Re: [amibroker] AFL programming style questions, AmiBroker Email List Archive

On Aug 2, 2008, at 3:58 AM, Herman vandenBergen wrote:

I have tried many styles but was never able to stick to anyone. Here are some of my preferences however i am afraid I don't have a specific style.

I like compact listings to see the maximum number of lines at once.

1. Ditto.

I rarely use multiple statements in one line.

2. I do this sometimes when it expresses one thought like: if( Condition ){ X=This; Y=That; }

I use empty lines to space functional blocks, not to space code for visual effect.

3. Ditto.

I like to indent the curly brackets, to make function and other blocks of code stand out better

4. I do this type of code block indenting now:

if(condition){ // simple comment about what we are doing

indented block of code

is put here

}

else{ // another simple comment

the else part

}

I use include files when I can to shorten listings. i frequently paste the code temporarily back in for debugging.

5. Ditto. I have thought it would be cool if include files could be edited and applied with the syntax check in context with the active chart --dream on.

If I need to store a lot of calculated variables I may write them to an include file instead of using StaticVariables or persistentvariables. I use #Pragma NoCache to get it read each time.

6. This is a real out of the box idea that never occurred to me. So you overwrite a file with lines of text like "var = number; " then pull them in at the beginning of your formula as a way of saving parameters. I approached the problem differently with Flexible Parameters, but I like your idea to let the AFL parse the names and default values in this way.

I use long descriptive variable names; its usually less typing and easier to read than adding long comments.

7. I am trying to do more of this.

I break up lengthy calculations to give me debugging points.

8. Ditto.

I use DebugView a lot, every day.

9. Never use it other than once long ago. I have now written special debug statements that display variables (in an information "button" array) as they appear at any selected bar in a loop, or anytime option. This has made debugging hard problems a lot easier now. However, I can see that for things like an auto trade audit trail, the DebugView method is the way to go.

I use three //////// rows to separate major functional sections to allow spotting them when scrolling through thousands of lines of code.

10. Ditto, but I use //==============

I key most static variables to prevent them from being common to multiple applications

11. Ditto, but I only use ChartID because I only have one chart per ID.

I use persistent variables to facilitate easy start up sequences and to keep trading (IB/TWS) records

12. Ditto, but I use Flexible Parameters method for this.

I like to see initialization blocks because conditions often change

13. Ditto.

I have folders in my Charts workspace that contain frequent used code snippets, segments, templates, etc. I edit-copy-paste from these

14. Good idea.

I often work with two editor windows, one to copy from, one current work

15. Ditto, but one is often a Mac window and one a PC window. ;-)

I Apply my include files to a separate pane/tab so I can easily open/modify include files. i use 20 tabs.

16. Interesting idea. Some of my include files will not compile without each other.

I use Chart tabs to organize work in progress and create Layouts for major code changes, or new systems.

17. I only do a little of this.

I use revision numbers for all programs, like ProgramName-001. This creates lots of files and requires me to run Program maintenance once a week.

18. I could improve in this area. I usually just keep the last one -- though I have an automatic backup system that keeps versions by time, date and month.

Once a week I search my computer for all afl files and import them into dated-folders in InfoSelect.

19. Luckily, I only have a few programs and only only one main AFL I work on, so it is not hard for me to track my stuff.

When assigning many variables I like to tab all the "=" signs to the same level for easier reading.

20. That is an interesting idea.

...

best regards,
herman

Friday, August 1, 2008, 9:07:31 PM, you wrote:

> Hello veteran AFL programmers,

> I am still working on developing a consistent AFL style.

> I am writing a lot of AFL functions. I try to make as many things
> functions as I can so that I can reuse a lot of code. It also makes
> it easier for the editor to find syntax errors since my main code is
> indicator only and the syntax check pass does not see that code since
> it runs without the Chart ID.

> My trading platform is over 5000 lines of AFL (I keep adding more, and
> it keeps getting smaller...LOL). About half of that is functions. I
> pass a lot of data through global variables and arrays between
> functions for the state of the system. It was the only efficient way
> that I knew how to make code modular was to have the data common. AFL
> is largely based on that premise already with special state variables
> and price/trade arrays.

> Right now, I have a mix of variable initializations and just global
> declarations at the top of the formula so that I don't have to declare
> the globals in each function. I still have a lot of global
> declarations in some functions, but I want to finish getting rid of
> them and just have them declared at the top with a good description of
> how they are used.

> I had it in my head that a bunch of global declarations in a
> frequently called function would slow down the execution of the
> function. Am I right about that?
> I thought I could just mention the names of the input and output
> variables in the header comments if needed for documentation.

> I am also slowly changing my comments from // to /* */ so that they
> are not in the execution path.

> I am starting to make my variable names longer so that they are more
> descriptive of the data they hold.

> I have some naming conventions like FP_Name for variables that are
> part of my Flexible Parameters system and exist outside of that module.

> I am now planning on adding GP_Name for global parameter names and
> SP_Name for symbol specific parameter names. In Flexible Parameters,
> I give my parameters distinct names independent of their displayed
> labels. Those will be more than mere convention in that they will
> cause the parameters to be saved in a different file folder.

> What kind of naming conventions do you use that you are proud of?

> Any other unique features of your program style that you think are
> worth copying?

> Thanks for sharing your style ideas.

> Best regards,
> Dennis