The region directives are used to explicitly mark regions of source code. pp-region :: pp-start-regionconditional-sectionpp-end-regionpp-start-region :: whitespace#whitespaceregionpp-messagepp-end-region :: whitespace#whitespaceendregionpp-message No semantic meaning is attached to a region; regions are intended for use by the programmer or by automated tools to mark a section of source code. The message specified in a #region or #endregion directive likewise has no semantic meaning; it merely serves to identify the region. Matching #region and #endregion directives may have different pp-messages. The lexical processing of a region: corresponds exactly to the lexical processing of a conditional compilation directive of the form: