onlyitems.sty

% A package that allows the selection of items from a list based on
% the id's of the items in the list (good for CV's) based on an answer
% by Ryan Reich on TeX.SE
% http://tex.stackexchange.com/questions/4502/onlyitems-how-to-select-specific-items-from-an-item-list/32611#32611 


%%%%%%%%%%%%%%%%%
\ProvidesPackage{onlyitems}

\RequirePackage{pgfkeys}
\RequirePackage{pgffor}



% A huge list of pgfkeys to be set up.  
\pgfkeys{
 /onlyitems/.is family, /onlyitems,
 % Utility keys
 utility/store tag/.store in = \itemOptions,
 utility/store bool/.store in = \itemIf,
 utility/process true/.style = {process/#1 = \iftrue},
 utility/process false/.style = {process/#1 = \iffalse},%\fi
 utility/set store bool/.style 2 args = {#1/.style = {utility/store bool = #2}},
 utility/set select style/.style 2 args = {utility/set store bool = {select/#1}{#2}},
 utility/verdict/.style = {},
 utility/add to reset/.style = {
  reset/.prefix style = {select/#1/.style = {select/.unknown}}
 },
 utility/current key/.estore in = \itemKey,
 % Nothing in the process family is ever set, so any selection option is set to store a boolean
 process/.unknown/.style = {
  utility/current key = \pgfkeyscurrentname,
  select/\itemKey/.style = {
   utility/set store bool = {utility/verdict}{#1}
  },
  utility/add to reset/.expand once = \itemKey
 },
 % For clearing the list of selected items (to support nested {itemize})
 reset/.style = {},
 reset/reset/.style = {reset/.style = {reset/reset, default}},
 reset/reset,
 % Here are the options you can actually pass.  These go to the {itemize}...
 include/.style = {utility/process true/.list  = {#1}},
 exclude/.style = {utility/process false/.list = {#1}},
 all/.style  = {utility/set select style = {.unknown}{\iftrue}},
 none/.style = {utility/set select style = {.unknown}{\iffalse}},%\fi
 default/.style = {all},
 % ...and these to the \item's
 tag/.style = {utility/store tag = {[#1]}},
 id/.style = {select/#1}, 
%yossi
.unknown/.style = {tag=\pgfkeyscurrentname} %if key is
%.unknown/.code = \onlyitemsset{utility/store tag=\pgfkeyscurrentname} %if key is
                                %unknown, treat it like a tag. thanks
                                %to Andrew Stacy: \url{http://tex.stackexchange.com/q/34376/86}
%end yossi
}

% Like tikzset, it sets a default key path
\newcommand\onlyitemsset[1]{\pgfkeys{/onlyitems, #1}}

\makeatletter

\let\itemLaTeX=\item
% Have to use a \newcount because (ugh) the LaTeX \setcounter is a global assignment
\newcount\itemsSoFar
\newcommand\onlyitemsItem[1][]{%
 % The \egroup closes off any \vbox'es from the previously ignored \item.
 % The conditional \bgroup cancels it out when there aren't any.
 \itemIf\bgroup\fi\egroup
 \let\itemIf=\iffalse%\fi
 \advance\itemsSoFar by 1 %
 \onlyitemsset{utility/store tag = {}, utility/verdict/.style = {}, select/\the\itemsSoFar, #1, utility/verdict}%
 \itemIf
  \def\next{\expandafter\itemLaTeX\itemOptions}%
 \else
  % The vbox is set and then discarded, effectively ignoring an entire \item.
  % This inner \itemLaTeX is necessary to avoid a glitch when we
  % ignore the first \item of an itemize that itself contains a nested
  % \itemize.  Don't ask, I don't know.
%
%the \@gobble s are so that various numerated lists still work as if
%the items are missing (i.e, no side effects). reference: http://tex.stackexchange.com/questions/34811/how-to-skip-an-item-entirely-with-no-side-effects/34821#34821
  \def\next{\setbox0=\vbox\bgroup\let\stepcounter=\@gobble\let\addtocounter\@gobbletwo\itemLaTeX}%
 \fi
 \next
}
\makeatother

\newcommand\onlyitems[2][]{%
\let\item=\onlyitemsItem
 \let\itemIf=\iftrue
 \itemsSoFar = 0 %
 % We have to reset here so that the selections from an outer itemize don't conflict with an inner one.
 \onlyitemsset{reset, #1}%
 #2%
 % This closes off the last \vbox
 \itemIf\bgroup\fi\egroup
}