Can I do without "eval" here?

["Com MN PG P E B Consultant 3" <mn-pg-p-e-b-consultant-3.com@siemens.com>]

Maybe just a matter of style, but here is a (simplified) version of a
problem which
I have solved, but where I am not satisfied with the solution ...

Assume I have a command CMD which can be called in the following ways:

  CMD -x FILENAME
  CMD -y 'this is some string with alphanumerics and spaces' FILENAME

I call this CMD from a skript MYSCRIPT. If the skript is called with 1
parameter, I use the second form and put the
parameter into the argument of my -y option. If MYSCRIPT is called
without parameters, I use the -x option.
For sake of simplicity, we can assume that the FILENAME is always
hardcoded. That is, if someone calls
MYSCRIPT without any arguments, i.e.

  MYSCRIPT

it should execute

  CMD -x foo

But if MYSCRIPT is called like this:

  MYSCRIPT "bar baz"

it should execute 

  CMD -y 'bar baz' foo

Here is my solution (which I ask you to improve):

#!/bin/zsh
if [[ $# -eq 0 ]]
then
  options=-x
else
  options="-y '$1'"
fi
eval CMD $options foo

The 'eval' is necessary here, because if I write just

   CMD $options foo

CMD would see for example -y 'bar baz' as first argument, and not just
-y.

What I don't like in this example, is the usage of eval. Although it is
harmless in this particular case,
the filename 'foo', which is hardcoded here, comes in as a parameter too
in my real application, and 
this means that it undergoes one level of evaluation too, which would
yield wrong results when it contains,
say, a $ character. 

Of course one might argued that when you are thinking of filenames with
$, you are doomed anyway, but 
still I'm not a big fan of using 'eval' anyway, so I wonder whether this
can be done without eval
too....

Ronald