%token NUM = /(\d+)/
%token OP  = /([-+*\/])/

%{
my $nxs = 0;
%}

%conflict isInTheMiddle {

  $nxs++;

  if ($nxs == $self->YYVal('ExpList')) { 
    print "Reducing by :MIDx\n";
    $self->YYSetReduce(':MIDx' );
    
    $nxs = 0; 
  }
  else { $self->YYSetShift() } 
}  

%explorer isInTheMiddle 'ExpList'

%%

T: %isInTheMiddle? S
;

S:
     x  %PREC isInTheMiddle S x  
  |  %name :MIDx 
     x  %PREC isInTheMiddle 
;

x:
     NUM
  |  x OP NUM
;
%%

=head1 SYNOPSIS

This grammar is similar to the one in file C<nopackrat.eyp>.
It can't be parsed by LR(k) nor LL(k) algorithms.
Backtracking LR and GLR algorithms can but will perform poorly.

Compile it with:

   $ eyapp -P ExpList.eyp 
   $ eyapp -TC noPackratSolvedExpRGconcept.eyp

Run it with:

   $ ./noPackratSolvedExpRGconcept.pm -t -i -m 1 -c '2-3 3*4 5+2'

=head1 SEE ALSO

Files C<nopackrat.eyp>, C<noLRk_exp.eyp>, C<noLRk_expSolved.eyp>

=cut