The implementation of Moscow ML's interactive system

 * Structures used only to implement the interactive system:

    Predef.sml

      Allocation of the first 39 slots of the global_data array,
      corresponding to the runtime system's runtime/globals.h, from
      which the Predef.sml source file is generated automatically.

      The purpose is to enable interaction between the SML code of the
      interactive system and the (C code of the) runtime system.

      The values are formally bound in structure General, but since
      the names are not all in the compile-time environment exposed by
      the interactive system, they are not all accessible to the
      programmer.

    Prim_c.sml 

      An array of the names of the C primitives in the runtime system

    Symtable.sml 

    Patch.sml 

    Tr_const.sml

    Rtvals.sml 

    Load_phr.sml 
 
    Exec_phr.sml 

    Smltop.sml 

    Maint.sml


 * The built-in structure Meta is available in the interactive system
   only.  Its values are defined in compiler/Smltop.sml.  They are
   mostly hooks to SML functions used to implement the interactive
   system itself.  In mosml.net these names could be bound at
   load-time (or resolved at every use) using reflection.

 * 
