PMI Language Elements

The VIDEOPMI language consists of the following elements: 

   *  Sections 
   *  User-defined functions 
   *  Expressions 
   *  PMI commands, identifiers, constants, variables, string-literals, 
      and comments 
 The language is not case-sensitive, so BOUTB and boutb represent the same 
 identifier. Throughout this section, Backus-Naur Form (BNF) grammar is 
 used to describe the syntax. Some examples are given in the text. Where 
 such examples are omitted, sample .PMI files accompanying the document 
 should be used as a reference.