# Smart parentheses?

Is there a way of smartly nesting parentheses and square brackets (in text mode), so that LaTeX detects nesting relations and typesets them accordingly? I'm thinking in something like csquotes does with quotation marks. Something like:

\enparent{My outer layer \enparent{my inner lever \enparent{my innermost level}}}


with the result being:

(My outer layer [my inner level {my innermost level}])


I wonder if there is already an out-of-the-box solution for that.

A package? The following simple macro does it:

\documentclass{article}

\newcount\smcount
\def\smart#1{\ifcase\smcount(\or[\or\{\else TOO DEEP!\fi%

\begin{document}

\smart{Ala \smart{ma \smart {kota}}}

\end{document}


(Or, if you wish, not \smart but \enparent). Usage:

\smart{Ala \smart{ma \smart {kota}}}


• Nice try, but I get: (My outer layer [my inner lever {my innermost level}}]. – NVaughan Apr 25 '13 at 2:38
• I get: (Ala [ma {kota}}]. Any ideas? – NVaughan Apr 25 '13 at 2:48
• @NVaughan Fixed. The final space disappeared during copying. – Przemysław Scherwentke Apr 25 '13 at 2:49
• Do you really need all that extra white space in the image output? – azetina Apr 25 '13 at 19:35
• @azetina No, but I still have problems with trimming my PDF's and tranforming them onto PNG's. – Przemysław Scherwentke Apr 25 '13 at 19:39

For comparison I am posting a ConTeXt solution.

Such a macro already exists, albeit for quotes. One of the good things about ConTeXt is that a feature is never defined in a one-off basis. For example, instead of defining a macro for quotations that changes the quote symbol depending on the level of nesting, ConTeXt defines a generic delimitedtext mechanism and quotation is a special case of delimited text. The desired parenthesis macro is also a delimited text where the left and right symbol change depending on the level of nesting. So, use delimited text to define this macro as follows:

\definedelimitedtext[parenthesis]   [location=text]
\setupdelimitedtext [parenthesis:1] [left={(}, right={)}]
\setupdelimitedtext [parenthesis:2] [left={[}, right={]}]
\setupdelimitedtext [parenthesis:3] [left={\{},right={\}}]


This can be used as

\starttext
\parenthesis{My outer layer \parenthesis{my inner layer \parenthesis{my innermost layer}}}
\stoptext


which gives

• How I envy the ConTeXt interface! – Gonzalo Medina Apr 25 '13 at 4:38

Here is an approach which is somewhat more modular than alexurba's approach, which accomodates indefinite levels of nesting.

\makeatletter
\def\@enparen#1{\bgroup\let\enparen\@@enparen(#1)\egroup}
\def\@@enparen#1{\bgroup\let\enparen\@@@enparen[#1]\egroup}
\def\@@@enparen#1{\bgroup\let\enparen\@enparen\{#1\}\egroup}
\let\enparen\@enparen
\makeatother


Sample

\enparen{one \enparen{two \enparen{three \enparen{four} levels} levels} level}


Result

• Shouldn't the second \makeatletter be a \makeatother? If not, why not? – Pål GD Apr 25 '13 at 17:38
• @PålGD: yes indeed, fixed. – Niel de Beaudrap Apr 25 '13 at 17:39
• Nice one also. Cheers! – NVaughan Apr 25 '13 at 18:38

Maybe nested definitions:

\documentclass{article}

\newcommand{\enparent}[1]{{%
\def\enparent##1{{\def\enparent####1{\{####1\}}[##1]}}(#1)%
}}

\begin{document}

\noindent
\enparent{My outer layer \enparent{my inner lever \enparent{my innermost level}}}\\
\enparent{My outer layer \enparent{my inner lever \enparent{my innermost level}}}

\end{document}