Generate ND indexing functions on demand in JIT. * src/jit-typeinfo.cc (jit_operation::~jit_operation, jit_operation::do_generate, jit_operation::generate, jit_operation::signature_cmp::operator()): New function. (jit_operation::overload): Call do_generate when lookup fails. (jit_index_operation, jit_paren_subsref, jit_paren_subsasgn): New class. (jit_typeinfo::jit_typeinfo): Update to use jit_paren_subsref and jit_paren_subsasgn. (jit_typeinfo::gen_subsref, jit_typeinfo::gen_subsasgn): Removed functions. * src/jit-typeinfo.h (jit_operation::~jit_operation, jit_operation::generate, jit_operation::do_generate): New declaration. (jit_operation::add_overload, jit_operation::overload, jit_operation::result, jit_operation::to_idx): Use signature_vec typedef. (jit_operation::singature_cmp): New class. (jit_index_operation, jit_paren_subsref, jit_paren_subsasgn): New class. (jit_typeinfo::get_scalar_ptr): Nwe function. (jit_typeinfo::gen_subsref, jit_typeinfo::gen_subsasgn): Removed declaration. * src/pt-jit.cc: New test.

function p = subsasgn (p, s, val)
  if (length (s) < 1)
    error ("polynomial: needs index");
  endif
  switch (s(1).type)
    case "{}"
      ind = s(1).subs;
      if (numel (ind) != 1)
        error ("polynomial: need exactly one index");
      else
        if (length (s) == 1)
          if (isnumeric (ind{1}))
            p.poly(ind{1}+1) = val; 
          else
            p.poly(ind{1}) = val;
          endif
        else
          error ("polynomial: chained subscripts not allowed for {}");
        endif
      endif
    case "."
      fld = s(1).subs;
      if (strcmp (fld, "poly"))
        if (length (s) == 1)
          p.poly = val;
        else
          p.poly = subsasgn (p.poly, s(2:end), val);
        endif
      else
        error ("@polynomial/subsref: invalid property \"%s\"", fld);
      endif
    otherwise
      error ("invalid subscript type");
  endswitch
endfunction