Product custom fields

-- HikaShop version -- : 2.5.0
-- Joomla version -- : 3.4.3

Hi,
with product characteristics, is it possible to do the following?

For the sale of cabinets of custom sizes, I need the user to be able to enter desired width value.
Once the user enters the width he desires, this width needs to be checked against min and max possible width for this product. Then given the desired width, a weight for the product is passed to the cart checked against range of widths. For example:
A cabinet can have width min 300mm and max 600mm.
A customers enters the value for the width he wants in the product page, lets say 450mm.
Now hikashop should check that it is within the min-max width allowed, and then calculate the weight of the product based on: for width 300-400 weight is 28kg, from 401-600 weight is 38kg.

I hope this makes sense.

Thanks for the reply,
so I create custom fields under Display->Custom Fields which will apply to a certain category. I will need to come up with the expression checks though. I mean, it will need to check against other product characteristics.
Is there any documentation on how to create these expressions?
Are there any examples on validation rules and writing expressions? This will help me as I have never done this before.
This is my first attempt at hikashop.
thanks

Thanks, this worked. Without the /
and I got an understanding of how these regex work.
Now I need to be able to get a price and weight value based on value entered in the custom field. So for example if the customer enters a value between 300-350 then the price will be "$300" and weight "28kg"
I created a new post in the forum for this.

Hi,

I need validation code for telephone field, it just should get digits and not alphabetic character. (I want enter this in Regular expression check field)/


Thanks