.