class _special_cleft_extraction 
{
    %% some cleft constructions remove the main verbs
    %% example: c'est lui le chef
    %% standing for "c'est lui qui est le chef"
    %% example: c'est le chat le coupable
    %% Also work for reversed construction
    %% example: le chef, c'est lui.
    %% Also work with infinitive sentence
    %% example: dormir, c'est mourir un peu
    %% desc.ht = value([arg0: @emptyarg_fs,arg1: @emptyarg_fs,arg2: @emptyarg_fs]);
    %% S >> N2;
    node S : [cat: S, id: S, bot: [sat: -]];
    node(S).top.extraction = value(-);
    node(S).bot.extraction = value(cleft|wh|adjx);
    node(S).bot.gender = node(S).top.gender;
    node(S).bot.number = node(S).top.number;
    node(S).bot.person = node(S).top.person;
    node(S).bot.mode = node(S).top.mode;
    node(S).bot.tense = node(S).top.tense;
    node(S).bot.neg = node(S).top.neg;
%    node(S).bot.wh = node(S).top.wh;
%    node(S).bot.inv = node(S).top.inv;
    node N1: [type: alternative];
    N1 >> N1N;
    N1 >> N1S;
    N1N < N1S;
    node N2: [type: alternative];
    N2 >> N2N;
    N2 >> N2S;
    N2 >> N2Adj;
    N2N < N2S;
    N2S < N2Adj;
    node N1N: [cat: N2, id: subject, type: subst, top:[ sat: + ]];
    node N2N: [cat: N2, id: comp, type: subst, top:[ sat: + ]];
    node N1S: [cat: S, id: subject, type: subst, top:[ sat: - ]];
    node N2S: [cat: S, id: comp, type: subst, top:[ mode: infinitive, extraction: -, sat: - ]];
    node N2Adj: [cat: adjP, id: comp, type: subst];
    /*
    %% difficult to set strict constraints
    N2N +
        node(N1N).top.person = node(N2N).top.person,
        node(N1N).top.gender = node(N2N).top.gender,
        (
            node(N1N).top.number = node(N2N).top.number
            |
            node(N1N).top.number = value(pl),
            node(N1N).top.person = value(2),
            node(N2N).top.number = value(sg)
         );
    */
}