Good C Beautifiers?

Gary Jackoway gary at hpavla.AVO.HP.COM
Thu Jan 25 01:30:17 AEST 1990


Thanks for all the responses.
Everybody mentioned the "indent" program.  Chris Mathes gave me a way
of getting at the program (which is not on my machine):

> Try 'indent', based on Berkley's version.  I like it because it has a
> bewildering array of options that you can toggle/specify.  It should be
> in volume18 of the comp.sources.unix archives.  You can anonymous ftp it
> from uunet.uu.net.

I'm still interested in beautifiers OTHER than indent, although indent
looks quite sufficient.  

For reference, here's the manual page to indent, courtesy of Raymond Chen:

NAME
     indent - indent and format C program source

SYNOPSIS
     indent  [ input-file [ output-file  ]  ]  [ -bacc | -nbacc ]
            [ -bad | -nbad ]   [ -bap | -nbap ]  [ -bbb | -nbbb ]
            [ -bc | -nbc ] [ -bl ] [ -br ] [ -bs | -nbs ] [ -cn ]
            [ -cdn ]   [ -cdb | -ncdb ]  [ -ce | -nce ]  [ -cin ]
            [ -clin ]    [ -dn ]    [ -din ]     [ -eei | -neei ]
            [ -fc1 | -nfc1 ]   [ -in ]   [ -ip | -nip ]   [ -ln ]
            [ -lcn ]  [ -lp | -nlp ]  [ -pcs | -npcs ]  [ -npro ]
            [ -psl | -npsl ]    [ -sc | -nsc ]   [ -sob | -nsob ]
            [ -st ] [ -troff ] [ -v | -nv ]

DESCRIPTION
     Indent is a C program formatter.  It reformats the C program
     in  the  input-file according to the switches.  The switches
     which can be specified are described below. They may  appear
     before or after the file names.

     NOTE: If you only specify an input-file, the  formatting  is
     done `in-place', that is, the formatted file is written back
     into input-file and a backup copy of input-file  is  written
     in   the   current   directory.    If  input-file  is  named
     `/blah/blah/file', the backup file is named file.BAK.

     If output-file is specified, indent checks to make  sure  it
     is different from input-file.

OPTIONS
     The  options  listed  below  control  the  formatting  style
     imposed by indent.

     -bap,-nbap     If -bap is specified, a blank line is  forced
                    after every procedure body.  Default: -nbap.

     -bacc,-nbacc   If -bacc is specified, a blank line is forced
                    around  every  conditional compilation block.
                    ie. in front of every #ifdef and after  every
                    #endif.   Other  blanklines surrounding these
                    will be swallowed.  Default: -nbacc.

     -bad,-nbad     If -bad is specified, a blank line is  forced
                    after  every block of declarations.  Default:
                    -nbad.

     -bbb,-nbbb     If -bbb is specified, a blank line is  forced
                    before every block comment.  Default: -nbbb.

     -bc,-nbc       If -bc is specified, then a newline is forced
                    after each comma in a declaration. -nbc turns
                    off this option.  The default is -bc.

     -br,-bl        Specifying -bl lines up  compound  statements
                    like this:
                        if (...)
                        {
                            code
                        }
                    Specifying -br (the default) makes them  look
                    like this:
                        if (...) {
                            code
                        }

     -bs,-nbs       Enables (disables) the  forcing  of  a  blank
                    after   sizeof.   Some  people  believe  that
                    sizeof should appear as though it were a pro-
                    cedure call (-nbs, the default) and some peo-
                    ple believe that since sizeof is an operator,
                    it  should  always  be  treated  that way and
                    should always have a blank after it.

     -cn            The column in which comments on  code  start.
                    The default is 33.

     -cdn           The column in which comments on  declarations
                    start.   The default is for these comments to
                    start in the same column as those on code.

     -cdb,-ncdb     Enables (disables) the placement  of  comment
                    delimiters  on blank lines.  With this option
                    enabled, comments look like this:
                         /*
                          * this is a comment
                          */
                    Rather than like this:
                         /* this is a comment */
                    This only affects block  comments,  not  com-
                    ments  to  the  right of code. The default is
                    -cdb .

     -ce,-nce       Enables (disables) forcing `else's to  cuddle
                    up  to  the  immediatly  preceeding `}'.  The
                    default is -ce .

     -cin           Sets the continuation indent to be  n.   Con-
                    tinuation  lines  will  be  indented that far
                    from the beginning of the first line  of  the
                    statement.   Parenthesized  expressions  have
                    extra indentation added to indicate the nest-
                    ing,  unless  -lp is in effect.  -ci defaults
                    to the same value as -i.

     -clin          Causes case labels to be indented n tab stops
                    to  the right of the containing switch state-
                    ment.   -cli0.5  causes  case  labels  to  be
                    indented  half  a  tab  stop.  The default is
                    -cli0 .

     -dn            Controls the placement of comments which  are
                    not  to  the  right of code.  The default -d1
                    means  that  such  comments  are  placed  one
                    indentation   level  to  the  left  of  code.
                    Specifying -d0 lines up these  comments  with
                    the  code.  See the section on comment inden-
                    tation below.

     -din           Specifies the indentation, in character posi-
                    tions, from a declaration keyword to the fol-
                    lowing identifier.  The default is -di16 .

     -eei,-neei     If -eei is specified,  and  extra  expression
                    indent  is  applied  on continuation lines of
                    the expression  part  of  if()  and  while().
                    These continuation lines will be indented one
                    extra level - twice  instead  of  just  once.
                    This  is  to  avoid the confusion between the
                    continued expression and the  statement  that
                    follows the if() or while().  Default: -neei.

     -fc1,-nfc1     Enables (disables) the formatting of comments
                    that  start  in  column  1.   Often, comments
                    whose leading `/' is in column  1  have  been
                    carefully  hand  formatted by the programmer.
                    In such cases, -nfc1  should  be  used.   The
                    default is -fc1.

     -in            The number  of  spaces  for  one  indentation
                    level.  The default is 4.

     -ip,-nip       Enables (disables) the indentation of parame-
                    ter  declarations  from the left margin.  The
                    default is -ip .

     -ln            Maximum  length  of  an  output  line.    The
                    default is 75.

     -lcn           Sets the line length for block comments to n.
                    It  defaults  to  being the same as the usual
                    line length as specified with -l.

     -lp,-nlp       Lines up code surrounded  by  parenthesis  in
                    continuation  lines.   If  a  line has a left
                    paren which is not closed on that line,  then
                    continuation  lines will be lined up to start
                    at the character position just after the left
                    paren.   For  example, here is how a piece of
                    continued code looks with -nlp in effect:
                        p1 = first_procedure(second_procedure(p2, p3),
                            third_procedure(p4, p5));
                    With -lp in effect  (the  default)  the  code
                    looks somewhat clearer:
                        p1 = first_procedure(second_procedure(p2, p3),
                                             third_procedure(p4, p5));
                    Inserting a couple more newlines we get:
                        p1 = first_procedure(second_procedure(p2,
                                                              p3),
                                             third_procedure(p4,
                                                             p5));

     -npro          Causes the profile files, `./.indent.pro' and
                    `~/.indent.pro', to be ignored.

     -pcs , -npcs   If true (-pcs) all procedure calls will  have
                    a  space  inserted  between  the name and the
                    '('.  The default is -npcs

     -psl , -npsl   If true (-psl) the names of procedures  being
                    defined are placed in column 1 - their types,
                    if any, will be left on the  previous  lines.
                    The default is -psl

     -sc,-nsc       Enables (disables) the placement of asterisks
                    (`*'s) at the left edge of all comments.

     -sob,-nsob     If -sob is  specified,  indent  will  swallow
                    optional  blank  lines.   You can use this to
                    get rid of blank  lines  after  declarations.
                    Default: -nsob

     -st            Causes indent to take its input  from  stdin,
                    and put its output to stdout.

     -Ttypename     Adds typename to the list of  type  keywords.
                    Names  accumulate:  -T  can be specified more
                    than once.   You  need  to  specify  all  the
                    typenames  that  appear  in your program that
                    are defined by typedefs  -  nothing  will  be
                    harmed  if  you  miss  a few, but the program
                    won't be formatted as nicely  as  it  should.
                    This  sounds  like a painful thing to have to
                    do, but it's really a symptom of a problem in
                    C:  typedef  causes a syntactic change in the
                    laguage and indent can't find all typedefs.

     -troff         Causes indent to format the program for  pro-
                    cessing  by  troff.   It will produce a fancy
                    listing in much the same  spirit  as  vgrind.
                    If  the  output  file  is  not specified, the
                    default is standard output, rather than  for-
                    matting in place.

                    The usual way to get  a  troff'd  listing  is
                    with the command
                         indent -troff program.c | troff -mindent

     -v,-nv         -v turns on `verbose' mode, -nv turns it off.
                    When  in verbose mode, indent reports when it
                    splits one line of input  into  two  or  more
                    lines  of output, and gives some size statis-
                    tics at completion. The default is -nv.

FURTHER DESCRIPTION
     You may set up your own `profile' of defaults to  indent  by
     creating  a  file  called  .indent.pro  in either your login
     directory or the current directory  and  including  whatever
     switches you like.  A `.indent.pro' in the current directory
     takes precedence over the one in your login  directory.   If
     indent  is run and a profile file exists, then it is read to
     set up the program's  defaults.   Switches  on  the  command
     line,   though,   always  override  profile  switches.   The
     switches should be separated by spaces, tabs or newlines.

     Comments

     `Box' comments.  Indent assumes that any comment with a dash
     or  star  immediately  after  the start of comment (that is,
     `/*-' or `/**') is a comment surrounded by a box  of  stars.
     Each  line  of such a comment is left unchanged, except that
     its indentation may be adjusted to account for the change in
     indentation of the first line of the comment.

     Straight text.  All other comments are treated  as  straight
     text.  Indent fits as many words (separated by blanks, tabs,
     or newlines) on a line as possible.  Blank lines break para-
     graphs.

     Comment indentation

     If a comment is on a line with code it  is  started  in  the
     `comment  column',  which  is  set  by  the -cn command line
     parameter.  Otherwise, the comment is started at n  indenta-
     tion  levels less than where code is currently being placed,
     where n is specified by the -dn command line parameter.   If
     the code on a line extends past the comment column, the com-
     ment starts further to the right, and the right  margin  may
     be automatically extended in extreme cases.

     Preprocessor lines

     In general, indent leaves  preprocessor  lines  alone.   The
     only  reformmatting  that  it  will  do  is to straighten up
     trailing comments.  It leaves imbedded comments alone.  Con-
     ditional  compilation  (#ifdef...#endif)  is  recognized and
     indent attempts to correctly compensate  for  the  syntactic
     peculiarites introduced.

     C syntax

     Indent understands a substantial amount about the syntax  of
     C,  but  it  has  a `forgiving' parser.  It attempts to cope
     with the usual sorts of incomplete and misformed syntax.  In
     particular, the use of macros like:
             #define forever for(;;)
     is handled properly.

FILES
     ./.indent.pro  profile file
     ~/.indent.pro  profile file
     /usr/lib/tmac/tmac.indent     Troff   macro   package    for
     ``indent -troff'' output.

BUGS
     Indent has even more switches than ls.

     A common mistake that often causes grief is typing:
         indent *.c
     to the shell in an attempt to indent all the C programs in a
     directory.  This is probably a bug, not a feature.

     The -bs option splits an excessivly fine hair.

Gary Jackoway



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