ALBANY – A would-be purchaser of real estate who breaches his contract should be subject to damages equivalent to the difference, if any, between the value of the property when the contract was signed and when it was breached, the state Court of Appeals ruled yesterday.

The court said in White v. Farrell, 43, that its decision represented the first time it has ever considered the measure of damages for a purchaser’s breach of the contract for real property.