[cycript.git] / website / index.html

<html><head><title>Cycript</title>
</head><body>

<h1>Cycript: Objective-JavaScript</h1>

<h3>What is Cycript?</h3>

<p>A programming language designed to blend the barrier between Objective-C and JavaScript. This project has similar goals to JSCocoa, but a very different set of starting technologies and a different guiding philosophy. In particular, Cycript has started life with a full-blown JavaScript parser/serializer, allowing it to have interesting hybrid syntax without constraints (such as those imposed on JSCocoa by JSLint).</p>

<h3>Is it done?</h3>

<p>Well, it works ;P. It is still "in flux": core language features are changing every few hours. However, it has already changed the workflow of the "elite" iPhone developers that write most of the extensions you see in Cydia: having a language that changes doesn't matter when you are mostly using it at the immediate console. I'm hoping, however, that I manage tolock it into something that feels "correct" in the very near future.</p>

<h3>How do you pronounce "Cycript"?</h3>

<p>I pronounce it "sscript" (with a geminate, aka long, 's'). I doubt anyone else will pronounce it like this, but I have my hopes.</p>

<h3>Where do I get it?</h3>

<p>Right now you can find releases of it at: <a href="http://www.cycript.org/debs/">http://www.cycript.org/debs/</a>. This package depends on MobileSubstrate and libffi (both of which are in Cydia).</p>

<h3>So, how do I use it?!</h3>

<p>Although you can write full applications in Cycript, the fastest way to get playing with it is via the immediate console: just type "cycript".<p>

<xmp>iPhone:~$ cycript
cy# </xmp>

<p>Code typed at this prompt will be executed as it is able to be parsed: the immediate console is trying to eagerly parse lines of code as they come in (and thereby is not subject to automatic-semicolon insertion, for those JavaScript experts). Parse errors will be noted to the output in a hopefully useful fashion.</p>

<xmp>cy# function a() {
cy>    a + q r
  | .........^
  | syntax error, unexpected Identifier, expecting ; or "\n"
cy# </xmp>

<p>It should be noted that it is possible that you will manage to break my JavaScript serializer. In these cases, parse errors may be thrown by the underlying JavaScript engine rather than Cycript. To debug these issues you can use the special console command ?debug.</p>

<xmp>cy# ?debug
debug == true
cy# var a = ((0 + (1)) * (2 * 3)) + m['a']('\'')
var a=(0+1)*(2*3)+m.a("'");
...</xmp>

<p>Because Cycript is implemented as a Cycript->JavaScript compiler, it is able to add functionality that may be lacking in the underlying JavaScript implementation. Right now, Cycript supports array comprehensions and for each loops.</p>

<xmp>cy# function range(b, e) { var q = []; for (var i = b; i != e; ++i) q.push(i); return q; }
cy# ?debug
debug == true
cy# e = []; for each (var i in range(1, 4)) e.push(i); e
e=[];with({$cys:0,$cyt:0}){$cys=range(1,4);for($cyt in $cys){i=$cys[$cyt];e.push(i);}}e;
[1,2,3]
cy# evens = [i for each (i in range(0, 21)) if (i % 2 == 0)]
evens=(function($cyv,i){$cyv=[];(function($cys){$cys=range(0,21);for(i in $cys){i=$cys[i];if(i%2==0)$cyv.push(i);}}());return $cyv;}());
[0,2,4,6,8,10,12,14,16,18,20]</xmp>

<p>In addition to standard JavaScript, you an also access anything in the Objective-C runtime. Attempts have been made, sparingly, to bridge syntax when possible between the two environments. In particular, you may notice interesting properties of arrays, dictonaries, strings, and numbers. Care has been taken to minimize the damage to the object model.</p>

<xmp>cy# var a = [NSMutableArray arrayWithCapacity:4]
cy# a instanceof Array
true
cy# [a class]
"NSCFArray"
cy# [a addObject:"hello"]; a
["hello"]
cy# a[1] = 4; a.push(10); a
["hello",4,10]
cy# a.splice(1, 1, 6, 7); a
["hello",6,7,10]
cy# b = [1, 2]; [b replaceObjectAtIndex:0 withObject:5]; b
[5,2]</xmp>

<p>Memory management is mostly automatic, but instead of using the usual -[alloc] message you will need to use JavaScript's "new" operator, which returns a special "uninitialized" handle that can be used to send a single message (probably a form of init) before it "expires" and reverts to nil.</p>

<xmp>cy# var a = new NSMutableDictionary
cy# a
"*** -[NSCFDictionary count]: method sent to an uninitialized mutable dictionary object"
cy# var b = [a init]; b
{}
cy# a
nil
cy# var q = [new NSString init]; q
""</xmp>

<p>One note in particular is made about selectors. Not only do they act as in Objective-C, including being typed using @selector notation, but they also have Function.prototype in their prototype-chain, allowing you to use them in interesting functional ways ala JavaScript. You can also generate one from a string using new Selector().</p>

<xmp>cy# var sel = @selector(initWithFrame:)
cy# sel
@selector(initWithFrame:)
cy# sel.call(new UIView, [UIHardware fullScreenApplicationContentRect])
"<UIView: 0x22dae0; frame = (0 20; 320 460); layer = <CALayer: 0x209990>>"
cy# new Selector("initWithFrame:")
@selector(initWithFrame:)</xmp>

<p>As one would expect from JavaScript, objects have a property called constructor that references their class. You can also add methods along the prototype chain to instances. Eventually, all objects go through Instance, where you can put functions that should be available for all Objective-C classes.</p>

<xmp>cy# Instance.prototype.getMethod = function (sel) { return class_getInstanceMethod(this, sel); }
{}
cy# NSObject.getMethod(@selector(init))
0x801354
cy# NSObject.prototype.getMethod = function (sel) { return "ark"; }
{}
cy# NSObject.getMethod(@selector(init))
"ark"</xmp>

<p>Given that sending messages is actually a different namespace than function resolution, it is important to separate out the analog of a "prototype" in the world of Objective-C from that in JavaScript. Therefore, a field called "messages" (may change) is also added to Class objects. These messages can even be traded around and reassigned, with the results fully mapping back to the Objective-C runtime.</p>

<xmp>cy# var view = [new UIView init]
cy# view.constructor
"UIView"
cy# view.constructor.messages['description']
0x309d84f5
cy# [view description]
"<UIView: 0x229bc0; frame = (0 0; 0 0); layer = <CALayer: 0x229d60>>"
cy# view.constructor.messages['description'] = function () { return "not!"; }
{}
cy# [view description]
"not!"</xmp>

<p>Structures are also supported (although unions are currently on the todo list and bitfields are still DOA): they are bridged back/forth as much as possible. You can specify them using either array syntax or in the form of dictionaries.</p>

<xmp>cy# var rect = [UIHardware fullScreenApplicationContentRect]
cy# rect
{origin:{x:0,y:20},size:{width:320,height:460}}
cy# rect.origin = [2, 3]
[2,3]
cy# rect.size = {width: 0, height: 1}
{width:0,height:1}
cy# rect
{origin:{x:2,y:3},size:{width:0,height:1}}</xmp>

<p>Access, allocation, and casting of pointers is possible through the usage of the Pointer and Type classes. Pointers can be indirected using the * and -> operators, as in C.</p>

<xmp>cy# var count = new new Type("I")
cy# var methods = class_copyMethodList(UIApplication, count)
cy# *count
305
cy# *new Pointer(count, "d")
7.304555902977629e-304
cy# free(count)
cy# methods
0x843800
cy# methods[304]
0x825248
cy# method_getName(methods[304])
@selector(init)</xmp>

<p>Objective-C @properties (some of which are auto-detected, as Apple doesn't always compile them into the resulting binaries) can be accessed using . notation. Currently, auto-detected @properties are usable, but aren't enumerable. This namespace is strictly separated from that of instance variables, which you can access by indirecting the object using * or ->.</p>

<xmp>cy# var view = [new UIView init]
cy# ps = []; for (var p in view) ps.push(p); ps
["skipsSubviewEnumeration","gestureRecognizers","gesturesEnabled","capturesDescendantTouches","deliversTouchesForGesturesToSuperview","userInteractionEnabled","layer","tag"]
cy# vs = []; for (var v in *view) vs.push(v); vs
["isa","_layer","_tapInfo","_gestureInfo","_gestureRecognizers","_charge","_tag","_viewFlags"]
cy# view.layer
"<CALayer: 0x228f60>"
cy# view->_layer
"<CALayer: 0x228f60>"
cy# (*view)._layer
"<CALayer: 0x228f60>"</xmp>

<p>Fully-fledged Objective-C classes can also be declared using @class, which blurs the line between Objective-C's @interface and @implementation. Right now, declaring instance variables are not supported, but will be in a future version: for now you must provide an empty variable block.</p>

<xmp>cy# @class TestClass : NSObject {
cy> }
cy> - description {
cy>     return "test";
cy> }
cy> @end
cy# [new TestClass init]
"test"</xmp>

<p>The @class syntax can also be used to extend existing classes in a manner similar to categories. Note that type signatures, however, are not yet supported, so you end up heavily restricted in what you can add via this mechanism. In this case, one can also use a parenthesized expression as the class name.</p>

<xmp>cy# @class NSObject
cy> - description { return "replaced"; }
cy> @end
cy# var o = [new NSObject init]
cy# o
"replaced"
cy# @class ([o class]) - description { return "again"; } @end
cy# o
"again"</xmp>

<p>Cycript is also capable of accessing normal C functions and variables. Knowledge of the type signatures of various functions are provided in the bridge definition file, which is currently a plist stored at /usr/lib/libcycript.plist.</p>

<xmp>cy# malloc
0x31d48389
cy# var p = malloc(4)
cy# p
0x22e0a0
cy# free(p)
cy# </xmp>

<p>Cycript attempts to do its best to serialize information to the console about objects. In particular, CoreFoundaton objects bridged to Objective-C are detected and printed using CFCopyDescription.</p>

<xmp>cy# UIGetScreenImage()
"<CGImage 0x22f540>"
cy# ABAddressBookCreate()
"<ABCAddressBook 0x229cf0 [0x38208484]>"</xmp>

<h3>How do I write an application with it?</h3>

<p>This isn't quite "ready for primetime", but you can download the example HelloCycript.app from <a href="http://www.cycript.org/examples/">http://www.cycript.org/examples/</a> and put it in /Applicatons.</p>

<h3>What else can it do?</h3>

<p>Probably the awesomest thing you can do with Cycript is to hook into an existing process using the -p argument to the console interpreter. As an example, let's hook our way into SpringBoard and start spelunking.</p>

<xmp>iPhone:~$ ps ax | grep Spring
18110   ??  Us     0:03.03 /System/Library/CoreServices/SpringBoard.app/SpringBoard
18115 s006  S+     0:00.02 grep --color=auto --exclude=.svn Spring
iPhone:~$ cycript -p 18110
cy# UIApp
"<SpringBoard: 0x266f00>"
cy# UIApp->_uiController.window
"<SBAppWindow: 0x27ac10; baseClass = UIWindow; frame = (0 0; 320 480); layer = <CALayer: 0x27aba0>>"
cy# UIApp->_uiController.window.subviews
["<UIView: 0x4a6efa0; frame = (0 0; 320 480); autoresize = W+H; layer = <CALayer: 0x4a62d70>>","<SBAppContextHostView: 0x49a68f0; frame = (0 0; 320 480); clipsToBounds = YES; hidden = YES; layer = <CALayer: 0x2b4d10>> enabled: yes, context array: (\n)","<SBAppContextHostView: 0x4b5ccf0; frame = (0 0; 320 480); clipsToBounds = YES; hidden = YES; layer = <CALayer: 0x4b7f180>> enabled: yes, context array: (\n)"]
cy# UIApp->_uiController.window.subviews[0].subviews
["<UIImageView: 0x4b3cea0; frame = (0 0; 320 480); opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x4a75550>>","<UIView: 0x4b4ba80; frame = (0 0; 320 480); autoresize = W+H; layer = <CALayer: 0x4b4bbf0>>"]
cy# UIApp->_uiController.window.subviews[0].subviews[0].image.size
{width:320,height:480}
cy# UIApp->_uiController.window.subviews[0].subviews[1].subviews
["<SBIconContentView: 0x4b4bc20; frame = (0 40; 320 349); autoresize = H; layer = <CALayer: 0x4a613c0>>","<UIView: 0x4a25250; frame = (0 389; 320 91); layer = <CALayer: 0x4a38630>>"]
cy# UIApp->_uiController.window.subviews[0].subviews[1].subviews[0].subviews
["<SBIconListPageControl: 0x27aab0; baseClass = UIPageControl; frame = (0 330; 320 19); autoresize = TM; layer = <CALayer: 0x4b3c370>>","<SBIconScrollView: 0x4a62360; baseClass = UIScrollView; frame = (0 0; 320 330); autoresize = H; layer = <CALayer: 0x4a624e0>>"]
cy# var pages = UIApp->_uiController.window.subviews[0].subviews[1].subviews[0].subviews[0]
cy# pages.currentPage
1
cy# pages.numberOfPages
15</xmp>

</body></html>
Commit	Line	Data
2f8f4d8d JF	1	<html><head><title>Cycript</title>
	2	</head><body>
	3
	4	<h1>Cycript: Objective-JavaScript</h1>
	5
	6	<h3>What is Cycript?</h3>
	7
	8	<p>A programming language designed to blend the barrier between Objective-C and JavaScript. This project has similar goals to JSCocoa, but a very different set of starting technologies and a different guiding philosophy. In particular, Cycript has started life with a full-blown JavaScript parser/serializer, allowing it to have interesting hybrid syntax without constraints (such as those imposed on JSCocoa by JSLint).</p>
	9
	10	<h3>Is it done?</h3>
	11
	12	<p>Well, it works ;P. It is still "in flux": core language features are changing every few hours. However, it has already changed the workflow of the "elite" iPhone developers that write most of the extensions you see in Cydia: having a language that changes doesn't matter when you are mostly using it at the immediate console. I'm hoping, however, that I manage tolock it into something that feels "correct" in the very near future.</p>
	13
	14	<h3>How do you pronounce "Cycript"?</h3>
	15
	16	<p>I pronounce it "sscript" (with a geminate, aka long, 's'). I doubt anyone else will pronounce it like this, but I have my hopes.</p>
	17
	18	<h3>Where do I get it?</h3>
	19
	20	<p>Right now you can find releases of it at: <a href="http://www.cycript.org/debs/">http://www.cycript.org/debs/</a>. This package depends on MobileSubstrate and libffi (both of which are in Cydia).</p>
	21
	22	<h3>So, how do I use it?!</h3>
	23
	24	<p>Although you can write full applications in Cycript, the fastest way to get playing with it is via the immediate console: just type "cycript".<p>
	25
	26	<xmp>iPhone:~$ cycript
	27	cy# </xmp>
	28
	29	<p>Code typed at this prompt will be executed as it is able to be parsed: the immediate console is trying to eagerly parse lines of code as they come in (and thereby is not subject to automatic-semicolon insertion, for those JavaScript experts). Parse errors will be noted to the output in a hopefully useful fashion.</p>
	30
	31	<xmp>cy# function a() {
	32	cy> a + q r
	33	\| .........^
	34	\| syntax error, unexpected Identifier, expecting ; or "\n"
	35	cy# </xmp>
	36
	37	<p>It should be noted that it is possible that you will manage to break my JavaScript serializer. In these cases, parse errors may be thrown by the underlying JavaScript engine rather than Cycript. To debug these issues you can use the special console command ?debug.</p>
	38
	39	<xmp>cy# ?debug
	40	debug == true
	41	cy# var a = ((0 + (1)) * (2 * 3)) + m['a']('\'')
	42	var a=(0+1)(23)+m.a("'");
	43	...</xmp>
	44
e40d5faa JF	45	<p>Because Cycript is implemented as a Cycript->JavaScript compiler, it is able to add functionality that may be lacking in the underlying JavaScript implementation. Right now, Cycript supports array comprehensions and for each loops.</p>
	46
	47	<xmp>cy# function range(b, e) { var q = []; for (var i = b; i != e; ++i) q.push(i); return q; }
	48	cy# ?debug
	49	debug == true
	50	cy# e = []; for each (var i in range(1, 4)) e.push(i); e
	51	e=[];with({$cys:0,$cyt:0}){$cys=range(1,4);for($cyt in $cys){i=$cys[$cyt];e.push(i);}}e;
	52	[1,2,3]
	53	cy# evens = [i for each (i in range(0, 21)) if (i % 2 == 0)]
	54	evens=(function($cyv,i){$cyv=[];(function($cys){$cys=range(0,21);for(i in $cys){i=$cys[i];if(i%2==0)$cyv.push(i);}}());return $cyv;}());
	55	[0,2,4,6,8,10,12,14,16,18,20]</xmp>
	56
2f8f4d8d JF	57	<p>In addition to standard JavaScript, you an also access anything in the Objective-C runtime. Attempts have been made, sparingly, to bridge syntax when possible between the two environments. In particular, you may notice interesting properties of arrays, dictonaries, strings, and numbers. Care has been taken to minimize the damage to the object model.</p>
	58
	59	<xmp>cy# var a = [NSMutableArray arrayWithCapacity:4]
	60	cy# a instanceof Array
	61	true
	62	cy# [a class]
	63	"NSCFArray"
	64	cy# [a addObject:"hello"]; a
	65	["hello"]
	66	cy# a[1] = 4; a.push(10); a
	67	["hello",4,10]
	68	cy# a.splice(1, 1, 6, 7); a
	69	["hello",6,7,10]
	70	cy# b = [1, 2]; [b replaceObjectAtIndex:0 withObject:5]; b
	71	[5,2]</xmp>
	72
	73	<p>Memory management is mostly automatic, but instead of using the usual -[alloc] message you will need to use JavaScript's "new" operator, which returns a special "uninitialized" handle that can be used to send a single message (probably a form of init) before it "expires" and reverts to nil.</p>
	74
	75	<xmp>cy# var a = new NSMutableDictionary
	76	cy# a
	77	"*** -[NSCFDictionary count]: method sent to an uninitialized mutable dictionary object"
	78	cy# var b = [a init]; b
	79	{}
	80	cy# a
	81	nil
	82	cy# var q = [new NSString init]; q
	83	""</xmp>
	84
	85	<p>One note in particular is made about selectors. Not only do they act as in Objective-C, including being typed using @selector notation, but they also have Function.prototype in their prototype-chain, allowing you to use them in interesting functional ways ala JavaScript. You can also generate one from a string using new Selector().</p>
	86
	87	<xmp>cy# var sel = @selector(initWithFrame:)
	88	cy# sel
	89	@selector(initWithFrame:)
	90	cy# sel.call(new UIView, [UIHardware fullScreenApplicationContentRect])
	91	"<UIView: 0x22dae0; frame = (0 20; 320 460); layer = <CALayer: 0x209990>>"
	92	cy# new Selector("initWithFrame:")
	93	@selector(initWithFrame:)</xmp>
	94
7ac075c2 JF	95	<p>As one would expect from JavaScript, objects have a property called constructor that references their class. You can also add methods along the prototype chain to instances. Eventually, all objects go through Instance, where you can put functions that should be available for all Objective-C classes.</p>
	96
	97	<xmp>cy# Instance.prototype.getMethod = function (sel) { return class_getInstanceMethod(this, sel); }
	98	{}
	99	cy# NSObject.getMethod(@selector(init))
	100	0x801354
	101	cy# NSObject.prototype.getMethod = function (sel) { return "ark"; }
	102	{}
	103	cy# NSObject.getMethod(@selector(init))
	104	"ark"</xmp>
	105
	106	<p>Given that sending messages is actually a different namespace than function resolution, it is important to separate out the analog of a "prototype" in the world of Objective-C from that in JavaScript. Therefore, a field called "messages" (may change) is also added to Class objects. These messages can even be traded around and reassigned, with the results fully mapping back to the Objective-C runtime.</p>
2f8f4d8d JF	107
	108	<xmp>cy# var view = [new UIView init]
	109	cy# view.constructor
	110	"UIView"
7ac075c2	111	cy# view.constructor.messages['description']
2f8f4d8d JF	112	0x309d84f5
	113	cy# [view description]
	114	"<UIView: 0x229bc0; frame = (0 0; 0 0); layer = <CALayer: 0x229d60>>"
7ac075c2	115	cy# view.constructor.messages['description'] = function () { return "not!"; }
2f8f4d8d JF	116	{}
	117	cy# [view description]
	118	"not!"</xmp>
	119
	120	<p>Structures are also supported (although unions are currently on the todo list and bitfields are still DOA): they are bridged back/forth as much as possible. You can specify them using either array syntax or in the form of dictionaries.</p>
	121
	122	<xmp>cy# var rect = [UIHardware fullScreenApplicationContentRect]
	123	cy# rect
	124	{origin:{x:0,y:20},size:{width:320,height:460}}
	125	cy# rect.origin = [2, 3]
	126	[2,3]
	127	cy# rect.size = {width: 0, height: 1}
	128	{width:0,height:1}
	129	cy# rect
	130	{origin:{x:2,y:3},size:{width:0,height:1}}</xmp>
	131
	132	<p>Access, allocation, and casting of pointers is possible through the usage of the Pointer and Type classes. Pointers can be indirected using the * and -> operators, as in C.</p>
	133
	134	<xmp>cy# var count = new new Type("I")
	135	cy# var methods = class_copyMethodList(UIApplication, count)
	136	cy# *count
	137	305
	138	cy# *new Pointer(count, "d")
	139	7.304555902977629e-304
	140	cy# free(count)
	141	cy# methods
	142	0x843800
	143	cy# methods[304]
	144	0x825248
	145	cy# method_getName(methods[304])
	146	@selector(init)</xmp>
	147
	148	<p>Objective-C @properties (some of which are auto-detected, as Apple doesn't always compile them into the resulting binaries) can be accessed using . notation. Currently, auto-detected @properties are usable, but aren't enumerable. This namespace is strictly separated from that of instance variables, which you can access by indirecting the object using * or ->.</p>
	149
	150	<xmp>cy# var view = [new UIView init]
	151	cy# ps = []; for (var p in view) ps.push(p); ps
	152	["skipsSubviewEnumeration","gestureRecognizers","gesturesEnabled","capturesDescendantTouches","deliversTouchesForGesturesToSuperview","userInteractionEnabled","layer","tag"]
	153	cy# vs = []; for (var v in *view) vs.push(v); vs
	154	["isa","_layer","_tapInfo","_gestureInfo","_gestureRecognizers","_charge","_tag","_viewFlags"]
	155	cy# view.layer
	156	"<CALayer: 0x228f60>"
	157	cy# view->_layer
	158	"<CALayer: 0x228f60>"
	159	cy# (*view)._layer
	160	"<CALayer: 0x228f60>"</xmp>
	161
	162	<p>Fully-fledged Objective-C classes can also be declared using @class, which blurs the line between Objective-C's @interface and @implementation. Right now, declaring instance variables are not supported, but will be in a future version: for now you must provide an empty variable block.</p>
	163
	164	<xmp>cy# @class TestClass : NSObject {
	165	cy> }
	166	cy> - description {
	167	cy> return "test";
	168	cy> }
	169	cy> @end
	170	cy# [new TestClass init]
	171	"test"</xmp>
	172
	173	<p>The @class syntax can also be used to extend existing classes in a manner similar to categories. Note that type signatures, however, are not yet supported, so you end up heavily restricted in what you can add via this mechanism. In this case, one can also use a parenthesized expression as the class name.</p>
	174
	175	<xmp>cy# @class NSObject
	176	cy> - description { return "replaced"; }
	177	cy> @end
	178	cy# var o = [new NSObject init]
	179	cy# o
180	"replaced"
181	cy# @class ([o class]) - description { return "again"; } @end
182	cy# o
183	"again"</xmp>
184
185	<p>Cycript is also capable of accessing normal C functions and variables. Knowledge of the type signatures of various functions are provided in the bridge definition file, which is currently a plist stored at /usr/lib/libcycript.plist.</p>
186
187	<xmp>cy# malloc
188	0x31d48389
189	cy# var p = malloc(4)
190	cy# p
191	0x22e0a0
192	cy# free(p)
193	cy# </xmp>
194
195	<p>Cycript attempts to do its best to serialize information to the console about objects. In particular, CoreFoundaton objects bridged to Objective-C are detected and printed using CFCopyDescription.</p>
196
197	<xmp>cy# UIGetScreenImage()
198	"<CGImage 0x22f540>"
199	cy# ABAddressBookCreate()
200	"<ABCAddressBook 0x229cf0 [0x38208484]>"</xmp>
201
202	<h3>How do I write an application with it?</h3>
203
204	<p>This isn't quite "ready for primetime", but you can download the example HelloCycript.app from <a href="http://www.cycript.org/examples/">http://www.cycript.org/examples/</a> and put it in /Applicatons.</p>
205
206	<h3>What else can it do?</h3>
207
208	<p>Probably the awesomest thing you can do with Cycript is to hook into an existing process using the -p argument to the console interpreter. As an example, let's hook our way into SpringBoard and start spelunking.</p>
209
210	<xmp>iPhone:~$ ps ax \| grep Spring
211	18110 ?? Us 0:03.03 /System/Library/CoreServices/SpringBoard.app/SpringBoard
212	18115 s006 S+ 0:00.02 grep --color=auto --exclude=.svn Spring
213	iPhone:~$ cycript -p 18110
214	cy# UIApp
215	"<SpringBoard: 0x266f00>"
216	cy# UIApp->_uiController.window
217	"<SBAppWindow: 0x27ac10; baseClass = UIWindow; frame = (0 0; 320 480); layer = <CALayer: 0x27aba0>>"
218	cy# UIApp->_uiController.window.subviews
219	["<UIView: 0x4a6efa0; frame = (0 0; 320 480); autoresize = W+H; layer = <CALayer: 0x4a62d70>>","<SBAppContextHostView: 0x49a68f0; frame = (0 0; 320 480); clipsToBounds = YES; hidden = YES; layer = <CALayer: 0x2b4d10>> enabled: yes, context array: (\n)","<SBAppContextHostView: 0x4b5ccf0; frame = (0 0; 320 480); clipsToBounds = YES; hidden = YES; layer = <CALayer: 0x4b7f180>> enabled: yes, context array: (\n)"]
220	cy# UIApp->_uiController.window.subviews[0].subviews
221	["<UIImageView: 0x4b3cea0; frame = (0 0; 320 480); opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x4a75550>>","<UIView: 0x4b4ba80; frame = (0 0; 320 480); autoresize = W+H; layer = <CALayer: 0x4b4bbf0>>"]
222	cy# UIApp->_uiController.window.subviews[0].subviews[0].image.size
223	{width:320,height:480}
224	cy# UIApp->_uiController.window.subviews[0].subviews[1].subviews
225	["<SBIconContentView: 0x4b4bc20; frame = (0 40; 320 349); autoresize = H; layer = <CALayer: 0x4a613c0>>","<UIView: 0x4a25250; frame = (0 389; 320 91); layer = <CALayer: 0x4a38630>>"]
226	cy# UIApp->_uiController.window.subviews[0].subviews[1].subviews[0].subviews
227	["<SBIconListPageControl: 0x27aab0; baseClass = UIPageControl; frame = (0 330; 320 19); autoresize = TM; layer = <CALayer: 0x4b3c370>>","<SBIconScrollView: 0x4a62360; baseClass = UIScrollView; frame = (0 0; 320 330); autoresize = H; layer = <CALayer: 0x4a624e0>>"]
228	cy# var pages = UIApp->_uiController.window.subviews[0].subviews[1].subviews[0].subviews[0]
229	cy# pages.currentPage
230	1
231	cy# pages.numberOfPages
232	15</xmp>
233
234	</body></html>