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           H E W L E T T    /- hp -/    P A C K A R D
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   HP LABS - 3500 Deer Creek Road, Palo Alto, California 94304
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FROM: Bruce Nordman                DATE: 79-03-26
 
TO: PASCAL Users                SUBJECT: PASCAL Pretty-printer
 
     A Major trouble with most pretty-printers is that they  have
and  only  one output format.  As everyone has a different format
they prefer to see their programs appear in, options  are  needed
so  that  the  prettyprinter  can  be  adapted to an individual's
taste(or lack thereof).  Based on a pretty-printer  from  UBC,  I
have written such a program.  There are relatively few options at
this point(29), but as new ones are suggested, the list grows.    
                                                          
     Tidy will first  ask for options;  this can be terminated by
a ↑Z.  It will then ask for the  result file, then for the source
file.

     The pretty-printer  will  never  split  tokens  (except  for
some  comments)  and thus should always produce a program that is
still compilable.  In a  given  statement,  multiple  blanks  are
reduced  to  a  single blank, but single blanks are rarely elimi-
nated.  Attention is paid to the original format of  the  program 
when placing comments and statements.
 
     As not all comments are created  equal,  the  pretty-printer
classifies  each comment as one of 14 different types.  To decide
this, it uses the position it was in originally, what came before
it, what comes after it, how long it is, and other information.
 
     An option is set by giving it's name, and the value it is to 
be set to, i.e.  Density := 8; .  Notice that the  :=  and the  ;
are  ignored.    The pretty-printer ignores characters it doesn't
expect so that people can format  their  options  in  a  readable
fashion.    Also,  the  option names can be abbreviated up to the
amount shown in Upper case below, however case is ignored by  the
program.  To set the Density option to 8, dEn 8 and Density := 8;
are equivalent.  A numeric option (n) is  limited  to  the  range
0..99;  a  shift  option (s) is limited to 'A' for as is, 'L' for 
downshifting, 'M' for a leading uppercase followed by  lowercase,
and  'U'  for  upshifting;  and boolean options(b) are limited to
true and false, specified  by  '+'  and  '-'  respectively.   The
current options are:
 
 
 
Width n - The size of each input line, not including any line for 
          numbers present.  Default: 160.
                                                     
INdentation n - The number of spaces of indentation after a
          CONST, TYPE, VAR, procedure of function header, FOR,
          WITH, WHILE, IF, ELSE, or REPEAT.  RECORD and CASE
          indentations are separate options.  Default 3.
 
COntinuation←indent n - The number of extra spaces of indentation
          for continued lines.  Default: 6.
 
JOin←density n - A number in 0..99 which determines how much can
          be put on a given line when the statements were
          originally on separate lines.  The higher the number,
          the more dense the output.  Default 20.
 
DENsity n - A number in 0..99 which determines how much can be
          put on a given line when the statements were originally 
          on the same line.  The higher the number, the more
          dense the output.  Default: 70.
 
Comment Options:
Tab←comment n - The column at which many comments are put.
          Default: 35.
 
USe←tab b - Put many comments at Tab←comment.  Default: +.
 
FIt←comment b - Try to put comments on the same line as text even
          if the text extends beyond Tab←comment.  Default: +.
 
B←Comment b - Put comments after BEGIN's immediately after the
          BEGINs rather than at Tab←comment.  Default: -.
 
E←Comment b - Put comments after ENDs immediately after the ENDs
          rather than at Tab←comment.  Default: +.
 
JUstify←comment n - The rightmost column that will result in a
          comment at Starting←column.  Default: 2.
 
Absolute←comment n - The deviation from the output indent level
          of the position of a comment for the comment to be put
          at the current indent level.  Default: 10.             
 
Block Structure Options:
LEading←do b - DO and THEN printed at the left of the following
          statement.  Default: -.
 
B←Append b - BEGIN's are likely to be put on the same line as
          the phrase preceding them.  Default: -.

E←Append b - ENDs are likely to be put on the same line as the
          phrase preceding them.  Default: -.
 
BEgin←indent n - The amount of indentation for statements inside
          BEGIN-END blocks.  Default: 0.

Case←indent n - The amount of indentation for CASE statements.
          Default: 3.
 
FIeld←indent n - The amount of indentation for RECORD fields.
          Default: 3.
 
Other Formatting Options:
LAbel←out n - The maximum number of columns a label is set out
          from a statement.  Default: 15.
 
DEClaration←tab n - The minimum number of columns given for names
          before an '=' or ':' in declaratins.  Default: 12.
 
Name←limit n - The maximum number of columns for names in labels
          and variable lists.  Default: 80.

Output Appearance Options:
Out←width n - The maximum size of each output line.  Default: 72.
 
UNderline b - Underline reserved words.  Default: -.
 
BOldfaces n - The number of overprints of reserved words.
 
SPace←reserved b - Assure a space around many reserved words.
          Default: -.

Reserved←shift s - How to shift reserved words.  Default: As←is.
                                                     
ID←shift s - How to shift non-reserved identifiers.
          Default: As←is.
  
STarting←column n - The first column to use.  Default: 1.
  
     In addition to these options, the word SHow will display all
of the options and their current values, and the word Help may
be of help.                                          
                                                     
     Please report all bugs found, and all suggestions you have.