Wrapping long lines that contain no spaces

Question

I need to format extremely long strings of text. I would like to be able to specify their width, and have them wrap, with or without some special symbol to indicate that the line is wrapped. The problem is, however, that these strings do not contain any spaces. Here's an example of what I would like:

\foo{2in}
{17823941237490812347123904712389407123408917234890123748912034712985712389012351}

So I would like to get an hbox containing this long number, but spanning several lines, so that I get a rectangle 2in wide.

Does anyone know of a package/trick/macro that does this?

Answer 1

You may try the seqsplit package.

Answer 2

Something along these lines perhaps:

\def\breaknumberanywhere{\hskip0pt\futurelet\next\breaknumberi}
\def\breaknumberi{\ifcat\next9\expandafter\breaknumberii\fi}
\def\breaknumberii#1{#1\breaknumberanywhere}

\def\foo#1#2{\vtop{\hsize=#1\rightskip=0pt plus 1fil \leftskip=0pt
  \noindent\breaknumberanywhere#2}}

Here is a long number:
\foo{2in}
{17823941237490812347123904712389407123408917234890123748912034712985712389012351}
\bye

(Edited to become a minimal working example, as requested in a comment. LaTeXifization left to the interested reader. I also set \leftskip in order to make \foo a bit more robust.)

Answer 3

Thorsten told you what package to use; just for completeness I give a compilable example:

\documentclass{article}
\usepackage{seqsplit}
\newcommand\foo[2]{%
    \begin{minipage}{#1}
    \seqsplit{#2}
    \end{minipage}
    }
\begin{document}
\foo{2in}
{17823941237490812347123904712389407123408917234890123748912034712985712389012351}
\end{document}

Answer 4

A general solution with expl3; the command \foo has an optional argument that can be any character or box to mark the splitting point. With varwidth we round the box width to what is really necessary.

\documentclass{article}
\usepackage{varwidth}
\usepackage{xparse}
\setlength{\parindent}{0pt} % just for the example
\ExplSyntaxOn
\NewDocumentCommand{\foo}{ O{} m m }
 { 
  % some setup for the particular problem
  \begin{varwidth}[t]{#2}
  % some padding on the right
  \skip_set:Nn \rightskip { 0pt plus .5em }
  % just in case
  \skip_set:Nn \leftskip { 0pt }
  % a strut to set the first row height
  \strut
% the main routine
  \mayer_foo:nnn { #1 } { #2 } { #3 }
% finish off with a strut (attached from the last digit)
  \strut
  \end{varwidth}
 }
\seq_new:N \l_mayer_input_seq
\cs_new_protected:Npn \mayer_foo:nnn #1 #2 #3
 {
  % split the input into pieces
  \seq_set_split:Nnn \l_mayer_input_seq { } { #3 }
% between any two pieces insert a discretionary
  \seq_use:Nn \l_mayer_input_seq { \discretionary{#1}{}{} }
 }
\ExplSyntaxOff
\begin{document}
\rule{2in}{0.4pt}
\foo{2in}
{17823941237490812347123904712389407123408917234890123748912034712985712389012351}
\foo[-]{2in}
{17823941237490812347123904712389407123408917234890123748912034712985712389012351}
\foo[*]{2in}
{17823941237490812347123904712389407123408917234890123748912034712985712389012351}
\bigskip
The box doesn't take more than the stated space\
(but it can be slightly less wide)
\medskip
\fbox{\foo{2in}
{17823941237490812347123904712389407123408917234890123748912034712985712389012351}}
\end{document}

For completeness, a version where the normal text width is used, without boxing.

\documentclass{article}
\ExplSyntaxOn
\NewDocumentCommand{\foo}{ O{} m }
 {% #1 = discretionary, #2 = number to split
  \mayer_foo:nn { #1 } { #2 }
 }
\cs_new_protected:Nn \mayer_foo:nn
 {
  \tl_map_inline:nn { #2 }
   {
    ##1 \nobreak\hspace{0pt plus 0.1pt}\discretionary{#1}{}{}
   }
 }
\ExplSyntaxOff
\begin{document}
\noindent
\foo{
  17823 94123 74908 12347 12390 47123 89407 12340 89172 34890 
  12374 89120 34712 98571 23890 12351 12374 89120 34712 98571
  17823 94123 74908 12347 12390 47123 89407 12340 89172 34890 
  12374 89120 34712 98571 23890 12351 12374 89120 34712 98571
  17823 94123 74908 12347 12390 47123 89407 12340 89172 34890 
  12374 89120 34712 98571 23890 12351 12374 89120 34712 98571
}
\noindent
\foo[-]{
  17823 94123 74908 12347 12390 47123 89407 12340 89172 34890 
  12374 89120 34712 98571 23890 12351 12374 89120 34712 98571
  17823 94123 74908 12347 12390 47123 89407 12340 89172 34890 
  12374 89120 34712 98571 23890 12351 12374 89120 34712 98571
  17823 94123 74908 12347 12390 47123 89407 12340 89172 34890 
  12374 89120 34712 98571 23890 12351 12374 89120 34712 98571
}
\noindent
\foo[\hbox{$*$}]{
  17823 94123 74908 12347 12390 47123 89407 12340 89172 34890 
  12374 89120 34712 98571 23890 12351 12374 89120 34712 98571
  17823 94123 74908 12347 12390 47123 89407 12340 89172 34890 
  12374 89120 34712 98571 23890 12351 12374 89120 34712 98571
  17823 94123 74908 12347 12390 47123 89407 12340 89172 34890 
  12374 89120 34712 98571 23890 12351 12374 89120 34712 98571
}
\end{document}

The example shows that if the discretionary to be used is something more complex than a character, it should be enclosed in \hbox.

Answer 5

This is a very old post. I am adding one solution, thinking that this answer may be helpful for any one who arrives here:

\documentclass{article}
\begin{document}

\makeatletter
\def\foo#1#2{%
  \parbox{#1}{\strut\@tfor\xx:=#2\do{%
    \xx\linebreak[0]%
  }\strut}%
}

\foo{2in}
{17823941237490812347123904712389407123408917234890123748912034712985712389012351}

\foo{3in}
{17823941237490812347123904712389407123408917234890123748912034712985712389012351}
\end{document}