indent.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)indent.1	8.1	9/11/90
.TH indent 1
.SH Name
indent \- indent and format C program source
.SH Syntax
.B indent
\fIinput\fR
[\|\fIoutput\fR\|] [\|\fIflags\fR\|]
.SH Description
.NXB "indent command"
.NXB "C program" "formatting"
The
.PN indent
command
is intended primarily as a C program formatter.
Specifically,
.PN indent
indents code lines,
aligns comments,
inserts spaces around operators where necessary and
breaks up declaration lists as in ``int a,b,c;''.
.PP
The
.PN indent
command
does not break up long statements to make them fit within the
maximum line length, but it does flag lines that are too long.  Lines
are broken so that each statement starts a new line, and braces
appear alone on a line.  
Also, an attempt is made to line up identifiers in declarations.
.PP
The 
.I flags
that can be specified follow. They
can appear before or after the file names.
If the
.I output
file is omitted, the formatted file is written
back into
.I input
and a ``backup'' copy of
.I input
is written in the current directory.
If
.I input
is named ``/blah/blah/file'',
the backup file is
named ``.Bfile''.
If
.I output
is specified,
.PN indent
checks to make sure it is different from
.IR input .
.SH Options
.NXR "indent command" "options"
The following options are used to control the formatting
style imposed by
.PN indent :
.IP \fB\-l\fInnn\fR 12
Determines maximum length of output line.  The default is 75.
.IP \fB\-c\fInnn\fR 
Determines column in which comments start.  The default is 33.
.IP \fB\-cd\fInnn\fR 
Determines column in which comments on declarations start.  The default
is for these comments to start in the same column as other comments.
.IP \fB\-i\fInnn\fR 
Determines number of spaces for one indentation level.  The default is 4.
.IP \fB\-\|dj,\-\|ndj\fR 
Causes declarations to be left justified. 
.B \-ndj
causes
them to be indented the same as code.  The default is
.BR \-ndj .
.IP \fB\-\|v,\-\|nv\fR 
.B \-v 
turns on ``verbose'' mode,
.B \-nv
turns it off.  When in verbose mode,
.PN indent
reports when it 
splits one line of input into two or more lines of output,
and it gives some size statistics at completion. 
The default is
.BR \-nv .
.IP \fB\-\|bc,\-\|nbc\fR 
Forces newline after each comma in a declaration.  
.B \-nbc
turns off this option.  The default is
.BR \-bc .
.IP \fB\-d\fInnn\fR 
Controls the placement of comments
which are not to the right of code.
Specifying
.B \-d2
means that such comments are placed two
indentation levels to the left of code.
The default
.B \-d0
lines up these comments with the code.
See the section on comment indentation below.
.IP \fB\-\|br,\-\|bl\fR 
Specifying
.B \-bl
causes
complex statements to be lined up in a space order.  For example, 
.EX
   if (...)
   {
       code
   }
.EE
Specifying
.B \-br
(the default) makes them look like this:
.EX
   if (...) {
       code
   }
.EE
.PP
You may set up your own ``profile'' of defaults to
.PN indent
by creating the file ``.indent.pro'' in your login directory
and including whatever switches you like.
.NXR "indent command" "setting default formatting"
If
.PN 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 profile
file must be a single line of not more than 127 characters.
The switches should be separated on the line by spaces or tabs.
.PP
.B Multiline expressions
.NXR "indent command" "multiline expressions and"
.PP
The
.PN indent
command
does not break up complicated expressions that extend over multiple
lines.  However, it usually indents such expressions that have
already been broken up correctly.
Such an expression might look like the following:
.EX
x =
        (
            (Arbitrary parenthesized expression)
            +
            (
                (Parenthesized expression)
                *
                (Parenthesized expression)
            )
        );

.EE
.PP
.B Comments
.NXR "indent command" "comments recognized"
.PP
The
.PN indent
command
recognizes the following four kinds of comments:
.TP 4
1)
straight text
.TP
2)
``box'' comments
.TP
3)
UNIX-style comments
.TP
4) 
comments that should be passed through unchanged
.PP
The comments are interpreted as follows:
.TP 20
.I ``Box'' comments
The
.PN indent
command assumes that any comment with a dash
immediately after the start of comment (i.e. ``/*\-'')
is a comment surrounded by a box of stars.  Each line
of such a comment is left unchanged,
except that the first non-blank
character of each successive line is lined up with the beginning
slash of the first line.  Box comments are indented (see below).
.TP
.I ``Unix-style'' comments
This is the type of section header which is used 
extensively in the UNIX system source.  If the start
of comment (``/*'') appears on a
line by itself, 
.PN indent
assumes that it is a
UNIX-style comment.  These are
treated similarly to box comments, except
the first non-blank character on each
line is lined up with the `*' of the ``/*''.
.TP
.I Unchanged comments
Any comment which starts in column 1 is left completely
unchanged.  This is intended primarily for documentation header pages.
The check for unchanged comments is made before
the check for UNIX-style comments.
.TP
.I Straight text
All other comments are treated as straight text. 
.I Indent
fits
as many words (separated by blanks,
tabs, or new lines) on a line as possible.
Straight text comments are indented.
.PP
.B Comment indentation
.PP
Box, UNIX-style, and straight text comments may be indented.
If a comment is on a line
with code it is started in the ``comment
column'', which is set by the
.B \-cnnn
command line parameter.
Otherwise, the
comment is started at 
.I nnn
indentation levels less than where code is
currently being placed, where
.I nnn
is specified by the
.B \-dnnn
command line parameter.  (Indented
comments is never be placed in column 1.)
If the code on a line extends past the comment column,
the comment is moved to the next line.
.SH Restrictions
.NXR "indent command" "restricted"
Does not know how to format ``long'' declarations.
.SH Diagnostics
.NXR "indent command" "diagnostics"
Diagnostic error messages, mostly to
tell that a text line has been broken
or is too long for the output line.
.SH Files
.DT
\&.indent.pro	profile file
.NXE "indent command"
.NXE "C program" "formatting"