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[amibroker] Re: functions/variable scope errors



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AFL is not itself an object oriented language, though it can 
manipulate objects that have been implemented in object oriented 
languages.

I suspect that you will need to rework your code to comply with AFL 
scripting syntax, or investigate using the COM/ActiveX support to 
interact with your external objects written in C++ (or VisualBasic, 
Delphi, whatever).

http://www.amibroker.com/guide/a_aflcom.html

Mike

--- In amibroker@xxxxxxxxxxxxxxx, "loveyourenemynow" 
<loveyourenemynow@xxx> wrote:
>
> Thanks Mike,
> 
> but my code is written in such a way that functions play the roles 
of
> parameters(to avoid errors and facilitate debugging and changes),
> trying to mimic polymorphism of OO language.
> Problem is that i think functions cannot be changed at runtime 
during
> backtesting , but have to be declared one and stay the same.
> These functions return different prices (O/C) with different time
> delays so I could rewrite the code and use one functions taking 2
> paramters , one for delay and the other for O/P.
> 
> This what it comes to my mind now, but I would like to know why is 
tht
> error produced.
> what if I declare empty functions (like virtual declaration in c++) 
at
> as an empty prototype at global scope and implement and give some
> parameter dependent implementations later. Again is all about mimic
> polymorphism.
> 
> Thanks
> Ly
> 
> --- In amibroker@xxxxxxxxxxxxxxx, "Mike" <sfclimbers@> wrote:
> >
> > Read http://www.amibroker.com/guide/a_userfunctions.html
> > 
> > Then try changing your function signature to just take a 
parameter 
> > and move the declaration out of the if statement.
> > 
> > e.g.
> > function P1f(sys) {
> >   if (sys == 1) {
> >     ...
> >   }
> >   ...
> > }
> > 
> > Alternatively, you could create different functions for each 
scenario 
> > and check a condition in your calling code to determine which one 
to 
> > call.
> > 
> > e.g.
> > ...
> > if (sys == 1) {
> >   P1f();
> > } else {
> >   OtherP1f();
> > }
> > ...
> > function P1f() {
> >   ...
> > }
> > function OtherP1f() {
> >   ...
> > }
> > 
> > I don't understand your scope question. But you may find the 
> > documentation for local/global helpful:
> > 
> > http://www.amibroker.com/guide/keyword/local.html
> > http://www.amibroker.com/guide/keyword/global.html
> > 
> > Mike
> > 
> > --- In amibroker@xxxxxxxxxxxxxxx, "loveyourenemynow" 
> > <loveyourenemynow@> wrote:
> > >
> > > I am trying to optimize over diffeent types of systems and I 
need to
> > > define function accordingly, but I get and error with this code
> > > 
> > > if (sys==1){
> > > ///cc->co entry at close exit at day after open 
> > > SetOption("ActivateStopsImmediately",True);
> > > SetTradeDelays(0,0,0,0);
> > > ShortPrice=C;
> > > BuyPrice=C;
> > > CoverPrice=O;
> > > SellPrice=O;
> > > function P1f() {return Ref(C,-1);}
> > > function P2f() {return Ref(C,0);}
> > > ApplyStop(stopTypeNBar,stopModeBars,1,1); 
> > > dc=1;
> > > MaxPosPer=1;
> > > }
> > > 
> > > while outside brackets it runs.
> > > 
> > > In a similar way variable I noticed that arrays declared at 
> > different
> > > scope levels are not accessible to the lower levels (i think 
scalr
> > > yes) unless they are defined at gloabal level,
> > > This is different from c++ scope conventions.
> > > So the only way to share among different scopes (I mean 
portions of
> > > code at differnt levels of {} nesting), seems to declare them 
> > globally.
> > > Am I correct?
> > > 
> > > Thanks
> > > Ly
> > >
> >
>




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