What's the “cdl” do in TOKENMATCHES[cdl]?

Question

I came across TOKENMATCHES in minute 31 of Introducing CloudKit and was curious, so I did a google search and found very little about it outside of another StackOverflow post.

NSPredicate(format: "ALL tokenize(%@, 'Cdl') IN allTokens", "after session")

Actually, confusing things further, that post uses different syntax than the WWDC video:

NSPredicate(format: "allTokens TOKENMATCHES[cdl] %@", "bob smith")

As I understand it, these queries return any records that have all of the tokenized string arguments within one or more text fields. The latter case would fetch a record with, say, person.name = "bob" and person.last = "smith", as well as, say, a record where person.note = "Bob likes Joseph Smith.". (Corrections welcome.)

All that said, this question isn't about the full predicate, but just that cdl (or Cdl?) parameter/modifier/whateverthehellitis.

TL;DR—What's cdl mean, and are there other values that can go in that "slot" of the format string?

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<rant> Why isn't the predicate syntax documentation comprehensive? It's as if Apple's managers are scared of the mysterious, ancient power that is NSPredicate; none dare assign the technical writer and engineer needed to make this otherwise simple class accessible to the Rest of Us™. A Google search for "nspredicate TOKENMATCHES" gives only 8 results, none of which are at apple.com. 😠 </rant>

Answer 1

Found it, at least!

The doc: NSComparisonPredicateOptions

typedef enum NSComparisonPredicateOptions : NSUInteger {
    NSCaseInsensitivePredicateOption = 0x01,      //==> [c]
    NSDiacriticInsensitivePredicateOption = 0x02, //==> [d]
    NSNormalizedPredicateOption = 0x04            //==> [n]
} NSComparisonPredicateOptions;

+ NSLocaleSensitivePredicateOption                //==> [l]

So basically :
[c]: uppercase is the same as lowercase (ie: A == a)
[d]: char with diacritics (acute accent, cedilla, etc.) is the same as char without it (ie à == a (accent)
[l]: it's for localized specificities. The Apple sample is with "straße" and "strasse" using the German "double s" (Eszett) as an example.