Pass a command as argument for another command

Question

Second question today: is there a way to pass a command as an argument of another method?

\newcommand\foo[1]{Foo does: `#1'}
\newcommand\bar[2]{Bar does: `#1{#2}'}

...

\bar{\foo}{xxx}

The output I want should be:

Bar does: `Foo does: `xxx''

Also, can someone explain to me what \expandafter does?

EDIT:

Sorry, for the question, after re-reading my code a few times, I noticed the origin of the mistake: the #1 in \bar was actually written \#1 instead. Nonetheless, thank you all for the quick answers.

Answer 1

The following works for me:

\documentclass{minimal}
\newcommand\Foo[1]{Foo does: `#1'}
\newcommand\BaBar[2]{BaBar does: `#1{#2}'}
\begin{document}
\BaBar{\Foo}{xxx}
\end{document}

perhaps you had an error \bar already defined? because I just copied your code and changed the name of the \bar command to avoid that error message.

Answer 2

In TeX there are no methods although you can define a macro in such a way as to be in many respects a method.

Consider the following minimal,

\documentclass{article}
\begin{document}
\long\def\aPieceOfCode{%
  This is a Piece of code that I need to type out in a number of ways.
  First pick the contents from the CMS and store it in macro. Then call them through your typesetter macros and hey it can even display maths \formula\ without the use of JavaScript!
}

\def\formula{$a=b^2+23 $}
\def\displayMyCode#1{#1}

\displayMyCode{\aPieceOfCode}
\end{document}

You can think of the \aPieceofCode as a function or object. In the displayMyCode macro you can pass this as an argument.