Form input of type image sends as parameters the x,y coordinates of
the point on the image where the click occurred. Param keys are
generally in the form, 'my_image.x' and 'my_image.y'. So, if one
wants to test whether a particular image coordinate key is present he
would typically use something like:
This results in a complaint that the 'x' method is not defined.
Presumably the problem is with the '.' in the symbol name. Enclosing
the key name in single quotes works; but, I think that has been
deprecated. I'm wondering what is the best way of handling this.
Thanks for any input.