indent.1

早期freebsd实现

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.\"	@(#)indent.1	8.1 (Berkeley) 7/1/93
.\"
.Dd July 1, 1993
.Dt INDENT 1
.Os BSD 4.2
.Sh NAME
.Nm indent
.Nd indent and format C program source
.Sh SYNOPSIS
.Nm indent
.Op Ar input-file Op Ar output-file
.Op Fl bad | Fl nbad
.Op Fl bap | Fl nbap
.Bk -words
.Op Fl bbb | Fl nbbb
.Ek
.Op Fl \&bc | Fl nbc
.Op Fl \&bl
.Op Fl \&br
.Op Fl c Ns Ar n
.Op Fl \&cd Ns Ar n
.Bk -words
.Op Fl cdb | Fl ncdb
.Ek
.Op Fl \&ce | Fl nce
.Op Fl \&ci Ns Ar n
.Op Fl cli Ns Ar n
.Op Fl d Ns Ar n
.Op Fl \&di Ns Ar n
.Bk -words
.Op Fl fc1 | Fl nfc1
.Ek
.Op Fl i Ns Ar n
.Op Fl \&ip | Fl nip
.Op Fl l Ns Ar n
.Op Fl \&lc Ns Ar n
.Op Fl \&lp | Fl nlp
.Op Fl npro
.Op Fl pcs | Fl npcs
.Op Fl psl | Fl npsl
.Op Fl \&sc | Fl nsc
.Bk -words
.Op Fl sob | Fl nsob
.Ek
.Op Fl \&st
.Op Fl troff
.Op Fl v | Fl \&nv
.Sh DESCRIPTION
.Nm Indent
is a
.Ar C
program formatter.  It reformats the
.Ar C
program in the
.Ar input-file
according to the switches.  The switches which can be
specified are described below. They may appear before or after the file
names.
.Pp
.Sy NOTE  :
If you only specify an
.Ar input-file  ,
the formatting is
done `in-place', that is, the formatted file is written back into
.Ar input-file
and a backup copy of
.Ar input-file
is written in the current directory.  If
.Ar input-file
is named
.Sq Pa /blah/blah/file ,
the backup file is named
.Pa file.BAK .
.Pp
If
.Ar output-file
is specified,
.Nm indent
checks to make sure it is different from
.Ar input-file  .
.Pp
The options listed below control the formatting style imposed by
.Nm indent  .
.Bl -tag -width Op
.It Fl bad , nbad
If
.Fl bad
is specified, a blank line is forced after every block of
declarations.  Default:
.Fl nbad  .
.It Fl bap , nbap
If
.Fl bap
is specified, a blank line is forced after every procedure body.  Default:
.Fl nbap .
.It Fl bbb , nbbb
If
.Fl bbb
is specified, a blank line is forced before every block comment.  Default:
.Fl nbbb .
.It Fl \&bc , nbc
If
.Fl \&bc
is specified, then a newline is forced after each comma in a declaration.
.Fl nbc
turns off this option.  The default is
.Fl \&bc  .
.It Fl \&br , \&bl
Specifying
.Fl \&bl
lines up compound statements like this:
.ne 4
.Bd -literal -offset indent
if (...)
{
  code
}
.Ed
.Pp
Specifying
.Fl \&br
(the default) makes them look like this:
.ne 3
.Bd -literal -offset indent
if (...) {
  code
}
.Ed
.Pp
.It Fl c n
The column in which comments on code start.  The default is 33.
.It Fl cd n
The column in which comments on declarations start.  The default
is for these comments to start in the same column as those on code.
.It Fl cdb , ncdb
Enables (disables) the placement of comment delimiters on blank lines.  With
this option enabled, comments look like this:
.Bd -literal -offset indent
.ne 3
	/*
	* this is a comment
	*/
.Ed
.Pp
Rather than like this:
.Bd -literal -offset indent
	/* this is a comment */
.Ed
.Pp
This only affects block comments, not comments to the right of
code.  The default is
.Fl cdb  .
.It Fl ce , nce
Enables (disables) forcing `else's to cuddle up to the immediately preceding
`}'.  The default is
.Fl \&ce  .
.It Fl \&ci Ns Ar n 
Sets the continuation indent to be
.Ar n  .
Continuation
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 nesting, unless
.Fl \&lp
is in effect.
.Fl \&ci
defaults to the same value as
.Fl i  .
.It Fl cli Ns Ar n 
Causes case labels to be indented
.Ar n
tab stops to the right of the containing
.Ic switch
statement.
.Fl cli0 .5
causes case labels to be indented half a tab stop.  The
default is
.Fl cli0  .
.It Fl d Ns Ar n 
Controls the placement of comments which are not to the
right of code.  The default
.Fl \&d\&1
means that such comments are placed one indentation level to the
left of code.  Specifying
.Fl \&d\&0
lines up these comments with the code.  See the section on comment
indentation below.
.It Fl \&di Ns Ar n 
Specifies the indentation, in character positions, from a declaration keyword
to the following identifier.  The default is
.Fl di16  .
.It Fl dj , ndj
.Fl \&dj
left justifies declarations.
.Fl ndj
indents declarations the same as code.  The default is
.Fl ndj  .
.It Fl \&ei , nei
Enables (disables) special
.Ic else-if
processing.  If it's enabled, an
.Ic if
following an
.Ic else
will have the same indentation as the preceding
.Ic \&if
statement.
.It Fl 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,
.Fl nfc1
should be
used.  The default is
.Fl fc1  .
.It Fl i Ns Ar n 
The number of spaces for one indentation level.  The default is 4.
.It Fl \&ip , nip
Enables (disables) the indentation of parameter declarations from the left
margin.  The default is
.Fl \&ip  .
.It Fl l Ns Ar n 
Maximum length of an output line.  The default is 75.
.It Fl \&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
.Fl nlp
in effect:
.ne 2
.Bd -literal -offset indent
p1 = first_procedure(second_procedure(p2, p3),
\ \ third_procedure(p4,p5));
.Ed
.Pp
.ne 5
With
.Fl lp
in effect (the default) the code looks somewhat clearer:
.Bd -literal -offset indent
p1\ =\ first_procedure(second_procedure(p2,\ p3),
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ third_procedure(p4,p5));
.Ed
.Pp
.ne 5
Inserting two more newlines we get:
.Bd -literal -offset indent
p1\ =\ first_procedure(second_procedure(p2,
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ p3),
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ third_procedure(p4
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ p5));
.Ed
.It Fl npro
Causes the profile files,
.Sq Pa ./.indent.pro
and
.Sq Pa ~/.indent.pro ,
to be ignored.
.It Fl pcs , npcs
If true
.Pq Fl pcs
all procedure calls will have a space inserted between
the name and the `('.  The default is
.Fl npcs  .
.It Fl psl , npsl
If true
.Pq Fl 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
.Fl psl  .
.It Fl \&sc , nsc
Enables (disables) the placement of asterisks (`*'s) at the left edge of all
comments.
.It Fl sob , nsob
If
.Fl sob
is specified, indent will swallow optional blank lines.  You can use this to
get rid of blank lines after declarations.  Default:
.Fl nsob  .
.It Fl \&st
Causes
.Nm indent
to take its input from stdin, and put its output to stdout.
.It Fl T Ns Ar typename 
Adds
.Ar typename
to the list of type keywords.  Names accumulate:
.Fl T
can be specified more than once.  You need to specify all the typenames that
appear in your program that are defined by
.Ic typedef
\- 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:
.Ic typedef
causes a syntactic change in the
language and
.Nm indent
can't find all
instances of
.Ic typedef .
.It Fl troff
Causes
.Nm indent
to format the program for processing by
.Xr troff 1 .
It will produce a fancy
listing in much the same spirit as
.Xr vgrind 1 .
If the output file is not specified, the default is standard output,
rather than formatting in place.
.It Fl v , \&nv
.Fl v
turns on `verbose' mode;
.Fl \&nv
turns it off.  When in verbose mode,
.Nm indent
reports when it splits one line of input into two or more lines of output,
and gives some size statistics at completion. The default is
.Fl \&nv  .
.El
.Pp
You may set up your own `profile' of defaults to
.Nm indent
by creating a file called
.Pa .indent.pro
in your login directory and/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
.Nm 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.
.Pp
.Ss Comments
.Sq Em Box
.Em comments .
.Nm 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.
.Pp
.Em Straight text .
All other comments are treated as straight text.
.Nm Indent
fits as many words (separated by blanks, tabs, or newlines) on a
line as possible.  Blank lines break paragraphs.
.Pp
.Ss Comment indentation
If a comment is on a line with code it is started in the `comment column',
which is set by the
.Fl c Ns Ns Ar n 
command line parameter.  Otherwise, the comment is started at
.Ar n
indentation levels less than where code is currently being placed, where
.Ar n
is specified by the
.Fl d Ns Ns Ar n 
command line parameter.  If the code on a line extends past the comment
column, the comment starts further to the right, and the right margin may be
automatically extended in extreme cases.
.Pp
.Ss Preprocessor lines
In general,
.Nm indent
leaves preprocessor lines alone.  The only
reformatting that it will do is to straighten up trailing comments.  It
leaves embedded comments alone.  Conditional compilation
.Pq Ic #ifdef...#endif
is recognized and
.Nm indent
attempts to correctly
compensate for the syntactic peculiarities introduced.
.Pp
.Ss C syntax
.Nm 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:
.Pp
.Dl #define forever for(;;)
.Pp
is handled properly.
.Sh ENVIRONMENT
.Nm Indent
uses the
.Ev HOME
environment variable.
.Sh FILES
.Bl -tag -width "./.indent.pro" -compact
.It Pa ./.indent.pro
profile file
.It Pa ~/.indent.pro
profile file
.El
.Sh HISTORY
The
.Nm indent
command appeared in
.Bx 4.2 .
.Sh BUGS
.Nm Indent
has even more switches than
.Xr ls 1 .
.Pp
.ne 5
A common mistake that often causes grief is typing:
.Pp
.Dl indent *.c
.Pp
to the shell in an attempt to indent all the
.Nm C
programs in a directory.
This is probably a bug, not a feature.