Using multiple inheritance in GF. AR 15/9/2004.

The following diagrams show inheritance between abstract syntaxes in two simple systems.

                   TopCity
                  /   |    \
                 /    |     \
      SystemCity   UserCity  Top
        /      \   /     \
  System       City      User


                   TopMath
                  /   |    \
                 /    |     \
      SystemMath   UserMath  Top
        /      \   /     \
  System       Math      User


Idea of each module: 

  User            -- User's moves on any domain
  System          -- System's moves on any domain
  Top             -- grammar covering both kinds of moves
  X = Math, City  -- possible domains
  UserX           -- User's domain specific moves
  SystemX         -- System's domain specific moves
  TopX            -- all moves on the domain X

In parallel to the abstract syntax hierarchies, we have of course
hierarchies of concrete syntaxes for any language; this directory contains Eng.