%***************************************************************
% A simple enviroment for use of Dirac interpreter parse.m
% Because of global variable management it can be re-entered
%
% initilize:    Dirac
%               by entering  H:  or h:   or  ?  you get help
%               by entering    $   :  exit 
%***************************************************************
    format compact
    warning off
    ShowMat=0;
    blanc=' ';
    global GLOBALIZE; global DECLARED; 
    global InitDirac;
     if size(InitDirac) == [0 0]
        GLOBALIZE='global FileHnd ;'; DECLARED='';
        FileHnd=fopen('Dirac.cmd','w');
        InitDirac=1;
     else
        fprintf(1,'Declared: %s\n', DECLARED)
        FileHnd=fopen('Dirac.cmd','a');  
     end
    stopval=0;
 while stopval==0                
   eval(GLOBALIZE);
   InputStr=input('Dirac :   ','s');
   done=0; 
   leng=length(InputStr);
   if( leng<1)
         InputStr='%  ';
         leng=length(InputStr);
         done=1;       
   end   
   % cosmetics: remove blancs etc.
    while findstr(InputStr,[blanc blanc])~=[]
      InputStr=strrep(InputStr,[blanc blanc],blanc); 
    end
    %remove blanc at beginning and end
    if InputStr(length(InputStr))==blanc
       InputStr=InputStr(1:length(InputStr)-1) ; 
    end 
    if InputStr(1)==blanc
       InputStr=InputStr(2:length(InputStr)) ;
    end 
   % cosmetics done     
   leng=length(InputStr);
   if InputStr(1:1) == '$'
      stopval=1;
      fclose( FileHnd);
      done=1;
   else
      if( leng<1)
         InputStr='%'
         done=1;       
      end
      if InputStr(1) == '?'
         ! cat DiracHelp.txt
         done=1;       
      end
      if InputStr(1) == '%'
          fprintf( FileHnd,'%s\n',InputStr);
          done=1;
      end
      Procent= findstr(InputStr,'%');
      if Procent ~= []
           if done~=1
              fprintf( FileHnd,'%s\n',InputStr(Procent(1):leng));
           end
           InputStr=InputStr(1:Procent(1)-1);
      end        
      if(leng>1 & done~=1 )
         if strcmp(InputStr(1:2),'D:')==1
           fprintf( FileHnd,'%s\n',InputStr);
           InputStr=InputStr(3:leng);
           Declare(InputStr); 
           %  is in Declare.m DECLARED=[DECLARED InputStr ' ' ];
           eval(GLOBALIZE);
           done=1;
         elseif strcmp(InputStr(1:2),'M:')==1
           fprintf( FileHnd,'%s\n',InputStr);
           InputStr=InputStr(3:leng);
           eval(InputStr);
           done=1;         
         elseif strcmp(InputStr(1:2),'H:')==1
           krise=[ '! cat ' pwd '/DiracHelp.txt' ];
           eval(krise);
           done=1;                   
         elseif strcmp(InputStr(1:2),'h:')==1
            krise=[ '! more ' pwd '/DiracHelp.txt' ];
           eval(krise);
           done=1;
         elseif strcmp(InputStr(1:2),'e:')==1
            krise=[ '!more ' pwd '/example2.txt'];
           done=1; 
           eval(krise);
         elseif strcmp(InputStr(1:2),'E:')==1
            krise=[ '! more ' pwd '/example3.txt'];
           eval(krise);
           done=1; 
         elseif strcmp(InputStr(1:2),'G:')==1
           fprintf(1,'Statement: %s\n\n', GLOBALIZE)
           fprintf(1,'Declared : %s\n', DECLARED)
           done=1; 
         elseif strcmp(InputStr(1:2),'S:')==1
             if(ShowMat==0)
                ShowMat=1;
                fprintf(1,'Showing Matlab Command: Now ON \n')
             else
                ShowMat=0;
              fprintf(1,'Showing Matlab Command: Now OFF \n')             
             end
           done=1; 
         elseif strcmp(InputStr(1:2),'c:')==1
           more on           
            krise=[ '! more ' pwd '/Dirac.cmd'];
           eval(krise);
           more off
           done=1;                            
         end                 
      end          
      if done ~= 1 
           fprintf( FileHnd,'%s\n',InputStr);
           OutStr=parse(InputStr);
           if(ShowMat==1)
             fprintf(1,'Matlab:   -->    %s\n',OutStr);
           end
           eval(OutStr);
      end 
    end  % if not stop ( stopval=1; )          
  end   % while