>>>Actually, then I heard from someone, in a discussion on the subject, that the most complicated and largest contraption in use, an ocean liner, didn't go deeper than ten levels.
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>>Last statement is interesting. Of course, once you go beyond one level the only approach that makes sense is a self-referencing/recursive one.
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>>The one I worked on was basically for recipes (i.e. food). There were ~1000 ingredients from which recipes were built. More than five levels were quite common. Also fractions of a recipe as well as multiples were allowed. e.g based on Bread:
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>Amazing... same happened to me. I ported that assembly line app to serve a restaurant :). The same principle, with proportional costing if a subrecipe was included in quantity different from 1 - if, say, a standard salad was served on the main dish, it would go as half, whereas as a whole if served as a side dish, etc.
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>As a curiosity, I also had to write the bar side of the restaurant app, with daily inventory by the bottle and how much should remain in a started bottle. If one bottle of vinjak (Yugoslav variant of cognac) holds 1l, that is 20 shots per 0,05 l - so if they served 12, there should be 0,4l left in the bottle. Goes (somewhere) to show how much the owner trusted his waiters :).

And with good reason. It's a fact of life in the restaurant business that your employees will slip the food and drink you have paid for to their friends etc. Bartenders are notorious offenders, often for the mundane reason of generating better tips. Which of course go straight into their pocket. I'm not saying this makes them horrible people, it's just a fact of life when you own a restaurant. Smart owners look the other way as long as it isn't too outrageous and the employee is doing the job otherwise. Good bartenders and good waitresses draw loyal repeat business and you can't put a value on that.