objc-class-tree can print a nice tree of Objective-C classes.
By default, it will print a huge tree of all the classes loaded in its own binary:
$ objc-class-tree | head -30
NSProxy
_NSZombie_
__NSMessageBuilder
__NSGenericDeallocHandler
Object
NSObject
├── OCTMethod
├── OCTTreeFormatter
├── NSURLDownload
├── NSXPCInterface
├── NSAppleEventDescriptor
├── NSFileWrapper
│ ├── NSFileWrapperLink
│ ├── NSFileWrapperDirectory
│ └── NSFileWrapperFile
├── NSURLSessionConfiguration
├── NSSpellEngine
├── NSXMLParser
├── NSXMLNode
│ ├── NSXMLElement
│ ├── NSXMLDTDNode
│ ├── NSXMLDTD
│ └── NSXMLDocument
├── NSValueTransformer
│ └── _NSSharedValueTransformer
│ ├── _NSUnarchiveFromDataTransformer
│ ├── _NSKeyedUnarchiveFromDataTransformer
│ └── _NSNegateBooleanTransformer
│ ├── _NSIsNotNilTransformer
│ └── _NSIsNilTransformer
$ objc-class-tree | wc -l
401
You can limit its output to a handful of class trees by using the --root-class option:
$ objc-class-tree --root-class NSArray --root-class NSXMLNode
NSArray
├── NSKeyValueArray
├── __NSOrderedSetArrayProxy
├── __NSArrayI
└── NSMutableArray
├── NSKeyValueMutableArray
│ ├── NSKeyValueNotifyingMutableArray
│ ├── NSKeyValueIvarMutableArray
│ ├── NSKeyValueFastMutableArray
│ │ ├── NSKeyValueFastMutableArray2
│ │ └── NSKeyValueFastMutableArray1
│ └── NSKeyValueSlowMutableArray
├── __NSPlaceholderArray
└── __NSCFArray
NSXMLNode
├── NSXMLElement
├── NSXMLDTDNode
├── NSXMLDTD
└── NSXMLDocument
You can ask it to output implemented methods:
$ objc-class-tree --root-class NSURLResponse --methods
NSURLResponse
├── - init
├── - dealloc
├── - copyWithZone:
├── - initWithCoder:
├── - encodeWithCoder:
├── - URL
├── - _CFURLResponse
├── - _initWithCFURLResponse:
├── - initWithURL:MIMEType:expectedContentLength:textEncodingName:
├── - suggestedFilename
├── - expectedContentLength
├── - textEncodingName
├── - MIMEType
├── + _responseWithCFURLResponse:
└── NSHTTPURLResponse
├── - initWithCoder:
├── - statusCode
├── - _initWithCFURLResponse:
├── - initWithURL:statusCode:HTTPVersion:headerFields:
├── - initWithURL:statusCode:headerFields:requestTime:
├── - _peerTrust
├── - _setPeerTrust:
├── - _clientCertificateState
├── - _clientCertificateChain
├── - _peerCertificateChain
├── - allHeaderFields
├── + supportsSecureCoding
├── + isErrorStatusCode:
└── + localizedStringForStatusCode:
It can also display protocols and which libraries the classes come from:
$ objc-class-tree --root-class NSString --protocols --library-names
NSString <NSCopying, NSMutableCopying, NSSecureCoding> (Foundation)
├── NSSimpleCString (Foundation)
│ └── NSConstantString (Foundation)
├── NSPathStore2 (Foundation)
├── NSLocalizableString <NSCoding, NSCopying> (Foundation)
├── NSPlaceholderString (Foundation)
└── NSMutableString (Foundation)
├── NSPlaceholderMutableString (Foundation)
├── NSMutableStringProxyForMutableAttributedString (Foundation)
└── __NSCFString (CoreFoundation)
└── __NSCFConstantString (CoreFoundation)
See main.m for more supported options.
Build using Meson as usual:
$ meson build $ cd build $ ninja build # optionally $ sudo ninja install
objc-class-tree is free software, available under the GNU General Public License version 3 or later.