Achieve consistent symbol height independently from subscript and superscript

Question

Consider the following:

\documentclass{minimal}
\usepackage{amsmath}
\begin{document}
    \fbox{\(+\)}, \fbox{{\(+_L\)}}, \fbox{{\(+^R\)}}, \fbox{{\(+^R_L\)}}
\end{document}

it produces:

As you can see, the surrounding box greatly changes in vertical size, and it produces a rather uncanny effect on one of my documents.

Is there any way to make all those boxes the same height (vertical size)?

Answer 1

You can add a \strut so most single line terms will fit:

\documentclass{minimal}
\usepackage{amsmath}
\begin{document}
    \fbox{\strut\(+\)}, \fbox{\strut\(+_L\)}, \fbox{\strut\(+^R\)}, \fbox{\strut\(+^R_L\)}
\end{document}