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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