Demeter_in = <input> Input.                                                
Input :                                                                    
  Cd_graph                                                                 
    *common*.                                                              
Cd_graph = < adjacencies > Nlist(Adjacency)                                
  ["*terminal_sets*" <terminal_sets> Comma_list(Vertex) "."]               
  .                                                                        
Adjacency =                                                                
  < source > Vertex                                                        
  < ns > Neighbors                                                         
  "." .                                                                    
Neighbors :                                                                
  Neighbors_wc |                                                           
  Repetit_n                                                                
  *common*.                                                                
Neighbors_wc :                                                             
  Construct_ns |                                                           
  Alternat_ns                                                              
  *common* < construct_ns > List(Any_vertex).                              
Construct_ns = "=".                                                        
Alternat_ns = ":"                                                          
  < alternat_ns > Bar_list(Term) [<common> Common].                        
Common = "*common*".                                                       
Repetit_n = "~" <sandwiched> Sandwich(Kernel).                             
Kernel = [ <nonempty> Term ]                                               
  "{" <repeated> Sandwich(Term) "}".                                       
Any_vertex :                                                               
  Opt_labeled_term                                                         
  | Optional_term                                                          
  | Syntax_vertex                                                          
  | Inherit_term                                                           
  *common*.                                                                
Vertex = < vertex_name > DemIdent .                                           
Syntax_vertex :                                                            
  Regular_syntax                                                           
  | Print_command                                                          
  *common*.                                                                
Regular_syntax  = < string > DemString .                                      
Print_command :                                                            
  Print_indent | Print_unindent | Print_skip | Print_space *common*.       
Print_indent = "+" .                                                       
Print_unindent = "-" .                                                     
Print_skip = "*l" .                                                        
Print_space = "*s" .                                                       
Opt_labeled_term :                                                         
  Labeled                                                                  
  | Regular                                                                
    *common* <vertex> Term.                                                
Regular = .                                                                
Labeled = "<" < label_name > DemIdent ">" .                                   
Inherit_term = "*inherit*" <inherited> Comma_list(Term).                   
Term :                                                                     
  Normal                                                                   
    *common* <vertex> Vertex                                               
  .                                                                        
Normal = .                                                                 
Optional_term = "[" <opt> Sandwich(Opt_labeled_term) "]".                  

List(S) ~ {S}.                                                             
Nlist(S) ~ S {S}.                                                          
Bar_list(S) ~ S {"|" S}.                                                   
Comma_list(S) ~ S {"," S}.                                                 
Sandwich(S) =                                                              
  <first> List(Syntax_vertex) <inner> S                                    
  <second> List(Syntax_vertex)                                             
  .                                                                        


Obj_graph = <adjacencies>  Comma_list(Object).
Object = <objType> Vertex <description> Obj_description.
Obj_description : DNone | DTerminal | DConstruction | DRepetition.
DNone = .
DTerminal = <value> DemString.
DConstruction = "(" <parts> List(Labeled_part) ")".
DRepetition = "{" [ <parts> Comma_list(Object) ] "}".
Labeled_part = <label> Label <obj> Object.
Label = "<" <lname> DemIdent ">".




Renames = "*rename*" <conversions> Comma_list (Conversion).
Conversion = <old_name> Name "=>" <new_name> Name.
Name = <name> DemIdent.


CDL_Algorithm = <obj_graph> Obj_graph
               ["*cd-in*" <cd_in> Demeter_in]
               ["*ren-in*" <ren_in> Renames]
                "*cd-out*" <cd_out> Cd_graph.