Force paragraph to stay with previous

Question

I am using knitr to create inline sparkline-esque graphics. However, when knitr inserts images that it generates with R, it add a blank line, which forces LaTeX to make a new paragraph.

That is, if I have text like this (not actual knitr code...):

Lorem ipsum dolor sit amet KNITR_FIGURE_HERE Ut enim ad minim veniam, quis nostrud exercitation.

It will generate TeX output like this

Lorem ipsum dolor sit amet
\begin{knitrout}
\includegraphics{path_to_figure} 

\end{knitrout}

Ut enim ad minim veniam, quis nostrud exercitation.

Which then forces the remaining text in the paragraph into a new paragraph. If I manually remove the blank line in the knitrout environment, it works inline as expected.

Hacking the knitr output to remove the blank line is non-trivial, so I'm wondering if there's a TeX command that can force a paragraph to be part of the previous one, regardless of new lines. For example, assuming \keepwithprevious is this hypothetical command...

Lorem ipsum dolor sit amet.

\keepwithprevious Ut enim ad minim veniam, quis nostrud exercitation.

...would result in this when typeset:

Lorem ipsum dolor sit amet. Ut enim ad minim veniam, quis nostrud exercitation.

Is there a way to do this in TeX?

Answer 1

Here is an approach not really involving TeX. The knitr code that generates the TeX output was not contained in the question. So I made up the following minimal example knitr-inline.Rnw that creates a similar TeX output. Furthermore, my knitr code automatically removes the empty line at the end of the "knitrout" environment. The idea is to replace "newline+newline+\end{knitrout}" by "newline+\end{knitrout}" using gsub at the document hook in R.

\documentclass{article}
\begin{document}
<<setup, echo=FALSE>>=
knit_hooks$set(document = function(x) {
  gsub('(\n\n\\\\end\\{knitrout\\}[\n]+)', '\n\\\\end\\{knitrout\\}\n', paste(x, collapse = '\n'))
})
@

Here is some text followed by a picture
<<echo=FALSE, out.width="11mm">>=
r <- rlnorm(8)
pie(r)
@
and the text continues for another line.

This is a new paragraph, which is indented as usual.
\end{document}

Running library(knitr);knitr(knitr-inline.Rnw) in R creates knitr-inline.tex. Compling it with "pdflatex" gives:

Answer 2

Below example works for me (based on Command that gobbles all following empty lines)

\documentclass{article}
\usepackage{color}
\newenvironment{knitrout}{}{}  %just a dummy environment
\makeatletter
\newcommand\gobblepars{%
    \@ifnextchar\par%
        {\expandafter\gobblepars\@gobble}%
        {}}
\makeatother

\begin{document}
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam
lobortis facilisis%
\begin{knitrout}
\color{red} sem. Nullam\gobblepars

\end{knitrout}
 nec mi et neque pharetra sollicitudin. Praesent imperdiet mi nec ante.

Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam
lobortis facilisis 
sem. Nullam 
nec mi et neque pharetra sollicitudin. Praesent imperdiet mi nec ante.
\end{document}

Note the spacing. It looks identical with and without environment.