[texhax] Positioning that depends on space available in the current line

[Steve Schwartz]

Alex,

On Mon, 2011-06-20 at 13:14 +0100, Aleksandar Zec wrote:
> Hello,
> 
> I would like to achieve this effect:
> 
> aaaaaaaaaaaaaaaaaaaaaaaaa
> aaaaaaaaaaaaaaaaaaaaaaaaa
> aaaaaaa             bbbbb
> 
> aaaaaaaaaaaaaaaaaaaaaaaaa
> aaaaaaaaaaaaaaaaaaaaaaaaa
> aaaaaaa
>    bbbbbbbbbbbbbbbbbbbbbb
> 
> 'aaa' is a normal paragraph text. 'bbb' is a signature that should be
> positioned
> 
> (1) on the right end of the last line if there is enough place;
> (2) in the next line if there is not enough place, right aligned.
> 
> Any package/trick to do this automatically?
> 
> Thank you in advance,
> Alex

Here's a macro I adapted from one I got from Phil Taylor via this group
some time ago. It is based on a macro to right-justify an end-of-proof
marker (a square) generalised to take an argument. I don't claim to
understand all the comments, but it works for me. [It doesn't work
inside display math mode for fairly obvious reasons, but I guess you
don't need that.] Looks similar to other fragments you've been sent.

Use as:  aaaaa\pushright{bbbbb}

---------------------------------

\def\pushright#1{{%        set up
    \parfillskip=0pt            % so \par doesnt push \square to left
    \widowpenalty=10000         % so we dont break the page before
\square
    \displaywidowpenalty=10000  % ditto
    \finalhyphendemerits=0      % TeXbook exercise 14.32
   %
   %                 horizontal
    \leavevmode                 % \nobreak means lines not pages
    \unskip                     % remove previous space or glue
    \nobreak                    % dont break lines
    \hfil                       % ragged right if we spill over
    \penalty50                  % discouragement to do so
    \hskip.2em                  % ensure some space
    \null                       % anchor following \hfill
    \hfill                      % push \square to right
    {#1}                        % the end-of-proof mark (or whatever)
   %
   %                   vertical
    \par}}                      % build paragraph

------------------
Steve

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