Added special-case logical-indexing function * logical-index.h (New file) : Logical-indexing function. May be called on octave_value types via call_bool_index * nz-iterators.h : Add base-class nz_iterator for iterator types. Array has template bool for whether to internally store row-col or compute on the fly Add skip_ahead method which skips forward to the next nonzero after its argument Add flat_index for computing octave_idx_type index of current position (with assertion failure in the case of overflow) Move is_zero to separate file * ov-base-diag.cc, ov-base-mat.cc, ov-base-sparse.cc, ov-perm.cc (do_index_op): Add call to call_bool_index in logical-index.h * Array.h : Move forward-declaration for array_iterator to separate header file * dim-vector.cc (dim_max): Refers to idx-bounds.h (max_idx) * array-iter-decl.h (New file): Header file for forward declaration of array-iterator * direction.h : Add constants fdirc and bdirc to avoid having to reconstruct them * dv-utils.h, dv-utils.cc (New files) : Utility functions for querying and constructing dim-vectors * idx-bounds.h (New file) : Utility constants and functions for determining whether things will overflow the maximum allowed bounds * interp-idx.h (New function : to_flat_idx) : Converts row-col pair to linear index of octave_idx_type * is-zero.h (New file) : Function for determining whether an element is zero * logical-index.tst : Add tests for correct return-value dimensions and large sparse matrix behavior

## Copyright (C) 2006-2013 John W. Eaton
##
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or (at
## your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, see
## <http://www.gnu.org/licenses/>.

%!function y = f (x)
%!  global g;
%!  save_g = g;
%!  unwind_protect
%!    g = 0;
%!    y = g;
%!    [1,2;x];
%!    g = 1;
%!    y = [y, g];
%!  unwind_protect_cleanup
%!    g = save_g;
%!    y = [y, g];
%!  end  # "end" is part of test, check not using "end_unwind_protect"
%!endfunction
%!
%!test
%! global g = -1;
%! y = f ([3,4]);
%! assert (y, [0,1,-1]);

%!function y = f (x)
%!  global g;
%!  save_g = g;
%!  unwind_protect
%!    g = 0;
%!    y = g;
%!    [1,2;x];
%!    g = 1;
%!    y = [y, g];
%!  unwind_protect_cleanup
%!    g = save_g;
%!    y = [y, g];
%!    assert (y, [0,-1]);
%!  end_unwind_protect
%!endfunction
%!
%!test
%! global g = -1;
%! fail ("y = f (3);", "mismatch");