gb4e modified to be left-aligned with examples indented 0.5in, as required by the NELS style guide. Use at your own risk!

gb4e-nels.sty

% -*- LaTeX -*-
\def\gbVersion{4e}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%  Version 4export (= v. 4 minus the compatibility code)
%  Based on hpk's gb.sty, revised for GM syllabus by ct,
%  and incorporating macros adapted from J.Frampton, M. van der Goot en M.
%  Covington. Full documentation in gb4e-doc.tex. Bug-reports
%  and suggestions for improvements, other used features, please!
%
%  The package gb4e may be distributed under the conditions of the LaTeX Project
%  Public License (LPPL). See the README file for more details.
%
%  Notes:
%  
%  Various styles for X-bar levels; can be changed, but note that {picture}
%  environements (e.g. trees) will then come out wrong and have to be
%  fixed
%
%  This file allows _ and ^ to be used in ordinary text, hence must be
%  loaded AFTER any file that uses them in their TeX meaning. Hence
%  cgloss(n).sty is loaded early in this file.  This feature is known to
%  cause some problems with other packages, but is maintained for backward 
%  compatibility. If you have problems, you can try disabling it by
%  placing the command \noautomath immediately after loading the gb4e package.
%  [Added 2009/12/28]

% CHANGE LOG
%
% 2010/7/2
%    - Fixed bug (introduced in previous changes) that discarded spaces 
%    after sub/superscripts outside math mode. 
%
% 2010/01/03 [unreleased]
%    - Removed stray \bf
%    - Removed leftover old definition of ^, _
%
% 2009/12/28 
%                   - Added README.txt with LPPL license statement.
%    - Updated sub- and superscripts outside of math mode. They now 
%    combine properly, and the feature can be turned off with \noautomath 
%    (and back on with \automath).
%    - Removed references to \rm, for compatibility with memoir.cls
%    - \@footnotetext is no longer modified destructively; compatible with
%    other packages that modify it.
%    - \eachwordone etc. can now be defined to font commands that take
%    arguments (e.g., to \textit).
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%
%  Format of examples: %
%%%%%%%%%%%%%%%%%%%%%%%%
% \begin{exe} or \exbegin
% <examples>                           (arab.)
% \begin{xlist} or \xlist
% <subexamples>                        (1st embedding, alph.)
% \begin{xlisti} or \xlisti
% <subsubexamples>                     (2st embedding, rom.)
% \end{xlisti}  or \endxlisti
% <more examples>
% \end{xlist} or \endxlist
% <still more examples>
% \end{exe} or \exend
%
% Other sublist-styles: xlistA (Alph.), xlistI (Rom.), xlistn (arab)
%
% \ex                               (produces Number)
% \ex <sentence>                    (numbered example)
% \ex[jdgmt]{sentence}              (numbered example with judgement)
%
% \exi{ident}                      (produces identifier)
% \exi{ident} <sentence>           (example numbered with identifier)
% \exi{ident}[jdgmt]{sentence}     (dito with judgement)
%                      (\exr, \exp and \sn are defined in terms of \exi)
%
% \exr{label}                       (produces cross-referenced Num.)
% \exr{label} <sentence>            (cross-referenced example)
% \exr{label}[jdgmt]{sentence}      (cross-referenced example with judgement)
%
% \exp{label}                       (same as
% \exp{label} <sentence>                     \exr but
% \exp{label}[jdgmt]{sentence}                        with prime)
%
% \sn <sentence>                    (unnumbered example)
% \sn[jdgmt]{sentence}              (unnumbered example with judgement)
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% For my own laziness (HANDLE WITH CARE---this works only
%                                 in boringly normal cases.... ):
%
% \ea                works like \begin{exe}\ex or \begin{xlist}\ex,
%                            depending on context
% \z                 works like \end{exe} or \end{xlist}, dep on context
% 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% For any REALLY old distributions without \rmfamily
\@ifundefined{rmfamily}{\let\rmfamily=\rm \let\bfseries=\bf}

\@ifundefined{new@fontshape}{\def\reset@font{}\let\mathrm\rmfamily\let\mathit\mit}{}

\let\prmbrs=0
\def\primebars{\let\prmbrs=1}
\def\obar#1{\ifmmode#1^{0}\else#1$^{0}$\fi}  %% FIX
\def\mbar#1{\ifmmode#1^{\mathrm{max}}\else#1$^{\mathrm{max}}$\fi}
\def\ibar#1{\ifx\prmbrs0%
                 \ifmmode\overline{\mathrm{#1}}\else$\overline{\mbox{#1}}$\fi%
            \else\ifmmode#1^{'}\else#1$^{'}$\fi\fi}
\def\iibar#1{\ifx\prmbrs0%
                  \ifmmode\overline{\overline{\mathrm{#1}}}%
                  \else$\overline{\overline{\mbox{#1}}}$\fi%
             \else #1P\fi}
\def\th{\ifmmode\theta\else$\theta$\fi}
\def\al{\ifmmode\alpha\else$\alpha$\fi}
\def\be{\ifmmode\beta\else$\beta$\fi}
\def\ga{\ifmmode\gamma\else$\gamma$\fi}
\def\de{\ifmmode\delta\else$\delta$\fi}
\def\spec#1{[Spec,#1]} %Def. of "Specifier of #1"
\def\ct#1{{\em #1\/}} %Citation of linguistic material with alternative style:
%\def\ct#1{`#1'}
\def\tx{\bfseries} %Introduction of technical terms with alternative style:
%\def\tx{\em}

\input{cgloss\gbVersion.sty}

\newcommand{\indexgroupmark}[1]{\item{\bfseries #1}}  % ?? -CT


%%%%%%%%%%% AUTOMATH 

% this allows _ to be used in horizontal mode (from J.Frampton):
% Reimplemented to allow this feature to be turned on and off.
% The new version also combines sub- and superscripts properly.
% -Alexis

% \automath     Make _ and ^ work outside math mode
% \noautomath   Restore normal sub/superscript behavior

{ % Temporarily change catcodes
  \catcode`\_=\active
  \catcode`\^=\active

  \global\def\automath{%
    \catcode`\_=\active
    \catcode`\^=\active
    \def_##1{\gb@ifnextchar^{\automath@two_{##1}}{\ensuremath{\sb{##1}}}}%
    \def^##1{\gb@ifnextchar_{\automath@two^{##1}}{\ensuremath{\sp{##1}}}}}
}
\def\automath@two#1#2#3#4{\ensuremath{#1{#2}\relax #3{#4}}}
% Restore default catcodes for ^, _
\def\noautomath{\catcode`\_=8 \catcode`\^=7 }

% The original \@ifnextchar discards spaces when looking for the next
% ``character''. This variant accepts any token.
\long\def\gb@ifnextchar#1#2#3{%
  \let\reserved@d=#1%
  \def\reserved@a{#2}%
  \def\reserved@b{#3}%
  \futurelet\@let@token\@gbifnch}
\def\@gbifnch{%
    \ifx\@let@token\reserved@d
      \let\reserved@c\reserved@a
    \else
      \let\reserved@c\reserved@b
    \fi
  \reserved@c}

\automath % On by default, for backward compatibility

%%%%%%%%%


\def\lb#1{\@ifnextchar [{\@glarph{#1}}{\@bl{#1}}}
\def\@glarph#1[#2]{\ifmmode{[}\sb{{\mathrm{#1}}\sb{#2}}\else%
                           ${[}\sb{{\mathrm{#1}}\sb{#2}}$\fi}
\def\@bl#1{\ifmmode{[}\sb{\mathrm{#1}}\;\else${[}\sb{\mathrm{#1}}\;$\fi}

\def\rb#1{\@ifnextchar [{\@grarph{#1}}{\@br{#1}}}
\def\@grarph#1[#2]{\ifmmode{]}\sb{{\mathrm{#1}}\sb{#2}}\else%
                        ${]}\sb{{\mathrm{#1}}\sb{#2}}$\fi}
\def\@br#1{\ifmmode{]}\sb{\mathrm{#1}}\;\else${]}\sb{\mathrm{#1}}\;$\fi}

%%% END_NEWSTUFF.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%  Macros for examples, roughly following Linguistic Inquiry style.   %
%  From here on best not to tamper, else all the examples and cross-  %
%  references will come out scrambled! (see also note below) - CT     %
%  Completely rewritten for more robustness and flexibility. (hpk)    %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\def\qlist{\begin{list}{\Alph{xnum}.}{\usecounter{xnum}%
\setlength{\rightmargin}{\leftmargin}}}
\def\endqlist{\end{list}}

\newif\if@noftnote\@noftnotetrue
\newif\if@xrec\@xrecfalse
\@definecounter{fnx}

%%%%% Get examples in footnotes right
% Replaces code in original gb4e.sty: changed 2009/12/28 by Alexis
% Same function as before, but the old version interacted poorly with
% other packages that redefine \@footnotetext.

\let\@gbsaved@footnotetext=\@footnotetext
\long\def\@footnotetext#1{%
    \@noftnotefalse\setcounter{fnx}{0}%
    \@gbsaved@footnotetext{#1}%
    \@noftnotetrue}

\newcount\@xnumdepth \@xnumdepth = 0

\@definecounter{xnumi}
\@definecounter{xnumii}
\@definecounter{xnumiii}
\@definecounter{xnumiv}
\@definecounter{exx}
\setcounter{exx}{0}
\def\thexnumi{\@xsi{xnumi}}
\def\thexnumii{\@xsii{xnumii}}
\def\thexnumiii{\@xsiii{xnumiii}}
\def\thexnumiv{\@xsiv{xnumiv}}
\def\p@xnumii{\thexnumi}
\def\p@xnumiii{\thexnumi\thexnumii-}
\def\p@xnumiv{\thexnumi\thexnumii-\thexnumiii-}

\def\xs@default#1{\csname @@xs#1\endcsname}
\def\@@xsi{\let\@xsi\arabic}
\def\@@xsii{\let\@xsii\alph}
\def\@@xsiii{\let\@xsiii\roman}
\def\@@xsiv{\let\@xsi\arabic}

\@definecounter{rxnumi}
\@definecounter{rxnumii}
\@definecounter{rxnumiii}
\@definecounter{rxnumiv}

\def\save@counters{%
\setcounter{rxnumi}{\value{xnumi}}%
\setcounter{rxnumii}{\value{xnumii}}%
\setcounter{rxnumiii}{\value{xnumiii}}%
\setcounter{rxnumiv}{\value{xnumiv}}}%


\def\reset@counters{%
\setcounter{xnumi}{\value{rxnumi}}%
\setcounter{xnumii}{\value{rxnumii}}%
\setcounter{xnumiii}{\value{rxnumiii}}%
\setcounter{xnumiv}{\value{rxnumiv}}}%


\def\exewidth#1{\def\@exwidth{#1}} \exewidth{(234)}
\def\exe{\@ifnextchar [{\@exe}{\@exe[\@exwidth]}}

\def\@exe[#1]{\ifnum \@xnumdepth >0%
                 \if@xrec\@exrecwarn\fi%
                 \if@noftnote\@exrecwarn\fi%
                 \@xnumdepth0\@listdepth0\@xrectrue%
                 \save@counters%
              \fi%
                 \advance\@xnumdepth \@ne \@@xsi%
                 % hbox added here - mitcho for NELS:
                 \begin{list}{\hbox to 0.3in{(\thexnumi)}}%
                             {\usecounter{xnumi}\@subex{0.3in}{0.5in}%
                              \if@noftnote%
                                 \setcounter{xnumi}{\value{exx}}%
                              \else%
                                 \setcounter{xnumi}{\value{fnx}}%
                              \fi}}

\def\endexe{\if@noftnote\setcounter{exx}{\value{xnumi}}%
                   \else\setcounter{fnx}{\value{xnumi}}%
                        \reset@counters\@xrecfalse\fi\end{list}}

\def\@exrecwarn{\typeout{*** Recursion on "exe"---your
                example numbering will probably be screwed up!}}

\def\xlist{\@ifnextchar [{\@xlist{}}{\@xlist{}[iv.]}}
\def\xlista{\@ifnextchar [{\@xlist{\alph}}{\@xlist{\alph}[m.]}}
\def\xlisti{\@ifnextchar [{\@xlist{\roman}}{\@xlist{\roman}[iv.]}}
\def\xlistn{\@ifnextchar [{\@xlist{\arabic}}{\@xlist{\arabic}[9.]}}
\def\xlistA{\@ifnextchar [{\@xlist{\Alph}}{\@xlist{\Alph}[M.]}}
\def\xlistI{\@ifnextchar [{\@xlist{\Roman}}{\@xlist{\Roman}[IV.]}}

\def\endxlist{\end{list}}
\def\endxlista{\end{list}}
\def\endxlistn{\end{list}}
\def\endxlistA{\end{list}}
\def\endxlistI{\end{list}}
\def\endxlisti{\end{list}}


%%% a generic sublist-styler
\def\@xlist#1[#2]{\ifnum \@xnumdepth >3 \@toodeep\else%
    \advance\@xnumdepth \@ne%
    \edef\@xnumctr{xnum\romannumeral\the\@xnumdepth}%
    \def\@bla{#1}
    \ifx\@bla\empty\xs@default{\romannumeral\the\@xnumdepth}\else%
      \expandafter\let\csname @xs\romannumeral\the\@xnumdepth\endcsname#1\fi
	% hbox added here - mitcho for NELS:
    \begin{list}{\hbox to 0.3in{\csname the\@xnumctr\endcsname.}}%
                {\usecounter{\@xnumctr}\@subex{0.3in}{0.4in}}\fi}

% subex has been completely redefined - mitcho for NELS:
\newlength{\reallabelwidth}
% #1 = width of the label area, #2 = width from the left
\def\@subex#1#2{%
		\leftmargin=#2%
		\labelwidth=2em%
		%\labelwidth=\reallabelwidth%
		\itemindent-0pt%
		\labelsep=#2%
		\advance\labelsep by -#1% subtract the real width of the label.
		\ifnum\the\@xnumdepth=1%
			% 1em between exx
			\topsep=0.6em%
			\itemsep=1em%
		\else%
			% 0.5em between subexx
			\topsep=0.3em%
			\itemsep=0.5em%
		\fi%
		\parsep\p@ plus.5\p@ minus.5\p@%
		\relax}

%%% the example-items
\def\ex{\@ifnextchar [{\@ex}{\item}}
\def\@ex[#1]#2{\item\@exj[#1]{#2}}
\def\@exj[#1]#2{\@exjbg{#1} #2 \end{list}}
\def\exi#1{\item[#1]\@ifnextchar [{\@exj}{}}
% @exjbg rewritten - mitcho for NELS:
\def\@exjbg#1{\begin{list}{#1}{\@subex{-0.3em}{0in}}\item}
\def\exr#1{\exi{{(\ref{#1})}}}
\def\exp#1{\exi{{(\ref{#1}$'$)}}}
\def\sn{\exi{}}
\def\bu{\item[$\bullet$]}

%%% Lazy abbrevs (HANDLE WITH CARE!)
\def\ea{\ifnum\@xnumdepth=0\begin{exe}[(234)]\else\begin{xlist}[iv.]\fi\ex}
\def\z{\ifnum\@xnumdepth=1\end{exe}\else\end{xlist}\fi}


%%%%%%% \lcomment for breaks in (example-)lists (leaves all counters
%%%%%%% as they are)    (hpk) 
\newlength{\lcommentsep}
\lcommentsep = 1ex

\long\def\lcomment#1%
   {\vspace{\lcommentsep}
    \item[]\hspace*{-\leftmargin}%
    \@tempskipa=\linewidth%
    \addtolength{\@tempskipa}{\rightmargin}%
    \addtolength{\@tempskipa}{\leftmargin}%
    \parbox{\@tempskipa}{#1}%
    \vspace{\lcommentsep}%
   }

%%%%%% control the alignment of exampleno. and (picture-)example
%%%%%%         (by Lex Holt <lex@cogsci.ed.ac.uk>).
\def\attop#1{\leavevmode\vtop{\strut\vskip-\baselineskip\vbox{#1}}}
\def\atcenter#1{$\vcenter{#1}$}
%%%%%%

%-------------------Move Arrows (from J.Frampton):

\def\leaderfill{\leaders\hrule\hfil}
\def\pointerup{\hbox to 0pt{\hss
  \vbox{\offinterlineskip\vskip-1pt\hbox{\elevenex\char'170}\null}\hss}}
\def\pointerdown{\hbox to 0pt{\hss
  \vtop{\offinterlineskip\null\hbox{\elevenex\char'171}\vskip-1pt}\hss}}

\let\pu=\pointerup
\let\pd=\pointerdown
\let\lf=\leaderfill

\def\spacer{\hskip4.5pt}
\def\fillright#1{\hfil#1\leaderfill}
\def\fillleft#1{\leaderfill#1\hfil}
% Changed spelling to \centr, else conflicts with LaTeX \center{} -CT
\def\centr#1{\leaderfill#1\leaderfill}
\def\link#1{\multispan#1\leaderfill}

\def\arrowalign#1{\vtop{\baselineskip=0pt \lineskiplimit=0pt \lineskip=2pt
  \halign{&##\cr#1}}}

\font\elevenex=cmex10 scaled\magstephalf  % just for the arrow!
      %PS: this may not work on some installations, not sure why. CT
      %%PPS: (e.g., PCTeX, but it works find works fine with EmTeX)
%----------------END Move Arrows

\def\pijl{$\rightarrow$\ }

% Special accents for Vata & Gbadi; Navajo coming soon, I hope...:
%\def\bb#1{$\mathrm{\overline{#1}}$} Following looks better:
\def\bb#1{\ifmmode\overline{\mathrm{#1}}\else$\bar{\mathrm{#1}}$\fi}

\def\boven#1#2{\raisebox{-0.2pt}{$\stackrel{#1}{\mathrm{#2}}$}}
\def\bovenop#1#2{\raisebox{-0.06ex}[0ex][0ex]{$\stackrel{#1}{\mathrm{#2}}$}}
\def\vl{\rule{0.05em}{0.30em}}
\def\|#1{\ifmmode\vert#1\else\bovenop{\vl}{#1}\fi}