-- File: DBNamesImpl.mesa
-- last edited by Donahue, May 20, 1983 9:58 am
-- Last Edited by: Willie-sue, February 22, 1983 4:08 pm

DIRECTORY
  DB,
  DBEnvironment,
  DBNames,
  Atom,
  NutOps,
  Rope;
  
DBNamesImpl: CEDAR PROGRAM
  IMPORTS Rope, DB, Atom, DBEnvironment, NutOps

  EXPORTS DBNames =

  BEGIN OPEN Rope, DB, Atom;
  
  Separator: PUBLIC CHAR _ '!;
  
  Sep: ROPE = Rope.FromChar[Separator];
  
  EntityToName: PUBLIC PROC[ e: Entity, seg: DB.Segment _ NIL ] RETURNS[ name: ROPE ] = {
    IF NOT NutOps.IsSystemDomain[d: DomainOf[e]] THEN seg _ DB.SegmentOf[e];
    name _ Rope.Cat[ GetPName[seg], Sep, NameOf[DomainOf[e]], Sep, NameOf[e] ]};
  
  NameToEntity: PUBLIC PROC[ name: ROPE ] RETURNS[ e: Entity ] = {
    segNameLength: INT = Rope.Find[ name, Sep ];
    domainNameLength: INT = Rope.Find[ name, Sep, segNameLength+1 ] - segNameLength - 1;
    segName: ROPE = Rope.Substr[ name, 0, segNameLength ];
    domainName: ROPE = Rope.Substr[ name, segNameLength+1, domainNameLength ];
    entityName: ROPE = Rope.Substr[ name, segNameLength+domainNameLength+2 ];
    segment: DB.Segment = Atom.MakeAtom[ segName ];
    domain: Domain;
    domain _ DeclareDomain[ domainName, segment, Version[OldOnly] ! 
                    DBEnvironment.Error => CHECKED { domain _ NIL; CONTINUE } ];
    e _ IF domain = NIL THEN NIL
                ELSE FetchEntity[ domain, entityName, segment ] };
                
  SegmentOf: PUBLIC PROC[ name: ROPE ] RETURNS[ segment: DB.Segment ] = {
    segNameLength: INT = Rope.Find[ name, Sep ];
    segName: ROPE = Rope.Substr[ name, 0, segNameLength ];
    RETURN[ Atom.MakeAtom[ segName ] ] };
  
  END. . .