1.5 Comments

indent formats both C and C++ comments. C comments are begun with ‘/*’, terminated with ‘*/’ and may contain newline characters. C++ comments begin with the delimiter ‘//’ and end at the newline.

indent handles comments differently depending upon their context. indent attempts to distinguish between comments which follow statements, comments which follow declarations, comments following preprocessor directives, and comments which are not preceded by code of any sort, i.e., they begin the text of the line (although not necessarily in column 1).

indent further distinguishes between comments found outside of procedures and aggregates, and those found within them. In particular, comments beginning a line found within a procedure will be indented to the column at which code is currently indented. The exception to this is a comment beginning in the leftmost column; such a comment is output at that column.

indent attempts to leave boxed comments unmodified. The general idea of such a comment is that it is enclosed in a rectangle or “box” of stars or dashes to visually set it apart. More precisely, boxed comments are defined as those in which the initial ‘/*’ is followed immediately by the character ‘*’, ‘=’, ‘_’, or ‘-’, or those in which the beginning comment delimiter (‘/*’) is on a line by itself, and the following line begins with a ‘*’ in the same column as the star of the opening delimiter.

Examples of boxed comments are:

/**********************
 * Comment in a box!! *
 **********************/

       /*
        * A different kind of scent,
        * for a different kind of comment.
        */

indent attempts to leave boxed comments exactly as they are found in the source file. Thus the indentation of the comment is unchanged, and its length is not checked in any way. The only alteration made is that an embedded tab character may be converted into the appropriate number of spaces.

If the ‘-bbb’ option is specified, all such boxed comments will be preceded by a blank line, unless such a comment is preceded by code.

Comments which are not boxed comments may be formatted, which means that the line is broken to fit within a right margin and left-filled with whitespace. Single newlines are equivalent to a space, but blank lines (two or more newlines in a row) are taken to mean a paragraph break. Formatting of comments which begin after the first column is enabled with the ‘-fca’ option. To format those beginning in column one, specify ‘-fc1’. Such formatting is disabled by default.

The right margin for formatting defaults to 78, but may be changed with the ‘-lc’ option. If the margin specified does not allow the comment to be printed, the margin will be automatically extended for the duration of that comment. The margin is not respected if the comment is not being formatted.

If the comment begins a line (i.e., there is no program text to its left), it will be indented to the column it was found in unless the comment is within a block of code. In that case, such a comment will be aligned with the indented code of that block (unless the comment began in the first column). This alignment may be affected by the ‘-d’ option, which specifies an amount by which such comments are moved to the left, or unindented. For example, ‘-d2’ places comments two spaces to the left of code. By default, comments are aligned with code, unless they begin in the first column, in which case they are left there by default — to get them aligned with the code, specify ‘-fc1’.

Comments to the right of code will appear by default in column 33. This may be changed with one of three options. ‘-c’ will specify the column for comments following code, ‘-cd’ specifies the column for comments following declarations, and ‘-cp’ specifies the column for comments following preprocessor directives #else and #endif. ‘-dj’ together with ‘-cd0’ can be used to suppress alignment of comments to the right of declarations, causing the comment to follow one tabstop from the end of the declaration. Normally ‘-cd0’ causes ‘-c’ to become effective.

If the code to the left of the comment exceeds the beginning column, the comment column will be extended to the next tabstop column past the end of the code, or in the case of preprocessor directives, to one space past the end of the directive. This extension lasts only for the output of that particular comment.

The ‘-cdb’ option places the comment delimiters on blank lines. Thus, a single line comment like /* Loving hug */ can be transformed into:

/*
   Loving hug
 */

Stars can be placed at the beginning of multi-line comments with the ‘-sc’ option. Thus, the single-line comment above can be transformed (with ‘-cdb -sc’) into:

/*
 * Loving hug
 */

This document was generated by david on December, 15 2008 using texi2html 1.78.