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The point is that you don't need to include thousands of expressions
but only ONE !
If you change the CONTENT of include file dynamically by writing TO the file you can
have dynamic expression evaluation.
And all that without any DLL.
Also it all really depends on what you are specifically trying to do.
General descriptions lack clarity. You need to provide ENTIRE idea with details
if you want help. Otherwise people are guessing what you are trying to do.
For example if you want to SWITCH between different conditions in run time
the SWITCH structure gives fastest execution:
switch( n )
{
case 1:
result = MA(C, 12) > C5 AND MA(C,20) < Close;
break;
case 2:
result = MA(H, 50) < C12 AND EMA(L, 12) < Close;
break;
default:
break;
}
It is fast because on ONE of Nth expressions will be actually evaluated.
There are other techniques that lead to compact and fast formula
but it ALL depends on details on what exactly you want to do.
For example I can see that your expressions are repeated with only
minor fluctuations (replacing C with H) and that can be easily wrapped
into functions / switch statements provided one has clear idea
and knows what he wants to achieve and prepares plan for that.
The general rule is first THINK a lot before writing the very first line of code.
If you begin with just typing thousands of lines of code without planning first you end up with spaghetti.
Best regards,
Tomasz Janeczko
amibroker.com
----- Original Message -----
From: "ozzyapeman" <zoopfree@xxxxxxxxxxx>
To: <amibroker@xxxxxxxxxxxxxxx>
Sent: Thursday, November 27, 2008 1:07 AM
Subject: [amibroker] Re: How to convert a string to non-string characters?!
> Thanks, TJ. Looks like I am back at square one. I contracted to have
> the DLL coded because pasting the thousands of expressions at once
> into the formula slowed down AB considerably. Most of the time it
> hung. So I was trying to generate the expressions dynamically.
>
> Correct me if I am wrong, but wouldn't the #include function result in
> overall execution that is slower than pasting the thousands of AFL
> expressions directly into the formula?
>
> Or will it actually be faster than a copy and paste?
>
> In some cases I am trying to evaluate tens of thousands of full blown
> AFL expressions per formula.
>
>
> --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@xxx> wrote:
>>
>> Hello,
>>
>> You need to understand that you are attempting to PARSE expressions.
>>
>> The only way to parse actual full-blown AFL expressions is to
> INCLUDE them
>> in the formula.
>>
>> If you want to "create" expressions on the fly AND execute them,
>> you need to take two step approach
>> a) create TEXT file with actual expressions you want to parse
>> b) #include that text file
>>
>> #pragma nocache
>> #include "the_file_with_the_expressions_to_parse"
>>
>> in the actual formula and run it.
>>
>> Best regards,
>> Tomasz Janeczko
>> amibroker.com
>> ----- Original Message -----
>> From: "ozzyapeman" <zoopfree@xxx>
>> To: <amibroker@xxxxxxxxxxxxxxx>
>> Sent: Thursday, November 27, 2008 12:38 AM
>> Subject: [amibroker] Re: How to convert a string to non-string
> characters?!
>>
>>
>> > TJ,
>> >
>> > Thanks, quick question:
>> >
>> > I gave the arithmetic expression as a quick trivial example. But what
>> > I really want to do is create and evaluate expressions of the type:
>> >
>> > Condition1 = MA(C, 12) > C5 AND MA(C,20) < Close;
>> >
>> > so for the above case, would you also recommend writing a
>> > parser/interpreter - or did you suggest that purely for arithmetic
>> > expressions like "1 + 2 + 3"?
>> >
>> >
>> > --- In amibroker@xxxxxxxxxxxxxxx, "Tomasz Janeczko" <groups@> wrote:
>> >>
>> >> You do not want to convert from string to number.
>> >> What you really want is to EVALUATE arithmetic expressions !
>> >> For that you need to either write parser/interpreter or use
>> > external onee
>> >> Thanks to AmiBroker JScript support you can use for example JScript
>> > eval function.
>> >>
>> >>
>> >> EnableScript("JScript");
>> >> <%
>> >>
>> >> %>
>> >>
>> >> function Evaluate( text )
>> >> {
>> >> so = GetScriptObject();
>> >> return so.eval( text );
>> >> }
>> >>
>> >> "The result is " + Evaluate("3 + 2");
>> >>
>> >> Best regards,
>> >> Tomasz Janeczko
>> >> amibroker.com
>> >> ----- Original Message -----
>> >> From: ozzyapeman
>> >> To: amibroker@xxxxxxxxxxxxxxx
>> >> Sent: Wednesday, November 26, 2008 11:46 PM
>> >> Subject: [amibroker] Re: How to convert a string to non-string
>> > characters?!
>> >>
>> >>
>> >> Or to take a more trivial example, the following prints "3"
>> > instead of "12":
>> >>
>> >> VarSetText("Condition1", "3 + 4 + 5");
>> >>
>> >> Total = StrToNum (VarGetText("Condition1"));
>> >>
>> >> printf ("Sum %g", Total);
>> >>
>> >> How do I convert the above string so that Total is equal to the
>> > expression itself, which is equal to 12?
>> >>
>> >>
>> >> --- In amibroker@xxxxxxxxxxxxxxx, "ozzyapeman" <zoopfree@> wrote:
>> >> >
>> >> > Yes, tried that. But since the values spit out by the function
>> > aren't
>> >> > just pure numbers, it does not seem to work.
>> >> >
>> >>
>> >
>> >
>> >
>> > ------------------------------------
>> >
>> > **** IMPORTANT ****
>> > This group is for the discussion between users only.
>> > This is *NOT* technical support channel.
>> >
>> > *********************
>> > TO GET TECHNICAL SUPPORT from AmiBroker please send an e-mail
> directly to
>> > SUPPORT {at} amibroker.com
>> > *********************
>> >
>> > For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
>> > http://www.amibroker.com/devlog/
>> >
>> > For other support material please check also:
>> > http://www.amibroker.com/support.html
>> >
>> > *********************************
>> > Yahoo! Groups Links
>> >
>> >
>> >
>>
>
>
>
> ------------------------------------
>
> **** IMPORTANT ****
> This group is for the discussion between users only.
> This is *NOT* technical support channel.
>
> *********************
> TO GET TECHNICAL SUPPORT from AmiBroker please send an e-mail directly to
> SUPPORT {at} amibroker.com
> *********************
>
> For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
> http://www.amibroker.com/devlog/
>
> For other support material please check also:
> http://www.amibroker.com/support.html
>
> *********************************
> Yahoo! Groups Links
>
>
>
------------------------------------
**** IMPORTANT ****
This group is for the discussion between users only.
This is *NOT* technical support channel.
*********************
TO GET TECHNICAL SUPPORT from AmiBroker please send an e-mail directly to
SUPPORT {at} amibroker.com
*********************
For NEW RELEASE ANNOUNCEMENTS and other news always check DEVLOG:
http://www.amibroker.com/devlog/
For other support material please check also:
http://www.amibroker.com/support.html
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