[Tex/LaTex] Enumeration problem redefining `enumerate` enivironment

Question

I would like to redefine the enumerate environment with an optional argument. Basically I want to redefine \theenumi so that each time I label an item and call it with \ref I get the real label printed, and not just the (arabic) value of counter enumi.

I tried with the code below, and it works except for the fact it always adds an extra point (.) to each label. When I call it with \ref it prints the correct label though.

Here is a MWE of what I tried:

\documentclass{book}
\usepackage{enumerate}
%%
%%
\let\oldenumerate\enumerate
\let\endoldenumerate\endenumerate
\renewenvironment{enumerate}[1][\arabic{enumi}.]% Defaults to 1. 2. 3. ...
{%
    \bgroup\renewcommand\theenumi{#1}%
    \oldenumerate%
}%
{%
    \endoldenumerate\egroup%
}%
\begin{document}
First list with default enumeration
\begin{enumerate}
\item First item
\item Second item
\end{enumerate}
Second list with custom enumeration
\begin{enumerate}[(\emph{\roman{enumi}})]
\item First item
\item Second item
\end{enumerate}
Labels have an extra dot in the lists, but references \ref{a} and \ref{b} are printed correctly.
\end{document}

and this is the output of the above code:

How should I redefine enumerate in order to avoid the extra dot in the lists?

Answer 1

Rather than reinventing the wheel, it's much easier to use the enumitem package for this sort of thing. For this particular example I've added a negative kern so that the parentheses are spaced nicely with the italic numeral. As Kannappan Sampath points out, you can specify the format of the references separately as well.

\documentclass{article}
\usepackage{enumitem}
\begin{document}
Second list with custom enumeration
\begin{enumerate}[label=(\kern-.5pt\emph{\roman*}),ref=(\roman*)]
\item First item \label{a}
\item Second item \label{b}
\end{enumerate}
Labels have an extra dot in the lists, but references \ref{a} and \ref{b} are printed correctly.
\end{document}