(* Copyright (C) 1990, Digital Equipment Corporation.         *)
(* All rights reserved.                                       *)
(* See the file COPYRIGHT for a full description.             *)

(* Last modified on Wed Mar 21 00:53:20 1990 by muller        *)


INTERFACE M3ASTRep;

(* This interface defines the private representation of Abstract Syntax 
   Trees.  It is intended to be implementation-dependent; containing 
   whatever decorations are appropriate for a particular compiler or 
   programming environment.  In particular, the M3ASTRep interface for 
   SRC Modula-3 is "owned" by the compiler and interpreter; other 
   clients would be wise to use the property list or a procedural 
   interface implemented by ASTRep.  
   
   It also reveals the representations of the other types that were 
   left unspecified, for example, M3Entity.Variable.  *)

IMPORT M3AST, M3Scope, M3Value;

(* Reveal the presence of scopes in those nodes that have them: *)

REVEAL 
  M3AST.Interface = 
    M3AST.CompilationUnit OBJECT 
      safe: BOOLEAN;
      name: Id;
      imports: REF ARRAY OF AST.Import;
      decls: REF ARRAY OF AST.Declaration;
    END OBJECT 
      scope: Scope.T 
    END;
  (* Notice that we repeat the prefix revealed in AST.i3, 
     and then extend it with the scope field.  Each node type will be 
     treated this way.  This means that if public fields are changed, 
     then both AST and ASTRep must be edited.  If either edit is
     forgotten, the compiler will flag the error.  This is consistent 
     with the way procedure signatures are handled in interfaces and 
     implementations. *)
      
  AST.Module = 
    CompilationUnit OBJECT
      safe: BOOLEAN;
      name: Id;
      imports: REF ARRAY OF AST.Import;
      exports: AST.IDlist;
      block: AST.Block
    END OBJECT 
      scope: Scope.T 
    END;
    
  M3AST.ProcDeclaration = ... OBJECT scope: Scope.T END;
  M3AST.ForStmt = ... OBJECT scope: Scope.T END;
  M3AST.TCase = ... OBJECT scope: Scope.T END;
  M3AST.Handler = ... OBJECT scope: Scope.T END;
  M3AST.WithBinding = ... OBJECT scope: Scope.T END;

(* Reveal the presence of the fields that resolve overloading: *)

  AST.Application = ... OBJECT op: M3Entity.Operation END;

(* Revelations concerning M3Entity.Variables: *)

REVEAL 
  M3Entity.Variable = M3Entity.T OBJECT ... END;
  M3Entity.Parameter = M3Entity.Variable OBJECT ... END;
  M3Entity.Local = M3Entity.Variable OBJECT ... END;
  M3Entity.Global = M3Entity.Variable OBJECT ... END;
  
(* ... here go the other revelations needed by the compiler 
   and interpreter ... *)
 
END M3ASTRep.