New environment in latex using other environments, compiler doesn't find the \end

Question

I'm setting up a new environment for my latex document for consistent tables. It looks like this:

\newenvironment{defaultTable}[2] {
    \begin{table}[h]
    \noindent
    \tabularx{\textwidth}{#1}
    \specialrule{0.5pt}{10pt}{0pt} \rowcolor[gray]{.9}
} {
    \bottomrule 
    \endtabularx
    \caption{#2}
    \end{table}
}

It doesn't seem to find the \end{table} though:

! LaTeX Error: \begin{table} on input line 23 ended by \end{document}.

Is there a way to avoid this?

Answer 1

You can not use #2 in the last argument of the \newenvironment macros. You should use #1..#9 in the second argument only.

Save your #2 to \tempa (or any macros). And use \tempa in the caption.

\newenvironment{defaultTable}[2]{
  \begin{table}[h]
  \def\tempa{#2}
  \noindent    
  \tabularx{\textwidth}{#1}    \specialrule{0.5pt}{10pt}{0pt} \rowcolor[gray]{.9}
}{    
 \bottomrule     
 \endtabularx    
 \caption{\tempa}
 \end{table}
}

Answer 2

You can use #2 in the end if you use the xparse mechanism:

\usepackage{xparse}
\NewDocumentEnvironment{defaultTable}{+m+m}{%
    \begin{table}[h]
    \noindent
    \tabularx{\textwidth}{#1}
    \specialrule{0.5pt}{10pt}{0pt} \rowcolor[gray]{.9}
} {%
    \bottomrule 
    \endtabularx
    \caption{#2}
    \end{table}
}

Answer 3

Replace \begin{table} with \@float{table} and replace \end{table} with \end@float.

The \@float and \end@float are LaTeX's internal commands for starting and ending the float environment.

You'll also want to follow Alexey's advice on the #2 parameter. Store it in the first part of your environment (\gdef\mycaption{#2}) and then recall it later \caption{\mycaption} in the second part. Put \def\mycaption{\relax} just before the \begin{defaultTable} line.

Also, since \@float and \end@float have @ signs in them, if this code is in the preamble of your document file (instead of say, a .sty file), you'll need to put \makeatletter before your \begin{defaultTable} and also \makeatother after \end{defaultTable}.