Why aren't my trees working without line break?

Question

I am using the packages linguex, parsetree, and avm to make an example containing a table with two phrase structure trees. I'd like to have the table start on the same line as the example number. But when I begin the tabular environment without adding a line break, the trees aren't made.

Right line, trees don't work

Wrong line, trees work

What can I do to make the table start on the same line as the example?

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[]{linguex}
\usepackage[]{parsetree}
\usepackage[]{avm}

\begin{document}

\ex.
\begin{tabular}[t]{cc}
\begin{parsetree}
    (
    .\begin{avm}
        \[
        X \\
        Y
        \]
        \end{avm}.
    .\begin{avm}
        \[
        X \\
        Y
        \]
        \end{avm}.
    .\begin{avm}
        \[
        X \\
        Y
        \]
        \end{avm}.
    )
\end{parsetree}
&
\begin{parsetree}
    (
    .\begin{avm}
        \[
        X \\
        Y
        \]
        \end{avm}.
    .\begin{avm}
        \[
        X \\
        Y
        \]
        \end{avm}.
    .\begin{avm}
        \[
        X \\
        Y
        \]
        \end{avm}.
    )
\end{parsetree}
\end{tabular}

\end{document}

Answer 1

This is not a direct answer to your question, but a recommendation, perhaps. It will probably benefit you to switch to a more modern tree-drawing package. Two popular TikZ-based packages are tikz-qtree and forest, but there are, for example, pstricks options, too. Of the TikZ-based options, Forest is the most powerful and flexible.

Here's a Forest-based solution which uses a modified version of the avm style defined in my earlier answer to qtree - reduce spacing between lines in multiline node label with avm and a variant avm only.

avm only is intended only for trees where every node is simply an avm environment.

avm is intended for trees where some nodes contain no avm environment or contain content before the avm environment. In this case, the avm environment should be prefixed by a :, with any prior content before the :.

\documentclass{article}
\usepackage[linguistics]{forest}
\usepackage{avm,array,linguex}
\forestset{%
  avm/.style={%
    TeX={\setlength\extrarowheight{-10pt}},
    before typesetting nodes={%
      for tree={%
        split option={content}{:}{content,make avm},
      },
    },
  },
  avm only/.style={%
    TeX={\setlength\extrarowheight{-10pt}},
    before typesetting nodes={%
      for tree={%
        make pure avm,
      },
    },
  },
  make avm/.style={%
    if content={}{
      content=#1,
      make pure avm,
    }{
      content+={%
        \\\begin{avm}#1\end{avm}
      },
    },
  },
  make pure avm/.style={%
    content/.wrap value={%
      \begin{avm}##1\end{avm}
    },
    plain content,
  },
}
\begin{document}
\ex.
\begin{forest}
  avm,
  [:\[X\\Y\]
    [:\[X\\Y\]
    ]
    [:\[X\\Y\]
    ]
  ]
\end{forest}
\begin{forest}
  avm only,
  [\[X\\Y\]
    [\[X\\Y\]
    ]
    [\[X\\Y\]
    ]
  ]
\end{forest}

\end{document}

Answer 2

I found that I was also able to get the right result by keeping parsetree and switching out linguex with gb4e.