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Diffstat (limited to 'platform/darwin/docs/guides/Predicates and Expressions.md')
| -rw-r--r-- | platform/darwin/docs/guides/Predicates and Expressions.md | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/platform/darwin/docs/guides/Predicates and Expressions.md b/platform/darwin/docs/guides/Predicates and Expressions.md index ee8f831fbd..6b191720b7 100644 --- a/platform/darwin/docs/guides/Predicates and Expressions.md +++ b/platform/darwin/docs/guides/Predicates and Expressions.md @@ -31,6 +31,9 @@ The following comparison operators are supported: `NSNotEqualToPredicateOperatorType` | `key != value`<br />`key <> value` `NSBetweenPredicateOperatorType` | `key BETWEEN { 32, 212 }` +The `key` may be cast explicitly into the key's type. Example: `CAST(key, 'NSNumber')` or +`CAST(key, 'NSString')` + The following compound operators are supported: `NSCompoundPredicateType` | Format string syntax @@ -56,8 +59,11 @@ Format String Syntax” chapter of the _[Predicate Programming Guide](https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/Predicates/AdditionalChapters/Introduction.html)_ in Apple developer documentation. -The predicate's left-hand expression must be a string that identifies a feature -attribute or, alternatively, one of the following special attributes: +Either the predicate’s left-hand or right-hand expression can be an `NSString` +(to match strings) or `NSNumber` (to match numbers, including Boolean values) +or an array of `NSString`s or `NSNumber`s, depending on the operator and the +type of values expected for the attribute being tested or, alternatively, +one of the following special attributes: <table> <thead> @@ -101,12 +107,8 @@ attribute or, alternatively, one of the following special attributes: </tbody> </table> -The predicate’s right-hand expression must be an `NSString` (to match strings) -or `NSNumber` (to match numbers, including Boolean values) or an array of -`NSString`s or `NSNumber`s, depending on the operator and the type of values -expected for the attribute being tested. For floating-point values, use -`-[NSNumber numberWithDouble:]` instead of `-[NSNumber numberWithFloat:]` -to avoid precision issues. +For floating-point values, use `-[NSNumber numberWithDouble:]` instead of +`-[NSNumber numberWithFloat:]` to avoid precision issues. Automatic type casting is not performed. Therefore, a feature only matches this predicate if its value for the attribute in question is of the same type as the @@ -116,10 +118,10 @@ sensitivity) are unsupported for comparison and aggregate operators that are used in the predicate. It is possible to create expressions that contain special characters in the -predicate format syntax. This includes the `$` in the `$id` and `$type` special -style attributes and also `hyphen-minus` and `tag:subtag`. However, you must use -`%K` in the format string to represent these variables: -`@"%K == 'LineString'", @"$type"`. +predicate format syntax. This includes the `$` in the `$featureIdentifier` and +`$geometryType` special style attributes and also `hyphen-minus` and `tag:subtag`. +However, you must use `%@` in the format string to represent these variables: +`@"$geometryType == 'LineString'"`. ## Using expressions to configure layout and paint attributes |