PROGRAM TITLE: Modula-2 PRETTYPRINTING PROGRAM                    
                                                                    
  PROGRAM NAME: PRETTY
                                                                    
  PROGRAM SUMMARY:                                                  
                                                                    
     This program takes as input a Modula-2 program and             
     reformats the program according to a standard set of           
     prettyprinting rules. The prettyprinted program is given       
     as output.  The prettyprinting rules are given below.          
                                                                    
     An important feature is the provision for the use of extra     
     spaces and extra blank lines. They may be freely inserted by   
     the user in addition to the spaces and blank lines inserted    
     by the prettyprinter.                                          
                                                                    
     No attempt is made to detect or correct syntactic errors in    
     the user's program.  However, syntactic errors may result in   
     erroneous prettyprinting.                                      
                                                                    
                                                                    
  INPUT FILE: a file of characters, presumably a                    
              Modula-2 program or program fragment                  
              (default extension .MOD).                             
                                                                    
  OUTPUT FILE: the prettyprinted program                            
               (default extension .NEW).                            
                                                                    
                                                                    
                                                                    



                                                                    
                  Modula-2 prettyprinting rules                     
                                                                    
                                                                    
  [ general prettyprinting rules ]                                  
                                                                    
   1.   Any spaces or blank lines beyond those generated by the     
     prettyprinter are left alone.  The user is encouraged, for the 
     sake of readability, to make use of this facility.             
        In addition, comments are left where they are found, unless 
     they are shifted right by preceeding text on a line.           
                                                                    
   2.   All statements and declarations begin on separate lines.    
                                                                    
   3.   No line may be greater than 80 characters long.  Any line   
     longer than this is continued on a separate line.              
                                                                    
   4.   The keywords "UNTIL", "ELSIF", "ELSE" are forced to start   
     on a new line.                                                 
                                                                    
   5.   A blank line is forced before the keywords "MODULE",        
     "PROCEDURE", "CONST", "TYPE", "VAR" and "BEGIN".               
                                                                    
   6.   A space is forced before and after the symbols ":=" and     
     "=". Additionally, a space is forced after the symbols ":".    
     Note that only "="s in declarations are formatted.  "="s  in   
     expressions are ignored.                                       
                                                                    
                                                                    
  [ indentation rules ]                                             
                                                                    
   1.   The bodies of "EXPORT", "IMPORT", "CONST", "TYPE", and      
     "VAR" declarations are indented from their corresponding       
     declaration header keywords.                                   
                                                                    
   2.   The bodies of "BEGIN-END", "REPEAT", "FOR", "WHILE", "LOOP" 
     "WITH", and "CASE" statements, as well as "RECORD" definitions 
     and "CASE" variants are indented from their header keywords.   
                                                                    
   3.   An "IF-THEN-ELSE" statement is indented as follows:         
                                                                    
             IF expression THEN                                     
               statement                                            
             ELSIF expression THEN                                  
               statement                                            
             ELSE                                                   
               statement                                            
             END                                                    
                                                                    
   4.   A "CASE" statement or variant declaration is indented       
     as follows:                                                    
                                                                    
             CASE ... OF                                            
               labels: 
                 statement or decalaration |                        
               labels:                                              
                 statement or decalaration |                        
             ELSE                                                   
               statement                                            
             END                                                    
                                                                    
   5.   Any text between the symbol pairs "()", "[]" and "{}" is    
     indented from the opening symbol.