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Re: RFC: Perl manual pages -- update to follow the perlstyle.pod guidelines

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Tom Christiansen
April 6, 2010 09:03
Re: RFC: Perl manual pages -- update to follow the perlstyle.pod guidelines
Message ID:
In-Reply-To: Message from Andy Dougherty <>
   of "Tue, 06 Apr 2010 10:43:55 EDT." 

> On Tue, 6 Apr 2010, Nicholas Clark wrote:

>> What is the default nroff line length?

> I believe it traditionally has been 65 characters.  (Well, 6.5 inches, 
> with 10 characters per inch.)  However, most lines (except for headings) 
> also end up indented by some amount (traditionally 5 characters), and 
> items in a list (such as this list in perfunc.pod) are indented further. 
> Contending against this, that line is in a verbatim block, and is rendered 
> in "nofill" mode, so it can overflow the 65 character limit.  What happens 
> then is not well defined.

I tested nroff output not input exactly because of what you point out:
in practice, it is difficult to know beforehand which lines will wind
up being "too long", since this varies depending on surrounding context.

> Practically speaking, either will probably render ok on most man page 
> viewers these days.

I believe you're right, Andy, and information won't be lost; I know of no
system where lines are truncated as could once upon a time occur.  Still,
neither horizontal scrolling nor wrapping at screen-edge is as pleasing
to the eye as carefully doing so manually, so I try to do that whenever
reasonable--just as I do with these postings.

Though still widely followed, Henry's original Ten Commandments for C
Programmers did *not* include the now-apocryphal directive that "Thou
shalt forever honor the punchcard's 80-column limit and keep it wholly."
Dennis once famously remarked, "The notion of a 'record' is an obsolete
remnant of the days of the 80-column card."  And Larry notably quipped,
"You want it in one line?  Does it have to fit in 80 columns? :-)"


 * use font "monospace"; 
         1         2         3         4         5         6         7         8
               With EXPR, it returns some extra information that               |
               the debugger uses to print a stack trace.  The                  |
               value of EXPR indicates how many call frames to go              |
               back before the current one.                                    |
                   #  0         1          2      3            4               |
                   ($package, $filename, $line, $subroutine, $hasargs,         |
                   #  5          6          7            8       9         10  |
                   $wantarray, $evaltext, $is_require, $hints, $bitmask, $hinthash)
                    = caller($i);                                              |
               Here $subroutine may be "(eval)" if the frame is                |
               not a subroutine call, but an "eval".  In such a                |
               case additional elements $evaltext and $is_require              |
               are set: $is_require is true if the frame is                    |
               created by a "require" or "use" statement,                      |
               $evaltext contains the text of the "eval EXPR"                  |
               statement.  In particular, for an "eval BLOCK"                  |
         1         2         3         4         5         6         7         8


    "Tool Talk" by Peter Collinson; p. 22 of SunExpert Magazine, August 1998.

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