How to invoke two equally defined commands from different packages

Question

Assume we have two commands with the same name in different packages, like

inenglish.sty

\newcommand\house{This is a house.}

inspanish.sty

\newcommand\house{Esto es una casa.}

Can this macro be invoked differently from the calling document in a way that includes the package name?

If this is not possible, how can these two commands be grouped separately? The only way that comes to my mind is

\newcommand\houseinenglish{This is a house.}
\newcommand\houseinspanish{Esto es una casa.}

Answer 1

There are no namespaces in (La)TeX like in most programming languages. Following macro definitions will overwrite the previous ones (when defining macros with TeX's \def) or cause an error (when using LaTeX's \newcommand).

You can however copy the definition of one macro to another using \let\somenewmacro\someexistingmacro. The resulting macro is then independent from the other and does not use it later, like it would be the case when using \newcommand{\somenewcommand}{\someexistingmacro}.

In order to not cause error when the existing macro is defined again using \newcommand you can simply change its meaning to \relax so that \newcommand thinks it does not exists (as the does-already-exists check can not differ between a \relax and an undefined macro).

Basically try:

\usepackage{inenglish}
\let\houseinenglish\house
\let\house\relax % to 'undefine' it so that \newcommand\house works again 
\usepackage{inspanish}
\let\houseinspanish\house % or just use \house

Note that is is cumbersome if you have a lot of macros. Also if the macros uses further internal macros - also with the same names in both packages - you are in trouble.