StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>First, there's not really enough detail here to form an opinion, so I'm left to guess. You've provided a challenging question and a minimal solution, but not clarified what is wrong with your solution.</p> <p>I suspect the complaint centers around the reset back to knowing nothing between a refused construction and the following construction attempts. Given a very large number of potential factories this reset could have us parsing the same data hundreds or thousands of times. If this is the problem the question is this: how do you structure the predicate evaluation phase to limit the amount of work, and allow it to reuse previous parsing results.</p> <p>I suggest having each factory register with: 1) a factory builder function taking the specialization parameter(s) (iostream in the example) 2) an unordered set of boolean predicates 3) required boolean values of each predicate to allow construction</p> <p>The set of predicates is used to create/modify the predicate tree. Interior nodes in the tree represent predicates (branching to 'pass', 'fail', and possibly 'don't care'). Both interior nodes and leaves hold constructors which are satisfied if the ancestral predicates are satisfied. As you traverse the tree you first look for constructors at the current level, then evaluate the predicate and follow the required path. If no solution is found along that child path the follow the 'don't care' path.</p> <p>This allows new factories to share predicate functions. There's probably lots of questions about managing/sorting the tree when the factories go on/off line. There's also the possibility of parser state data that needs to be retained across predicates and reset when construction is completed. There's lots of open questions, but this may work toward addressing the perceived problems with your solution.</p> <p><strong>TL:DR;</strong> Create a graph of predicates to traverse when attempting construction.</p>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload