Re: [webkit-dev] A question regarding to JavaScriptCore's C/C++ API.
ping. On Thu, Mar 5, 2009 at 2:44 PM, Zhe Su james...@gmail.com wrote: Hi, I'm developing an application which uses webkit's JavaScriptCore and a customized global object (by providing a special class when creating the context). My customized global object provides some built-in properties that can be accessed by javascript code. Now, I want to support a special behavior: allows javascript code to override a built-in property of global object by using variable declaraction statement. For example, assuming the global object has a built-in property, named foo, a var foo; statement shall create a javascript variable, named foo and the original built-in foo shall be overrid by this new javascript variable. But if there is no var foo; statement, the built-in foo shall be able to get and set from javascript code. Now the problem is, current JavaScriptCore's C API (especially those HasProperty, GetProperty, SetProperty callbacks of a class definition) can't distinguish variable delcaration statement and variable assigment statement. I checked SpiderMonkey's API and found it can distinguish such things by providing a flag when calling ResolveProperty callback. Do you have any idea on this issue? How can I implement such behavior based on current API? Regards James Su ___ webkit-dev mailing list webkit-dev@lists.webkit.org http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
Re: [webkit-dev] A question regarding to JavaScriptCore's C/C++ API.
Hi Zhe. I'm developing an application which uses webkit's JavaScriptCore and a customized global object (by providing a special class when creating the context). My customized global object provides some built-in properties that can be accessed by javascript code. Now, I want to support a special behavior: allows javascript code to override a built-in property of global object by using variable declaraction statement. For example, assuming the global object has a built-in property, named foo, a var foo; statement shall create a javascript variable, named foo and the original built-in foo shall be overrid by this new javascript variable. But if there is no var foo; statement, the built-in foo shall be able to get and set from javascript code. Now the problem is, current JavaScriptCore's C API (especially those HasProperty, GetProperty, SetProperty callbacks of a class definition) can't distinguish variable delcaration statement and variable assigment statement. I checked SpiderMonkey's API and found it can distinguish such things by providing a flag when calling ResolveProperty callback. I'm surprised to hear that SpiderMonkey's property setting API includes a flag distinguishing var declarations from other kinds of property setting. Internet Explorer supports shadowing global properties with var declarations, but Firefox does not. (Perhaps you're thinking of the SpiderMonkey flag to distinguish x = y syntax from this.x = y syntax, which is slightly different.) It may not be my place, but I would discourage you from giving var declarations a special behavior, distinct from their behavior on the web. Much of the value of JavaScript derives from the fact that so many programmers understand how it works, due to their experience with the web. Do you have any idea on this issue? How can I implement such behavior based on current API? There is no API in JavaScriptCore for distinguishing between var and other property setting. I'm not sure how you would implement that. Geoff ___ webkit-dev mailing list webkit-dev@lists.webkit.org http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
Re: [webkit-dev] A question regarding to JavaScriptCore's C/C++ API.
Thanks for your reply. On Sat, Mar 7, 2009 at 7:41 AM, Geoffrey Garen gga...@apple.com wrote: Hi Zhe. I'm developing an application which uses webkit's JavaScriptCore and a customized global object (by providing a special class when creating the context). My customized global object provides some built-in properties that can be accessed by javascript code. Now, I want to support a special behavior: allows javascript code to override a built-in property of global object by using variable declaraction statement. For example, assuming the global object has a built-in property, named foo, a var foo; statement shall create a javascript variable, named foo and the original built-in foo shall be overrid by this new javascript variable. But if there is no var foo; statement, the built-in foo shall be able to get and set from javascript code. Now the problem is, current JavaScriptCore's C API (especially those HasProperty, GetProperty, SetProperty callbacks of a class definition) can't distinguish variable delcaration statement and variable assigment statement. I checked SpiderMonkey's API and found it can distinguish such things by providing a flag when calling ResolveProperty callback. I'm surprised to hear that SpiderMonkey's property setting API includes a flag distinguishing var declarations from other kinds of property setting. Internet Explorer supports shadowing global properties with var declarations, but Firefox does not. (Perhaps you're thinking of the SpiderMonkey flag to distinguish x = y syntax from this.x = y syntax, which is slightly different.) SpiderMonkey can distinguish among many different type of statements. See https://developer.mozilla.org/En/SpiderMonkey/JSAPI_Reference/JSNewResolveOp It may not be my place, but I would discourage you from giving var declarations a special behavior, distinct from their behavior on the web. Much of the value of JavaScript derives from the fact that so many programmers understand how it works, due to their experience with the web. I also don't want to support such non-standard behavior, however we need support legacy javascript code written for windows which rely on this behavior. What a pity. Anyway, thanks for your reply. Do you have any idea on this issue? How can I implement such behavior based on current API? There is no API in JavaScriptCore for distinguishing between var and other property setting. I'm not sure how you would implement that. JavaScriptCore's API is simple and easy to use, however in most cases, it's too simple to achieve some feature, comparing to SpiderMonkey, which is too complex and flexible. Geoff ___ webkit-dev mailing list webkit-dev@lists.webkit.org http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
[webkit-dev] A question regarding to JavaScriptCore's C/C++ API.
Hi, I'm developing an application which uses webkit's JavaScriptCore and a customized global object (by providing a special class when creating the context). My customized global object provides some built-in properties that can be accessed by javascript code. Now, I want to support a special behavior: allows javascript code to override a built-in property of global object by using variable declaraction statement. For example, assuming the global object has a built-in property, named foo, a var foo; statement shall create a javascript variable, named foo and the original built-in foo shall be overrid by this new javascript variable. But if there is no var foo; statement, the built-in foo shall be able to get and set from javascript code. Now the problem is, current JavaScriptCore's C API (especially those HasProperty, GetProperty, SetProperty callbacks of a class definition) can't distinguish variable delcaration statement and variable assigment statement. I checked SpiderMonkey's API and found it can distinguish such things by providing a flag when calling ResolveProperty callback. Do you have any idea on this issue? How can I implement such behavior based on current API? Regards James Su ___ webkit-dev mailing list webkit-dev@lists.webkit.org http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
