Underline just words, not the space between them

Question

I need to typeset a sentence such that just the words are underlined, and not the space between the words. Using the \underline will include the spaces between the words. I could do it with something like

\underline{The} \underline{quick} \underline{brown} \underline{fox} \underline{jumped} \underline{over} \underline{the} \underline{lazy} \underline{dog}

but it is too tedious and a painful thing to do. Also, the above line produces what is intended, but the spacing of the underline from the words is uneven. It would be really helpful if this is addressed in the answer as well. The above line produces this:

Is there a package or something easier to achieve this?

Answer 1

Let's make soul work less:

\documentclass{article}
\usepackage{xparse,soul}

\ExplSyntaxOn
\NewDocumentCommand{\ulns}{m}
 {
  \seq_set_split:Nnn \l_tmpa_seq { ~ } { #1 }
  \seq_map_inline:Nn \l_tmpa_seq { \ul{##1}~ } \unskip
 }
\ExplSyntaxOff

\begin{document}

\ulns{The quick brown fox jumped} over the lazy dog.

\end{document}

Basically, the argument is split at spaces; every fragment is fed to \ul and a space is added. The last one is removed by \unskip.

Answer 2

Package soul provides an underlining macro \textul/\ul with the same depth. The following example copies the driver to \textulw/\ulw and leaves the spaces without underline:

\documentclass{article}

\usepackage{soul}
\makeatletter
\DeclareRobustCommand*{\textulw}{%
  \SOUL@ulwsetup
  \SOUL@
}
\newcommand*{\SOUL@ulwsetup}{%
  \SOUL@setup
  \let\SOUL@preamble\SOUL@ulpreamble
  \let\SOUL@everysyllable\SOUL@uleverysyllable
  % \let\SOUL@everyspace\SOUL@uleveryspace % \SOUL@ulsetup
  \let\SOUL@everyhyphen\SOUL@uleveryhyphen
  \let\SOUL@everyexhyphen\SOUL@uleveryexhyphen
}
\let\ulw\textulw
\makeatother

\begin{document}
\ulw{The quick brown fox jumped over the lazy dog}.
\end{document}

Answer 3

Here's a LuaLaTeX-based solution. It doesn't require loading the soul package.

The user macro is called \ulow -- short for "underline only words". With \ulow, all non-letter glyphs, and not just whitespace, are exempt from being underlined.

The input is assumed to be UTF8-encoded. (ASCII is a proper subset of UTF8; thus, if your input file is pure ASCII, it's UTF8 automatically.)

If the argument of \ulow contains letters with descenders (g, j, p, q, or y), the lines below all words will be set with a generous amount of vertical whitespace. Conversely, if no letters with descenders are present, the spacing will be set more tightly. If you want the more generous spacing in all cases, simply replace the five-line if construct in the lua function with s = unicode.utf8.gsub (s, "(%a+)" , "\\underline{%1\\vphantom{p}}" ). (Even if you don't know Lua syntax, you may be able to guess that the term %a+ "captures" entire words, where a "word" can be any contiguous groups of uppercase and lowercase letters.)

% !TEX TS-program = lualatex
\documentclass{article}

\usepackage{fontspec}
\setmainfont{Latin Modern Roman} % set main document font

%% Lua-side code
\usepackage{luacode}
\begin{luacode}
function ulow ( s )
   if unicode.utf8.find ( s, "[gjpqy]") then -- any letters with descenders?
      s = unicode.utf8.gsub (s, "(%a+)" , "\\underline{%1\\vphantom{p}}" ) 
   else
      s = unicode.utf8.gsub (s, "(%a+)" , "\\underline{%1}" )
   end
   return ( tex.sprint ( s ) )
end
\end{luacode}

%% TeX-side code
\newcommand\ulow[1]{\directlua{ ulow ( \luastring {#1} ) }}

\begin{document}
\frenchspacing
\ulow{The quick brown fox jumps over the lazy dog.}

\bigskip
\ulow{El rápido zorro marrón saltó sobre el perro perezoso.}

\bigskip
\ulow{And, but; let: show? that. where (now), èéà äöü ÄÖÜß!}

\end{document}

Answer 4

FWIW, ConTeXt provides a macro for this: \underbars. In fact, all macros for horizontal rules--\underbar, \overstrike, and understrike--have a plural version which works at the word level.

\starttext

\startlines
\underbar {The quick brown fox jumped over the lazy dog}
\underbars{The quick brown fox jumped over the lazy dog}

\overstrike {The quick brown fox jumped over the lazy dog}
\overstrikes{The quick brown fox jumped over the lazy dog}

\understrike {The quick brown fox jumped over the lazy dog}
\understrikes{The quick brown fox jumped over the lazy dog}
\stoplines

\stoptext

which gives

It is possible to change the location of the line. For example, if you want to lower the underline, define a new bar with a larger offset (distance from baseline).

\definebar[lowerbar][underbar][offset=-0.6]
\definebar[lowerbars][lowerbar][continue=no]

\starttext

\startlines
\lowerbar {The quick brown fox jumped over the lazy dog}
\lowerbars{The quick brown fox jumped over the lazy dog}
\stoplines
\stoptext

which gives

Answer 5

Another "simple" macro-s without packages to slit by the spaces and then use \ul of the soul package in each word:

\def\UL#1{\expandafter\nusp#1 \nil}
\def\nusp#1 #2\nil{\ul{#1} \ifx\relax#2\relax\else\nusp#2\nil\fi}

As far I see, also \UL{} work well with line breaks, with or without descenders, and some other circumstances (see MWE code). The spaces are changed to \xspaces in the MWE to avoid the ending space when the argument is followed by a punctuation symbol (i.e. \UL{Some text}.).

\documentclass[a5paper,11pt]{article}
\parskip1em\parindent0em
\usepackage{soul,xspace,xcolor}

\def\UL#1{\expandafter\nusp#1 \nil}
\def\nusp#1 #2\nil{\ul{#1}\xspace\ifx\relax#2\relax\else\nusp#2\nil\fi}

\begin{document}
% Simple test
\UL{The quick brown fox} jumped over the lazy dog.\par
% Testing line breaks
\UL{The quick brown fox jumped over the lazy dog.
The quick brown fox jumped over the lazy dog.
The quick brown fox jumped over the lazy dog.} 
% Testing underline grouped words
\UL{The {quick brown fox} jumped over \mbox{the lazy dog}.}\par
% Testing if \xspace work
\UL{The quick brown fox jumped over the lazy dog}.\par  
% Testing the rule depth with/without descenders
The quick \UL{brown fox} jumped over the \UL{lazy dog}.\par
% Testing \UL nested in other formating commands
The \textbf{\UL{quick brown fox}} jumped over the {\em \UL{lazy dog}}.\par
% Testing commands inside \UL. Needed some grouping/boxing ...  
\UL{The 
\mbox{\fboxrule.5pt\fboxsep.5pt%
\fcolorbox{orange!20!yellow}{yellow!60}{quick brown fox}} 
jumped over the lazy dog}\par
\UL{The {\textsc{quick brown fox}} jumped over the lazy dog}\par
\end{document}

Answer 6

You can use pythonTeX too:

\documentclass{article}

\usepackage{pythontex}

\begin{document}
\begin{pythontex}
def under(string):
    spc = False
    out = ""
    for char in string:
        if spc == False:
            if char != " ":
                out= out + ("\underline{")
                out= out + char
                spc = True
        elif spc = True:
            if char == " ":
                out= out + "} "
                spc = False
            else:
                out= out + char
    out = out + "}"
    return out
\py{under(The quick brown fox jumped over the lazy dog)}
\end{pythontex}
\end{document}

I've considered that your string end is NOT a space and their is NO newline.

I can't show an output right now since I can't test the code where I am.