Hello all,

I've been working on some code to do peek-ahead stuff in tables. It 
looks to me as though the \peek_...:NTF functions are broken in this 
context:

\documentclass{article}
\usepackage{array,expl3}
\begin{document}
\ExplSyntaxOn
\cs_new:Npn \CollectTokens {
   \peek_meaning:NTF \ignorespaces { } { }
}
\ExplSyntaxOff

\begin{tabular}{>{\CollectTokens}cc}
   a & \\
     & \\
       \\
\end{tabular}

\ExplSyntaxOn
\cs_set:Npn \CollectTokens {
   \cs_set_eq:NN \l_peek_search_token \ignorespaces
   \tl_set:Nn \l_peek_true_tl  { }
   \tl_set:Nn \l_peek_false_tl { }
   \peek_after:NN \peek_execute_branches_meaning:
}
\ExplSyntaxOff

\begin{tabular}{>{\CollectTokens}cc}
   a & \\
     & \\
       \\
\end{tabular}

\end{document}

The second version here omits the \group_align_safe_(begin/end): 
functions which the standard \peek_meaning:NTF, etc., functions add.

Any ideas what is up? Am I getting something wrong?
--
Joseph Wright