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'''Cycript''' is a | '''Cycript''' is a JavaScript interpreter which also understands Objective-C syntax. The <tt>cycript</tt> binary is also a [http://en.wikipedia.org/wiki/Read-eval-print_loop REPL] for this language. | ||
Besides evaluating scripts, Cycript can also hook into a running process (using <tt>cycript -p </tt>''process'') and modify its property. | Besides evaluating scripts, Cycript can also hook into a running process (using <tt>cycript -p </tt>''process'') and modify its property. | ||
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== JS/ObjC Object Bridging == | == JS/ObjC Object Bridging == | ||
Some native | Some native JavaScript types are bridged to the corresponding Objective-C types for convenient, so you can use | ||
<source lang="javascript">[[41,"foo",true,[8,6],{a:12,b:46},36] indexOfObject:"foo"]</source> | <source lang="javascript">[[41,"foo",true,[8,6],{a:12,b:46},36] indexOfObject:"foo"]</source> | ||
instead of | instead of | ||
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<tt>null</tt> in Cycript is equivalent to <tt>nil</tt> in Objective-C. Additionally, <tt>nil</tt>, <tt>YES</tt> and <tt>NO</tt> are also defined in Cycript. | <tt>null</tt> in Cycript is equivalent to <tt>nil</tt> in Objective-C. Additionally, <tt>nil</tt>, <tt>YES</tt> and <tt>NO</tt> are also defined in Cycript. | ||
== | == JavaScript 1.6+ Features == | ||
Cycript supports the following | Cycript supports the following JavaScript 1.6+ features extended by Mozilla: | ||
* [https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Statements/for_each...in <tt>for each/in</tt>] (JS1.6) | * [https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Statements/for_each...in <tt>for each/in</tt>] (JS1.6) | ||
* [https://developer.mozilla.org/en/New_in_JavaScript_1.7#Array_comprehensions Array comprehensions] (JS1.7) | * [https://developer.mozilla.org/en/New_in_JavaScript_1.7#Array_comprehensions Array comprehensions] (JS1.7) |
Revision as of 20:28, 22 September 2014
Cycript | |
Cydia Package | |
---|---|
Developer | saurik |
Package ID | cycript |
Latest Version | 0.9.502 |
Cycript is a JavaScript interpreter which also understands Objective-C syntax. The cycript binary is also a REPL for this language.
Besides evaluating scripts, Cycript can also hook into a running process (using cycript -p process) and modify its property.
Official documentation can be found on cycript.org.
Presentations about Cycript: saurik explaining how to use Cycript on OS X, targeting the iOS simulator; Adam Bell explaining how to use Cycript to prototype a tweak (example code).
JS/ObjC Object Bridging
Some native JavaScript types are bridged to the corresponding Objective-C types for convenient, so you can use
[[41,"foo",true,[8,6],{a:12,b:46},36] indexOfObject:"foo"]
instead of
[[NSArray arrayWithObjects:
[NSNumber numberWithInt:41],
"foo",
[NSNumber numberWithBool:YES],
[NSArray arrayWithObjects:[NSNumber numberWithInt:8], [NSNumber numberWithInt:6], nil],
[NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:12], "a",
[NSNumber numberWithInt:46], "b",
nil],
[NSNumber numberWithInt:36],
nil] indexOfObject:"foo"]
JS type | ObjC type |
---|---|
number | NSNumber (CFNumber) |
boolean | NSNumber (CFBoolean) |
string | NSString |
Array | NSArray |
object (Associative array) | NSDictionary |
null in Cycript is equivalent to nil in Objective-C. Additionally, nil, YES and NO are also defined in Cycript.
JavaScript 1.6+ Features
Cycript supports the following JavaScript 1.6+ features extended by Mozilla:
- for each/in (JS1.6)
- Array comprehensions (JS1.7)
- E4X (not available on iPhoneOS).
Additional syntax
New Syntax | Meaning | "Desugared" representation |
---|---|---|
[obj msg:var] | Sends msg to obj with parameters var. This is the Objective-C's message sending syntax. | objc_msgSend(obj, @selector(msg).value, var ...) |
@import(module) | Import a .cy file. Similar to JavaScript's require() function. | |
@selector(selname) | Returns the selector named selname with Objective-C syntax. | new Selector("selname"); |
obj->ivar | Obtain the instant variable ivar of an Objective-C object obj. | obj.$cyi.ivar |
*ptr | Dereference the pointer, or list all ivars of an object (so that you can access them using (*obj).ivar). | ptr.$cyi |
obj->[key] | Equivalent to (*obj)[key]. | |
&var | Takes the address of a variable. Only instances of ObjC class can have addresses. | var.$cya() |
@class classname : superclass {} + methodname { function body } - methodname { function body } ... @end |
Declare an Objective-C class. The classname can be omitted, where an anonymous class will be declared. | |
@class existingclass + methodname { function body } - methodname { function body } ... @end |
Insert extra methods to an existing class. The existingclass itself can be an expression e.g. @class ([obj class]) .... | |
new classname | Although not exactly a new syntax, this construction has a new meaning for Objective-C classes. This is similar to [classname alloc], but the resource will be managed by JavaScriptCore's garbage collector. To fully initialize the class, you need to call [new classname initWithFoo:...]. | |
@"str" | Equivalent to "str". | |
[super ...] | A local variable representing the superclass. | objc_msgSend(???, ... ) |
0bxxxxxx | Binary literal. |
REPL-only additions
These are used for debugging.
Line | Usage |
---|---|
?debug | Toggles debug output. |
?bypass | Bypass syntax error pretty-printing. |
?expand | Toggles whether to display the line break characters, etc. as really a line break or just \n. |
?gc | Force a JavaScript garbage collection. |
?syntax | Toggle syntax highlighting. |
Additional types
Type/Constructor | Usage |
---|---|
Selector(selname) | Declare a selector. |
Functor(function body, type encoding) | Associate an Objective-C type encoding to a function, e.g. new Functor(function(x,y){return (x+y).toString(16);}, "*dd"); to declare a (double, double) → char* function. |
Pointer(address, type encoding) | Treat the input number as a pointer. Like C pointers, the result can be dereferenced using * and subscripted using [i], but pointer arithmetic is not directly supported. |
Type(type encoding) | Create a type. The resulting value can be new-ed to get a Pointer, e.g. var p = new new Type("d");. To deallocate the pointer, use the free() function. |
Instance(address) | Treat the address as an instance of Objective-C object. |
Super(self, selector) | Returns an object which, when being sent a message, will be forwarded to self's superclass. |
Additionally, the identifiers like int, id, char, double, etc. are predefined to the corresponding types (new Type("i"), etc). Therefore, to allocator a pointer you may simply use new int or even new int[42].
Additional variables and methods
Variable | Meaning |
---|---|
_ | Last evaluated value (REPL only). |
ObjectiveC.images | An associative array, with keys beings the path of loaded libraries, and value is the classes of this library. |
ObjectiveC.classes | An associative array of classes. The keys are class names and the values are the classes themselves. |
ObjectiveC.protocols | An associative array of protocols. The keys are protocol names and the values are the protocols themselves. |
obj.toJSON() | Convert the object to JSON. |
obj.toCYON() | Convert the object to CYON (Cycript object notation). |
obj.value | For some objects, returns the address. |
class.messages | Contains an associative array of messages in the class. The keys are the selector names and the values are implementations (functions). |
system.print(string) | Print the string to syslog. |
system.args | Parameters of the executable |
selector.type(class) | Returns the type encoding for the selector in class. For example, @selector(copyWithZone:).type(NSString) returns @12@0:4^{_NSZone=}8. |
Other uses
The cycript binary can be used to "compile" Cycript into standard JavaScript 1.5 with the -c flag, e.g.
Your-iPhone:~ mobile$ echo "[x*x for each(x in [1,2,3])]" | cycript -c > x.js
Your-iPhone:~ mobile$ cat x.js
(function($cyv,x){$cyv=[];(function($cys){$cys=[1,2,3];for(x in $cys){x=$cys[x];$cyv.push(x*x)}})();return $cyv})()
See also
References
- Official website: http://www.cycript.org/
- Git tree http://gitweb.saurik.com/cycript.git/tree
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