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  "title" : "NSScriptObjectSpecifier—Specifier Evaluation Errors"
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# NSScriptObjectSpecifier—Specifier Evaluation Errors

`NSScriptObjectSpecifier` provides the following constants for error codes for specific problems evaluating specifiers:

## Topics

### Constants

[`var NSNoSpecifierError: Int`](/documentation/Foundation/NSNoSpecifierError)

No error encountered.

[`var NSNoTopLevelContainersSpecifierError: Int`](/documentation/Foundation/NSNoTopLevelContainersSpecifierError)

Someone called `evaluate` with `nil`.

[`var NSContainerSpecifierError: Int`](/documentation/Foundation/NSContainerSpecifierError)

Error evaluating container specifier.

[`var NSUnknownKeySpecifierError: Int`](/documentation/Foundation/NSUnknownKeySpecifierError)

Receivers do not understand the key.

[`var NSInvalidIndexSpecifierError: Int`](/documentation/Foundation/NSInvalidIndexSpecifierError)

Index out of bounds.

[`var NSInternalSpecifierError: Int`](/documentation/Foundation/NSInternalSpecifierError)

Other internal error.

[`var NSOperationNotSupportedForKeySpecifierError: Int`](/documentation/Foundation/NSOperationNotSupportedForKeySpecifierError)

Attempt made to perform an unsupported operation on some key.


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