How to correctly use \newenvironment

Question

I would like to use a \newenvironment in my .tex file. It should use a serif font and should be left aligned.

Can someone show me the correct syntax?

Answer 1

Here are three ways of defining environments that use serif fonts (\rmfamily here in short) and aligning them to the left. The 3rd way with \NewEnviron uses \sffamily and alignment to the right in order to show the differences.

The \vskip\baselineskip is not necessary, just for visually separating them.

The regular way is \newenvironment, having

\newenvironment{environmentname}[number of args][value of optional argument]{begin code}{end code} -- the example here does not have arguments, so [] can be omitted there. Please note, that the arguments can not be accessed in the {end code} section.

With \NewDocumentEnvironment the syntax is 'similar':

\NewDocumentEnvironment{environmentname}{argument specifications}{begin code}{end code} -- here, the arguments can be used in the end code section.

\NewEnviron from environ package is different in some aspects:

\NewEnviron{environment name}[number of arguments][opt argument value]{environment start code\BODY}[environment end code}.

You need the \BODY macro in order to display the environment content -- this is collected first in \BODY. The end code is optional here.

\documentclass{article}

\usepackage{blindtext}
\usepackage{environ}
\usepackage{xparse}

\newenvironment{foo}{\rmfamily\flushleft}{\endflushleft}

\NewDocumentEnvironment{foobar}{}{\vskip\baselineskip\rmfamily\flushleft}{\endflushleft}

\NewEnviron{foobarbar}{\vskip\baselineskip\sffamily\flushright\BODY}[\endflushright]




\begin{document}
\begin{foo}
\blindtext
\end{foo}

\begin{foobar}
\blindtext
\end{foobar}

\begin{foobarbar}
\blindtext
\end{foobarbar}



\end{document}

Update with some font package loading

Just for example, I am using the bookman package for the Bookman font, which is a roman (serif) font by default -- there is no need to change \rmfamily then:

\documentclass{article}

\usepackage{blindtext}
\usepackage{environ}
\usepackage{xparse}

\usepackage{bookman}

\newenvironment{foo}{\rmfamily\flushleft}{\endflushleft}

\NewDocumentEnvironment{foobar}{}{\vskip\baselineskip\rmfamily\flushleft}{\endflushleft}

\NewEnviron{foobarbar}{\vskip\baselineskip\sffamily\flushright\BODY}[\endflushright]




\begin{document}
\begin{foo}
\blindtext
\end{foo}

\begin{foobar}
\blindtext
\end{foobar}

\begin{foobarbar}
\blindtext
\end{foobarbar}



\end{document}