I'm not sure whether it makes sense to have a physical "partially completed object". Would the ingredients of a reaction be consumed immediately or only on completion? Does it make sense to cancel a partial reaction?
Well, let's consider what baking bread would be like, once Toady gives the food system its intended overhaul.
1) Baker gathers all dry ingredients (flour, sugar, salt, optional flavorings*).
2) Baker gathers all perishable ingredients (milk, egg, yeast**, optional flavorings).
3) Baker mixes dry ingredients together.
4) Baker mixes in perishable ingredients.
5) Baker kneads the dough into a %cave wheat flour bread%.
6) The dough needs time to rise, the Baker won't be needed for an hour or so. During this time, he claims an Oven & loads it with charcoal (not coal).
7) Baker moves the %bread% into the Oven.
8 ) Baker sits & carefully watches the fire, to maintain its temperature***, as well as the bread once it's near to being done. Gains Wood Burner as well as Baker experience. If the Baker was smart (haha), he could multitask by Eating or Drinking during this step.
9) *«+cave wheat flour bread+»*
* Flavorings would count as decorations. Those that work well together, as well as with the nature of the base item (
e.g., cinnamon & raisins), would raise the decoration quality, those that don't (maple syrup & reindeer cheese) would lower it.
** Yeast does have a shelf life, albeit a quite long one. It could plausibly be moved to the dry list.
*** We humans are SO SPOILED to be able to just turn a knob & walk away.
Anyway, having a %bread% object makes it easier to move it from the Kitchen to the Oven, or between different areas of the kitchen if we're using Workshop Zones. I don't see any advantage if all this took place in a single Bakery workshop, as either the workshop
or the item could keep track of the time the dough has been rising / baking. [EDIT:] No, strike that. The advantage is that a good Baker will start a 2nd, 3rd, or 4th loaf while the 1st is rising. Rather than ask the Bakery workshop to keep track of all of their ages, each %bread% could just keep track of itself. Just as it wouldn't make sense for the Winery to keep track of the vintage of every single barrel of wine ever vinted there, we would write that on the barrels themselves. [/EDIT]
Reagents would be consumed as they are used: the dry ingredients would vanish from the workshop during step 3, the perishable ones in step 4, and I suppose the %cave wheat flour bread% reagent would first appear at the end of step 3. As for cancelling a partial reaction, it would only make sense
prior to step 4: That would either give you a dry %bread% mix to be used later & some perishable ingredients to put away, or all the ingredients & no mix. Cancelling at step 4 or later would mean tossing the whole mess into the garbage.
What would the relative advantages and disadvantages be over allowing reactions to pause and resume?
The real advantage comes when dealing with
multiple %items%, as with the Clothier above. By creating 15 %dresses% that can be stored in a nearby stockpile, the Clothier noticeably improves his turnaround time when the inevitable rush hits . . . while preventing his own skill rust during the slow season, and avoiding the lag caused by 14 suspended dress jobs cluttering up his workshop. With this example, the components of raw pig tail fabric would disappear just as the %pig tail dress% appears, and the construction of the dress could plausibly be cancelled at
any point and resumed later, with only a small delay as the Clothier (perhaps even a completely different Clothier) pieced the parts together & remembered (or figured out) just how much more of the process was left to be done.