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Line 2238 Unix V6 Comment: You are not expected to understand this.

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Old 04-29-2009
Line 2238 Unix V6 Comment: You are not expected to understand this.
Here is the famous line 2238 of Unix V6 which is part of some of the most delicate parts of the kernel, context switching.

This comment received huge publicity and just may be the the most famous source code comment in computing history.

Code:
2230	/*
2231	 * If the new process paused because it was
2232	 * swapped out, set the stack level to the last call
3333	 * to savu(u_ssav).  This means that the return
2235	 * actually returns from the last routine which did
2236	 * the savu.
2237	 *
2238	 * You are not expected to understand this.
2239	 */
2240	if(rp->p_flag&SSWAP) {
2241		rp->p_flag =& ~SSWAP;
2242		aretu(u.u_ssav);
2243	}

Ref: Unix Sixth Edition Kernel Source Code, © Western Electric Company
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LEARN ABOUT MOJAVE

ppi::token::comment5.18

PPI::Token::Comment(3)					User Contributed Perl Documentation				    PPI::Token::Comment(3)

NAME

       PPI::Token::Comment - A comment in Perl source code

INHERITANCE

	 PPI::Token::Comment
	 isa PPI::Token
	     isa PPI::Element

SYNOPSIS

	 # This is a PPI::Token::Comment

	 print "Hello World!"; # So it this

	 $string =~ s/ foo  # This, unfortunately, is not :(
	       bar
	       /w;

DESCRIPTION

       In PPI, comments are represented by "PPI::Token::Comment" objects.

       These come in two flavours, line comment and inline comments.

       A "line comment" is a comment that stands on its own line. These comments hold their own newline and whitespace (both leading and trailing)
       as part of the one "PPI::Token::Comment" object.

       An inline comment is a comment that appears after some code, and continues to the end of the line. This does not include whitespace, and
       the terminating newlines is considered a separate PPI::Token::Whitespace token.

       This is largely a convenience, simplifying a lot of normal code relating to the common things people do with comments.

       Most commonly, it means when you "prune" or "delete" a comment, a line comment disappears taking the entire line with it, and an inline
       comment is removed from the inside of the line, allowing the newline to drop back onto the end of the code, as you would expect.

       It also means you can move comments around in blocks much more easily.

       For now, this is a suitably handy way to do things. However, I do reserve the right to change my mind on this one if it gets dangerously
       anachronistic somewhere down the line.

METHODS

       Only very limited methods are available, beyond those provided by our parent PPI::Token and PPI::Element classes.

   line
       The "line" accessor returns true if the "PPI::Token::Comment" is a line comment, or false if it is an inline comment.

SUPPORT

       See the support section in the main module.

AUTHOR

       Adam Kennedy <adamk@cpan.org>

COPYRIGHT

       Copyright 2001 - 2011 Adam Kennedy.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

       The full text of the license can be found in the LICENSE file included with this module.

perl v5.18.2							    2011-02-25						    PPI::Token::Comment(3)