Remove par indent from environment

Question

The real problem here is that I can't figure out how to modify an existing environment. The concrete thing I want to achieve follows below.

I'm pretty happy with what the framed package gives me with its shaded* environment. But I'd like to change two things:

The first paragraph in the environment should not start with indentation.

I want to rename the environment from shaded* to something else.

\documentclass{article}
\usepackage{lipsum, xcolor, framed}
    \definecolor{shadecolor}{gray}{.8}

\begin{document}
    \begin{shaded*}
        \lipsum[1-2]
    \end{shaded*}
\end{document}

enter image description here

to highlight code in a list, the lines have to be indented 8 spaces. unfortunately, i don't know any way to do this except manually, line by line. — barbara beeton, Apr 04 '15 at 13:34
@barbarabeeton A trick we ascribe to David Carlisle: use {} to add the four blank spaces, then add a line with only one character flush left before the code; select the code again, press {} and remove the additional line. — egreg, Apr 04 '15 at 13:37

score 4 · Accepted Answer · answered Apr 04 '15 at 14:10

4

Use the trick of \@afterheading (simplified):

\documentclass{article}
\usepackage{lipsum, xcolor, framed}
\definecolor{shadecolor}{gray}{.8}

\newenvironment{blurb}
 {\begin{shaded*}\everypar={{\setbox0=\lastbox}\everypar{}}}
 {\end{shaded*}}

\begin{document}

\begin{blurb}
\lipsum[1-2]
\end{blurb}

\end{document}

enter image description here

answered Apr 04 '15 at 14:10

egreg

1,121,712

You mean that this code is taken from what LaTeX does after a heading? – Sverre Apr 04 '15 at 14:51
1

@Sverre Yes, it's a nice trick that's also explained in the TeXbook. Since \everypar is invoked after the paragraph has been started and the indentation box has been inserted, {\setbox0=\lastbox} removes it (and \box0 doesn't even change, because it's done in a group). Then \everypar is reinitialized to empty. – egreg Apr 04 '15 at 14:57

score 4 · Answer 2 · answered Apr 04 '15 at 14:25

Using tcolorbox for a change (for academic purposes).

\documentclass{article}
\usepackage{lipsum}
\usepackage[most]{tcolorbox}
\definecolor{shadecolor}{gray}{.8}

\newtcolorbox{fancypar}[1][]{
    colback=shadecolor,
    boxsep=6pt,
    parbox=false,
    arc=0pt,
    outer arc=0pt,
    nobeforeafter,
    frame hidden,
    enhanced jigsaw,
    breakable,
    before=\par\noindent%
  }

\begin{document}

\begin{fancypar}
\lipsum[1-2]
\end{fancypar}

\end{document}

enter image description here

score 2 · Answer 3 · answered Apr 04 '15 at 13:38

The following might be what you're after:

enter image description here

\documentclass{article}
\usepackage{lipsum, xcolor, framed}
\definecolor{shadecolor}{gray}{.8}

\makeatletter
\newenvironment{myfancyshade}
  {\@nameuse{shaded*}\noindent\ignorespaces}
  {\@nameuse{endshaded*}}
\makeatother

\begin{document}

\begin{myfancyshade}
  \lipsum[1-2]
\end{myfancyshade}
\end{document}

The old shaded* environment is invoked using \@nameuse, but using the traditional environment name works as well. Paragraph indentation is avoided via \noindent, and any spurious spaces is dropped using \ignorespaces.

What do you mean by "using the traditional environment name works as well"? — Sverre, Apr 04 '15 at 13:39

Remove par indent from environment

3 Answers3

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