override function and keep arguments

[tommedema]

Hi there,

I'm trying to overwrite a function with reflection like this:

Reflect.setField(this, methodName, function() {

field();

callbackFunc();

});

The problem is that the new function has lost the old function's parameters. How do I make sure that these are passed to the old function regardless?

Thanks.

- Tom

--
haXe - an open source web programming language
http://haxe.org

[Cauê W.]

Tom, I have the feeling that you can try looking at Reflect.makeVarArgs , but I never really used it, nor is it available to the cpp target.

2010/7/12 Tom <[hidden email]>

Hi there,

I'm trying to overwrite a function with reflection like this:

Reflect.setField(this, methodName, function() {

field();

callbackFunc();

});

The problem is that the new function has lost the old function's parameters. How do I make sure that these are passed to the old function regardless?

Thanks.

- Tom

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[tommedema]

Hi,

makeVarArgs converts a function with an array of arguments to a function with each array element as an argument.

That's not what I need unfortunately.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

Tom, I have the feeling that you can try looking at Reflect.makeVarArgs , but I never really used it, nor is it available to the cpp target.

2010/7/12 Tom <[hidden email]>

Hi there,

I'm trying to overwrite a function with reflection like this:

Reflect.setField(this, methodName, function() {

field();

callbackFunc();

});

The problem is that the new function has lost the old function's parameters. How do I make sure that these are passed to the old function regardless?

Thanks.

- Tom

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[Cauê W.]

With makeVarArgs, you can make a dynamic function that will take exactly the parameters you had on the old field, so you can pass to it.

Maybe something like this:

var oldFunc = Reflect.makeVarArgs(Reflect.field(this, methodName));
Reflect.setField(this, methodName, Reflect.makeVarArgs(function(args:Array<Dynamic> {  oldFunc(args); callbackFunc();   }));

2010/7/12 Tom <[hidden email]>

Hi,

makeVarArgs converts a function with an array of arguments to a function with each array element as an argument.

That's not what I need unfortunately.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

Tom, I have the feeling that you can try looking at Reflect.makeVarArgs , but I never really used it, nor is it available to the cpp target.

2010/7/12 Tom <[hidden email]>

Hi there,

I'm trying to overwrite a function with reflection like this:

Reflect.setField(this, methodName, function() {

field();

callbackFunc();

});

The problem is that the new function has lost the old function's parameters. How do I make sure that these are passed to the old function regardless?

Thanks.

- Tom

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[tommedema]

Hi,

I tested that and that's not what makeVarArgs seems to do.

Your code will result in all passed parameters to be passed to the first parameter.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

With makeVarArgs, you can make a dynamic function that will take exactly the parameters you had on the old field, so you can pass to it.

Maybe something like this:

var oldFunc = Reflect.makeVarArgs(Reflect.field(this, methodName));
Reflect.setField(this, methodName, Reflect.makeVarArgs(function(args:Array<Dynamic> {  oldFunc(args); callbackFunc();   }));

2010/7/12 Tom <[hidden email]>

Hi,

makeVarArgs converts a function with an array of arguments to a function with each array element as an argument.

That's not what I need unfortunately.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

Tom, I have the feeling that you can try looking at Reflect.makeVarArgs , but I never really used it, nor is it available to the cpp target.

2010/7/12 Tom <[hidden email]>

Hi there,

I'm trying to overwrite a function with reflection like this:

Reflect.setField(this, methodName, function() {

field();

callbackFunc();

});

The problem is that the new function has lost the old function's parameters. How do I make sure that these are passed to the old function regardless?

Thanks.

- Tom

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[Justin Donaldson-2]

You could look at the memoize snippet:
http://haxe.org/doc/snip/memoize

Or, you could look at a technique I called "function decoration":
http://scwn.net/2009/10/09/function-decoration-in-haxe-glue/

-Justin

On Mon, Jul 12, 2010 at 1:48 PM, Tom <[hidden email]> wrote:

Hi,

I tested that and that's not what makeVarArgs seems to do.

Your code will result in all passed parameters to be passed to the first parameter.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

With makeVarArgs, you can make a dynamic function that will take exactly the parameters you had on the old field, so you can pass to it.

Maybe something like this:

var oldFunc = Reflect.makeVarArgs(Reflect.field(this, methodName));
Reflect.setField(this, methodName, Reflect.makeVarArgs(function(args:Array<Dynamic> {  oldFunc(args); callbackFunc();   }));

2010/7/12 Tom <[hidden email]>

Hi,

makeVarArgs converts a function with an array of arguments to a function with each array element as an argument.

That's not what I need unfortunately.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

Tom, I have the feeling that you can try looking at Reflect.makeVarArgs , but I never really used it, nor is it available to the cpp target.

2010/7/12 Tom <[hidden email]>

Hi there,

I'm trying to overwrite a function with reflection like this:

Reflect.setField(this, methodName, function() {

field();

callbackFunc();

});

The problem is that the new function has lost the old function's parameters. How do I make sure that these are passed to the old function regardless?

Thanks.

- Tom

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
blog: http://www.scwn.net
aim: iujjd
twitter: jjdonald


--
haXe - an open source web programming language
http://haxe.org

[tommedema]

Basically, what I would need there is a function to convert a function's parameters to an array with each parameter. makeVarArgs does the opposite.

- Tom

2010/7/12 Tom <[hidden email]>

Hi,

I tested that and that's not what makeVarArgs seems to do.

Your code will result in all passed parameters to be passed to the first parameter.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

With makeVarArgs, you can make a dynamic function that will take exactly the parameters you had on the old field, so you can pass to it.

Maybe something like this:

var oldFunc = Reflect.makeVarArgs(Reflect.field(this, methodName));
Reflect.setField(this, methodName, Reflect.makeVarArgs(function(args:Array<Dynamic> {  oldFunc(args); callbackFunc();   }));

2010/7/12 Tom <[hidden email]>

Hi,

makeVarArgs converts a function with an array of arguments to a function with each array element as an argument.

That's not what I need unfortunately.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

Tom, I have the feeling that you can try looking at Reflect.makeVarArgs , but I never really used it, nor is it available to the cpp target.

2010/7/12 Tom <[hidden email]>

Hi there,

I'm trying to overwrite a function with reflection like this:

Reflect.setField(this, methodName, function() {

field();

callbackFunc();

});

The problem is that the new function has lost the old function's parameters. How do I make sure that these are passed to the old function regardless?

Thanks.

- Tom

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[tommedema]

I got it working I do believe:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

});

Reflect.setField(this, methodName, newFunc);

}

}

If anyone has any comments on this, eg. for improved performance, please tell me.

Thanks!

- Tom

2010/7/12 Justin Donaldson <[hidden email]>

You could look at the memoize snippet:
http://haxe.org/doc/snip/memoize

Or, you could look at a technique I called "function decoration":
http://scwn.net/2009/10/09/function-decoration-in-haxe-glue/

-Justin

On Mon, Jul 12, 2010 at 1:48 PM, Tom <[hidden email]> wrote:

Hi,

I tested that and that's not what makeVarArgs seems to do.

Your code will result in all passed parameters to be passed to the first parameter.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

With makeVarArgs, you can make a dynamic function that will take exactly the parameters you had on the old field, so you can pass to it.

Maybe something like this:

var oldFunc = Reflect.makeVarArgs(Reflect.field(this, methodName));
Reflect.setField(this, methodName, Reflect.makeVarArgs(function(args:Array<Dynamic> {  oldFunc(args); callbackFunc();   }));

2010/7/12 Tom <[hidden email]>

Hi,

makeVarArgs converts a function with an array of arguments to a function with each array element as an argument.

That's not what I need unfortunately.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

Tom, I have the feeling that you can try looking at Reflect.makeVarArgs , but I never really used it, nor is it available to the cpp target.

2010/7/12 Tom <[hidden email]>

Hi there,

I'm trying to overwrite a function with reflection like this:

Reflect.setField(this, methodName, function() {

field();

callbackFunc();

});

The problem is that the new function has lost the old function's parameters. How do I make sure that these are passed to the old function regardless?

Thanks.

- Tom

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--

blog: http://www.scwn.net
aim: iujjd
twitter: jjdonald


--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[Heinz Hölzer-2]

Your approach only works for void functions, if your function returns something you need to return the result:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

var res = Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);
                                return res;

});

Reflect.setField(this, methodName, newFunc);

}

}

Am 12.07.2010 23:07, schrieb Tom:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

});

Reflect.setField(this, methodName, newFunc);

}

}

--
haXe - an open source web programming language
http://haxe.org

[tommedema]

Thanks.

One problem I noticed is that it does not work for static functions. Apparently, Reflect.field(this, methodName) returns nothing if methodName is a static (class) method. I tried adding dynamic to the function declaration but that didn't help.

Any way to solve this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

Your approach only works for void functions, if your function returns something you need to return the result:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

var res = Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

                                return res;

});

Reflect.setField(this, methodName, newFunc);

}

}

Am 12.07.2010 23:07, schrieb Tom:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

});

Reflect.setField(this, methodName, newFunc);

}

}

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[Heinz Hölzer-2]

You need the class of your object:

Reflect.field(Type.getClass(obj), "staticmethod");



Am 12.07.2010 23:23, schrieb Tom:

Thanks.

One problem I noticed is that it does not work for static functions. Apparently, Reflect.field(this, methodName) returns nothing if methodName is a static (class) method. I tried adding dynamic to the function declaration but that didn't help.

Any way to solve this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

Your approach only works for void functions, if your function returns something you need to return the result:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

var res = Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

                                return res;

});

Reflect.setField(this, methodName, newFunc);

}

}

Am 12.07.2010 23:07, schrieb Tom:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

});

Reflect.setField(this, methodName, newFunc);

}

}

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[tommedema]

That makes sense. Thanks.

Hopefully my last issue: how would I override a constructor like this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

You need the class of your object:

Reflect.field(Type.getClass(obj), "staticmethod");



Am 12.07.2010 23:23, schrieb Tom:

Thanks.

One problem I noticed is that it does not work for static functions. Apparently, Reflect.field(this, methodName) returns nothing if methodName is a static (class) method. I tried adding dynamic to the function declaration but that didn't help.

Any way to solve this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

Your approach only works for void functions, if your function returns something you need to return the result:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

var res = Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

                                return res;

});

Reflect.setField(this, methodName, newFunc);

}

}

Am 12.07.2010 23:07, schrieb Tom:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

});

Reflect.setField(this, methodName, newFunc);

}

}

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[Heinz Hölzer-2]

I don't think that this is possible on all platforms.

for neko it works this way (but this will definitely not work for avm2):

var oldFunc = Reflect.field(Test, "new");
        Reflect.setField(Test, "new",
                Reflect.makeVarArgs(function(args : Array<Dynamic>)
                { 
                            trace("before");
                            var result = Reflect.callMethod(Test, oldFunc, args);
                            trace("result: " + result);
                            trace("after");
                            return result;
                } ));



Am 12.07.2010 23:58, schrieb Tom:

That makes sense. Thanks.

Hopefully my last issue: how would I override a constructor like this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

You need the class of your object:

Reflect.field(Type.getClass(obj), "staticmethod");



Am 12.07.2010 23:23, schrieb Tom:

Thanks.

One problem I noticed is that it does not work for static functions. Apparently, Reflect.field(this, methodName) returns nothing if methodName is a static (class) method. I tried adding dynamic to the function declaration but that didn't help.

Any way to solve this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

Your approach only works for void functions, if your function returns something you need to return the result:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

var res = Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

                                return res;

});

Reflect.setField(this, methodName, newFunc);

}

}

Am 12.07.2010 23:07, schrieb Tom:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

});

Reflect.setField(this, methodName, newFunc);

}

}

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[tommedema]

Is it not possible to retrieve the constructor function of a class?

- Tom

2010/7/13 Heinz Hölzer <[hidden email]>

I don't think that this is possible on all platforms.

for neko it works this way (but this will definitely not work for avm2):

var oldFunc = Reflect.field(Test, "new");
        Reflect.setField(Test, "new",

                Reflect.makeVarArgs(function(args : Array<Dynamic>)
                { 

                            trace("before");
                            var result = Reflect.callMethod(Test, oldFunc, args);
                            trace("result: " + result);
                            trace("after");
                            return result;
                } ));



Am 12.07.2010 23:58, schrieb Tom:

That makes sense. Thanks.

Hopefully my last issue: how would I override a constructor like this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

You need the class of your object:

Reflect.field(Type.getClass(obj), "staticmethod");



Am 12.07.2010 23:23, schrieb Tom:

Thanks.

One problem I noticed is that it does not work for static functions. Apparently, Reflect.field(this, methodName) returns nothing if methodName is a static (class) method. I tried adding dynamic to the function declaration but that didn't help.

Any way to solve this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

Your approach only works for void functions, if your function returns something you need to return the result:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

var res = Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

                                return res;

});

Reflect.setField(this, methodName, newFunc);

}

}

Am 12.07.2010 23:07, schrieb Tom:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

});

Reflect.setField(this, methodName, newFunc);

}

}

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

[Justin Donaldson-2]

Hi Tom,

If you look at the Glue class, this is essentially what is going on. You can access the original arguments of a function, and even preserve the type if you need to.  Or, you can just put them in an array.

Say you have a (dynamic) static/member function foo() that looks like:

foo(x,y,z) : Int;

you can write a quick helper function:

var f = function(x,y,z) { trace([x, y, z]); } // here's your parameters in an array.

and then "glue" it to the foo function as follows:

foo = Glue.join3(foo, f);

foo(1,2,3) now will call the f function as a side effect with the same arguments.  Through the f function, you can access the original arguments... trace them, etc.  The main benefit here is that typing and arity are preserved.  Writing the helper function f() ensures that you are typing the arguments correctly, letting you safely do more sophisticated things with them.  Variations of the Glue class will let you interrupt or overload the original method process, if that's what you want to do.

-Justin

On Mon, Jul 12, 2010 at 1:54 PM, Tom <[hidden email]> wrote:

Basically, what I would need there is a function to convert a function's parameters to an array with each parameter. makeVarArgs does the opposite.

- Tom

2010/7/12 Tom <[hidden email]>

Hi,

I tested that and that's not what makeVarArgs seems to do.

Your code will result in all passed parameters to be passed to the first parameter.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

With makeVarArgs, you can make a dynamic function that will take exactly the parameters you had on the old field, so you can pass to it.

Maybe something like this:

var oldFunc = Reflect.makeVarArgs(Reflect.field(this, methodName));
Reflect.setField(this, methodName, Reflect.makeVarArgs(function(args:Array<Dynamic> {  oldFunc(args); callbackFunc();   }));

2010/7/12 Tom <[hidden email]>

Hi,

makeVarArgs converts a function with an array of arguments to a function with each array element as an argument.

That's not what I need unfortunately.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

Tom, I have the feeling that you can try looking at Reflect.makeVarArgs , but I never really used it, nor is it available to the cpp target.

2010/7/12 Tom <[hidden email]>

Hi there,

I'm trying to overwrite a function with reflection like this:

Reflect.setField(this, methodName, function() {

field();

callbackFunc();

});

The problem is that the new function has lost the old function's parameters. How do I make sure that these are passed to the old function regardless?

Thanks.

- Tom

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
blog: http://www.scwn.net
aim: iujjd
twitter: jjdonald


--
haXe - an open source web programming language
http://haxe.org

[tommedema]

Hi Justin,

I got that far yes. The only issue I have now is overriding constructor functions.

- Tom

2010/7/13 Justin Donaldson <[hidden email]>

Hi Tom,

If you look at the Glue class, this is essentially what is going on. You can access the original arguments of a function, and even preserve the type if you need to.  Or, you can just put them in an array.

Say you have a (dynamic) static/member function foo() that looks like:

foo(x,y,z) : Int;

you can write a quick helper function:

var f = function(x,y,z) { trace([x, y, z]); } // here's your parameters in an array.

and then "glue" it to the foo function as follows:

foo = Glue.join3(foo, f);

foo(1,2,3) now will call the f function as a side effect with the same arguments.  Through the f function, you can access the original arguments... trace them, etc.  The main benefit here is that typing and arity are preserved.  Writing the helper function f() ensures that you are typing the arguments correctly, letting you safely do more sophisticated things with them.  Variations of the Glue class will let you interrupt or overload the original method process, if that's what you want to do.

-Justin

On Mon, Jul 12, 2010 at 1:54 PM, Tom <[hidden email]> wrote:

Basically, what I would need there is a function to convert a function's parameters to an array with each parameter. makeVarArgs does the opposite.

- Tom

2010/7/12 Tom <[hidden email]>

Hi,

I tested that and that's not what makeVarArgs seems to do.

Your code will result in all passed parameters to be passed to the first parameter.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

With makeVarArgs, you can make a dynamic function that will take exactly the parameters you had on the old field, so you can pass to it.

Maybe something like this:

var oldFunc = Reflect.makeVarArgs(Reflect.field(this, methodName));
Reflect.setField(this, methodName, Reflect.makeVarArgs(function(args:Array<Dynamic> {  oldFunc(args); callbackFunc();   }));

2010/7/12 Tom <[hidden email]>

Hi,

makeVarArgs converts a function with an array of arguments to a function with each array element as an argument.

That's not what I need unfortunately.

- Tom

2010/7/12 Cauê Waneck <[hidden email]>

Tom, I have the feeling that you can try looking at Reflect.makeVarArgs , but I never really used it, nor is it available to the cpp target.

2010/7/12 Tom <[hidden email]>

Hi there,

I'm trying to overwrite a function with reflection like this:

Reflect.setField(this, methodName, function() {

field();

callbackFunc();

});

The problem is that the new function has lost the old function's parameters. How do I make sure that these are passed to the old function regardless?

Thanks.

- Tom

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[Justin Donaldson-2]

It's possible in javascript through overriding/setting the prototype + constructor.  Php would need to override __construct (I think), and neko the field "new".  I'm not really sure what is possible with C++.  It's impossible in flash afaik.

So, unfortunately your best bet is trying to implement this through target specific magic (hopefully you're not using flash). 
http://haxe.org/doc/advanced/magic?lang=en

-Justin

On Mon, Jul 12, 2010 at 4:05 PM, Tom <[hidden email]> wrote:

Is it not possible to retrieve the constructor function of a class?

- Tom

2010/7/13 Heinz Hölzer <[hidden email]>

I don't think that this is possible on all platforms.

for neko it works this way (but this will definitely not work for avm2):

var oldFunc = Reflect.field(Test, "new");
        Reflect.setField(Test, "new",

                Reflect.makeVarArgs(function(args : Array<Dynamic>)
                { 

                            trace("before");
                            var result = Reflect.callMethod(Test, oldFunc, args);
                            trace("result: " + result);
                            trace("after");
                            return result;
                } ));



Am 12.07.2010 23:58, schrieb Tom:

That makes sense. Thanks.

Hopefully my last issue: how would I override a constructor like this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

You need the class of your object:

Reflect.field(Type.getClass(obj), "staticmethod");



Am 12.07.2010 23:23, schrieb Tom:

Thanks.

One problem I noticed is that it does not work for static functions. Apparently, Reflect.field(this, methodName) returns nothing if methodName is a static (class) method. I tried adding dynamic to the function declaration but that didn't help.

Any way to solve this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

Your approach only works for void functions, if your function returns something you need to return the result:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

var res = Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

                                return res;

});

Reflect.setField(this, methodName, newFunc);

}

}

Am 12.07.2010 23:07, schrieb Tom:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

});

Reflect.setField(this, methodName, newFunc);

}

}

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[tommedema]

I am using flash aswell as Javascript.

Anyway, I'll tell the programmer to add this functionality through initializers:

public function new() {

init();

}

private function init() {

    //actual constructor

}

Then you can bind to the init method.

- Tom

2010/7/13 Justin Donaldson <[hidden email]>

It's possible in javascript through overriding/setting the prototype + constructor.  Php would need to override __construct (I think), and neko the field "new".  I'm not really sure what is possible with C++.  It's impossible in flash afaik.

So, unfortunately your best bet is trying to implement this through target specific magic (hopefully you're not using flash). 
http://haxe.org/doc/advanced/magic?lang=en

-Justin

On Mon, Jul 12, 2010 at 4:05 PM, Tom <[hidden email]> wrote:

Is it not possible to retrieve the constructor function of a class?

- Tom

2010/7/13 Heinz Hölzer <[hidden email]>

I don't think that this is possible on all platforms.

for neko it works this way (but this will definitely not work for avm2):

var oldFunc = Reflect.field(Test, "new");
        Reflect.setField(Test, "new",

                Reflect.makeVarArgs(function(args : Array<Dynamic>)
                { 

                            trace("before");
                            var result = Reflect.callMethod(Test, oldFunc, args);
                            trace("result: " + result);
                            trace("after");
                            return result;
                } ));



Am 12.07.2010 23:58, schrieb Tom:

That makes sense. Thanks.

Hopefully my last issue: how would I override a constructor like this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

You need the class of your object:

Reflect.field(Type.getClass(obj), "staticmethod");



Am 12.07.2010 23:23, schrieb Tom:

Thanks.

One problem I noticed is that it does not work for static functions. Apparently, Reflect.field(this, methodName) returns nothing if methodName is a static (class) method. I tried adding dynamic to the function declaration but that didn't help.

Any way to solve this?

- Tom

2010/7/12 Heinz Hölzer <[hidden email]>

Your approach only works for void functions, if your function returns something you need to return the result:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

var res = Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

                                return res;

});

Reflect.setField(this, methodName, newFunc);

}

}

Am 12.07.2010 23:07, schrieb Tom:

public function aop_objBindAfter(methodName:String, callbackFunc:Dynamic):Void {

var field:Dynamic = Reflect.field(this, methodName);

if (field != null) {

var me:Feature = this;

var newFunc:Dynamic = Reflect.makeVarArgs(function(args:Array<Dynamic>) {

Reflect.callMethod(me, field, args);

Reflect.callMethod(me, callbackFunc, args);

});

Reflect.setField(this, methodName, newFunc);

}

}

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http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--
haXe - an open source web programming language
http://haxe.org

--

blog: http://www.scwn.net
aim: iujjd
twitter: jjdonald

--
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http://haxe.org

--
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