pan class='op'>*</span> <span class='va'>x</span>, <span class='kw'>function</span><span class='op'>(</span><span class='op'>)</span> <span class='va'>x</span><span class='op'>)</span>

<span class='co'># using tf_cond() wrapper</span>
<span class='va'>tilde</span> <span class='op'>&lt;-</span> <span class='kw'>function</span><span class='op'>(</span><span class='va'>x</span><span class='op'>)</span> <span class='fu'>tf_cond</span><span class='op'>(</span><span class='va'>x</span> <span class='op'>&gt;</spa