[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>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, and classes have a property called prototype that gives you access to their messages. These 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.prototype.description
0x309d84f5
cy# [view description]
"<UIView: 0x229bc0; frame = (0 0; 0 0); layer = <CALayer: 0x229d60>>"
cy# view.constructor.prototype.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
	45	<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>
	46
	47	<xmp>cy# var a = [NSMutableArray arrayWithCapacity:4]
	48	cy# a instanceof Array
	49	true
	50	cy# [a class]
	51	"NSCFArray"
	52	cy# [a addObject:"hello"]; a
	53	["hello"]
	54	cy# a[1] = 4; a.push(10); a
	55	["hello",4,10]
	56	cy# a.splice(1, 1, 6, 7); a
	57	["hello",6,7,10]
	58	cy# b = [1, 2]; [b replaceObjectAtIndex:0 withObject:5]; b
	59	[5,2]</xmp>
	60
	61	<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>
	62
	63	<xmp>cy# var a = new NSMutableDictionary
	64	cy# a
65	"*** -[NSCFDictionary count]: method sent to an uninitialized mutable dictionary object"
66	cy# var b = [a init]; b
67	{}
68	cy# a
69	nil
70	cy# var q = [new NSString init]; q
71	""</xmp>
72
73	<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>
74
75	<xmp>cy# var sel = @selector(initWithFrame:)
76	cy# sel
77	@selector(initWithFrame:)
78	cy# sel.call(new UIView, [UIHardware fullScreenApplicationContentRect])
79	"<UIView: 0x22dae0; frame = (0 20; 320 460); layer = <CALayer: 0x209990>>"
80	cy# new Selector("initWithFrame:")
81	@selector(initWithFrame:)</xmp>
82
83	<p>As one would expect from JavaScript, objects have a property called constructor that references their class, and classes have a property called prototype that gives you access to their messages. These can even be traded around and reassigned, with the results fully mapping back to the Objective-C runtime.</p>
84
85	<xmp>cy# var view = [new UIView init]
86	cy# view.constructor
87	"UIView"
88	cy# view.constructor.prototype.description
89	0x309d84f5
90	cy# [view description]
91	"<UIView: 0x229bc0; frame = (0 0; 0 0); layer = <CALayer: 0x229d60>>"
92	cy# view.constructor.prototype.description = function () { return "not!"; }
93	{}
94	cy# [view description]
95	"not!"</xmp>
96
97	<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>
98
99	<xmp>cy# var rect = [UIHardware fullScreenApplicationContentRect]
100	cy# rect
101	{origin:{x:0,y:20},size:{width:320,height:460}}
102	cy# rect.origin = [2, 3]
103	[2,3]
104	cy# rect.size = {width: 0, height: 1}
105	{width:0,height:1}
106	cy# rect
107	{origin:{x:2,y:3},size:{width:0,height:1}}</xmp>
108
109	<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>
110
111	<xmp>cy# var count = new new Type("I")
112	cy# var methods = class_copyMethodList(UIApplication, count)
113	cy# *count
114	305
115	cy# *new Pointer(count, "d")
116	7.304555902977629e-304
117	cy# free(count)
118	cy# methods
119	0x843800
120	cy# methods[304]
121	0x825248
122	cy# method_getName(methods[304])
123	@selector(init)</xmp>
124
125	<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>
126
127	<xmp>cy# var view = [new UIView init]
128	cy# ps = []; for (var p in view) ps.push(p); ps
129	["skipsSubviewEnumeration","gestureRecognizers","gesturesEnabled","capturesDescendantTouches","deliversTouchesForGesturesToSuperview","userInteractionEnabled","layer","tag"]
130	cy# vs = []; for (var v in *view) vs.push(v); vs
131	["isa","_layer","_tapInfo","_gestureInfo","_gestureRecognizers","_charge","_tag","_viewFlags"]
132	cy# view.layer
133	"<CALayer: 0x228f60>"
134	cy# view->_layer
135	"<CALayer: 0x228f60>"
136	cy# (*view)._layer
137	"<CALayer: 0x228f60>"</xmp>
138
139	<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>
140
141	<xmp>cy# @class TestClass : NSObject {
142	cy> }
143	cy> - description {
144	cy> return "test";
145	cy> }
146	cy> @end
147	cy# [new TestClass init]
148	"test"</xmp>
149
150	<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>
151
152	<xmp>cy# @class NSObject
153	cy> - description { return "replaced"; }
154	cy> @end
155	cy# var o = [new NSObject init]
156	cy# o
157	"replaced"
158	cy# @class ([o class]) - description { return "again"; } @end
159	cy# o
160	"again"</xmp>
161
162	<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>
163
164	<xmp>cy# malloc
165	0x31d48389
166	cy# var p = malloc(4)
167	cy# p
168	0x22e0a0
169	cy# free(p)
170	cy# </xmp>
171
172	<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>
173
174	<xmp>cy# UIGetScreenImage()
175	"<CGImage 0x22f540>"
176	cy# ABAddressBookCreate()
177	"<ABCAddressBook 0x229cf0 [0x38208484]>"</xmp>
178
179	<h3>How do I write an application with it?</h3>
180
181	<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>
182
183	<h3>What else can it do?</h3>
184
185	<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>
186
187	<xmp>iPhone:~$ ps ax \| grep Spring
188	18110 ?? Us 0:03.03 /System/Library/CoreServices/SpringBoard.app/SpringBoard
189	18115 s006 S+ 0:00.02 grep --color=auto --exclude=.svn Spring
190	iPhone:~$ cycript -p 18110
191	cy# UIApp
192	"<SpringBoard: 0x266f00>"
193	cy# UIApp->_uiController.window
194	"<SBAppWindow: 0x27ac10; baseClass = UIWindow; frame = (0 0; 320 480); layer = <CALayer: 0x27aba0>>"
195	cy# UIApp->_uiController.window.subviews
196	["<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)"]
197	cy# UIApp->_uiController.window.subviews[0].subviews
198	["<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>>"]
199	cy# UIApp->_uiController.window.subviews[0].subviews[0].image.size
200	{width:320,height:480}
201	cy# UIApp->_uiController.window.subviews[0].subviews[1].subviews
202	["<SBIconContentView: 0x4b4bc20; frame = (0 40; 320 349); autoresize = H; layer = <CALayer: 0x4a613c0>>","<UIView: 0x4a25250; frame = (0 389; 320 91); layer = <CALayer: 0x4a38630>>"]
203	cy# UIApp->_uiController.window.subviews[0].subviews[1].subviews[0].subviews
204	["<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>>"]
205	cy# var pages = UIApp->_uiController.window.subviews[0].subviews[1].subviews[0].subviews[0]
206	cy# pages.currentPage
207	1
208	cy# pages.numberOfPages
209	15</xmp>
210
211	</body></html>