Long formulas

Even with the mechanisms offered by OAK to tame fan-out, the formulas that result from OAK can become very long.

Sometimes they get so long that they pass the limit that Excel is capable of handling.
(1024 characters in Excel 2003, 8192 characters in Excel 2007)

In such cases OAK places a single quote in front of the result of a reconstruction, so that Excel will treat it as a text constant rather than a formula.  But the formula is still real, in the sense that it would work if the quote was removed and Excel could handle the formula.  This is easy to demonstrate: Excel 2007's limit on the length of a formula is higher than earlier versions of Excel, so it can be used to test reconstructions too long for Excel 2003.

A formula that is very long would be of questionable value in a real model.  In fact, we have emphasized that the style of Operis, and of well-trained analysts elsewhere, is to build calculations up in simple steps using a number of short formulas.  But the purpose of a reconstruction is not to produce shippable code to paying customers.  A reconstruction rapidly produces an abstract from a larger model, which stands a chance of shedding insight into what a particular calculation does and how it goes about it.  They are disposable: the majority of reconstructions are thrown away a few minutes after they are generated.