NSFetchRequest+Explain allows to debug NSFetchRequests and NSPredicates in visual way.

• Treelike description with pretty printing
• Easy to use (just call explainXY on any result or object you like)
• Easy to find problems
  • Can be used to identify objects not found by the fetchrequest
  • Find hot spots (parts of the predicate that create the most misses)
  • just better visualisation as the default description
  • Shows actual values not just miss or match
• Find errors in the predicate (e.g. misstyped properties)
• Easy debug options with commandline arguments

• [NSPredicate explainWithObject:]

• [NSPredicate explain]

• [NSFetchRequest explainWithResult:]

• [NSFetchRequest explainWithObject:]

• [NSFetchRequest explain]

• [NSManagedObjectContext explainFetchRequest: showIgnored:]

• [NSManagedObjectContext explainFetchRequest:]

• [NSArray explainWithPredicate:]

• [NSSet explainWithPredicate:]

-ExplainFetchRequests YES

This will enable a method swizzling and print a description for every fetchrequest executed.

-ExplainFetchRequestsAggregateOnly YES

Only show aggregation not every element of the fetch result

-ExplainFetchRequestsFetchLimit 100

Only explain the number of objects (default: 100)

Look in NSObject+Explain.h it's very easy and there are some examples on how to use it for other purposes.

I hope you enjoy it

Florian Agsteiner Twitter: @_dvplr