TikZ: conditional argument

Question

I have a macro that draw some objects, which takes as argument an optional parameter (left or right). To avoid repetitive code, I check for the input argument and condition TikZ parameter on that (left=of or right=of):

\newcommand{\mycommand}[1]{
    \ifthenelse{\equal{#1}{left}}{
        \def\side left
    }{
        \def\side right
    }
    \node (A) {$A$}
    \node (B) [\side=of A] {$B$};

I obtained the following error:

Use of \side doesn't match its definition.

Could you please help me to resolve this issue? Thank you very much in advance!

Answer 1

The (simplified) syntax of \def is \def\tokenname#1...{...}

\newcommand{\mycommand}[1]{
    \ifthenelse{\equal{#1}{left}}{
        \def\side{left}
    }{
        \def\side{right}
    }
    \node (A) {$A$}
    \node (B) [\side=of A] {$B$};