Check out Alice Chess, our featured variant for June, 2024.

Enter Your Reply

The Comment You're Replying To

Aurelian Florea wrote on Tue, Apr 7, 2020 05:52 AM UTC:

Unfortuneatly the code you proposed does not work either. It gives false pozitives when displaying (shows all camel and knight moves) but on the other hand, the special 1st time moves are considered wrong when applied. My guess is that then it is a deeper problem as the king is not a ordinary piece and changing it's properties could impact other subroutines in less predictable ways.

I have not changed the code to use flags because yesterday I was a little busy with other things, but I doubt this impacted the overall result, althought a slower speed was to be expected. Thanks for your help Fergus, but it seems that apothecary chess is to difficult for me to program at this time, so I'm considerring taking a break from programming presets.

Edit Form

Comment on the page The Fairychess Include File Tutorial

Name or UserID: Password: if signing in with UserIDRating: Comment or question:
Format:

Conduct Guidelines

This is a Chess variants website, not a general forum.: Please limit your comments to Chess variants or the operation of this site.
Keep this website a safe space for Chess variant hobbyists of all stripes.: Because we want people to feel comfortable here no matter what their political or religious beliefs might be, we ask you to avoid discussing politics, religion, or other controversial subjects here. No matter how passionately you feel about any of these subjects, just take it someplace else.
Avoid Inflammatory Comments: If you are feeling anger, keep it to yourself until you calm down. Avoid insulting, blaming, or attacking someone you are angry with. Focus criticisms on ideas rather than people, and understand that criticisms of your ideas are not personal attacks and do not justify an inflammatory response.

Quick Markdown Guide

By default, new comments may be entered as Markdown, simple markup syntax designed to be readable and not look like markup. Comments stored as Markdown will be converted to HTML by Parsedown before displaying them. This follows the Github Flavored Markdown Spec with support for Markdown Extra. For a good overview of Markdown in general, check out the Markdown Guide. Here is a quick comparison of some commonly used Markdown with the rendered result:

# Top level header: `<H1>`

> Block quote 
>
> Second paragraph in block quote

First Paragraph of response. *Italics*, **bold**, and ***bold italics***.

Second Paragraph after blank line. Here is some <U>HTML code</U> mixed in with the Markdown, and here is the same `<U>HTML code</U>` enclosed by backticks.

## Secondary Header: `<H2>`

* Unordered list item
* Second unordered list item
+ New unordered list
    * Nested list item
- An URL by itself:
    + https://www.chessvariants.com
- A text link:
    - [The Chess Variant Pages](https://www.chessvariants.com)

### Third Level header `<H3>`
	
1. An ordered list item.
1. A second ordered list item with the same number.
2. A third ordered list item.

~~~
Here is some preformatted text.
  This line begins with some indentation.
    This begins with even more indentation.
And this line has no indentation.
~~~

![Alt text for a graphic image](/graphics.dir/cvp-logo-draft8.png)

A definition list
: A list of terms, each with one or more definitions following it.
: An HTML construct using the tags `<DL>`, `<DT>` and `<DD>`.

A term
: Its definition after a colon.
: A second definition.
: A third definition.

Another term following a blank line
: The definition of that term.

Top level header: `<H1>`

Block quote

Second paragraph in block quote

First Paragraph of response. Italics, bold, and bold italics.

Second Paragraph after blank line. Here is some HTML code mixed in with the Markdown, and here is the same <U>HTML code</U> enclosed by backticks.

Secondary Header: `<H2>`

Unordered list item
Second unordered list item

New unordered list
- Nested list item

An URL by itself:
- https://www.chessvariants.com
A text link:
- The Chess Variant Pages

Third Level header `<H3>`

An ordered list item.
A second ordered list item with the same number.
A third ordered list item.

Here is some preformatted text.
  This line begins with some indentation.
    This begins with even more indentation.
And this line has no indentation.

A definition list: A list of terms, each with one or more definitions following it.; An HTML construct using the tags <DL>, <DT> and <DD>.
A term: Its definition after a colon.; A second definition.; A third definition.
Another term following a blank line: The definition of that term.

Credits

Author: Fergus Duniho.

Comments

The Fairychess Include File Tutorial. How to use the fairychess include file to program games for Game Courier.

🕸📝Fergus Duniho wrote on Mon, May 13 02:20 AM UTC in reply to Fergus Duniho from Sun May 12 10:29 PM:

I was thinking of splitting the checked function into separate checked-real and checked-potential functions, but as I was looking into which would be which, it looked like there was never any time when it was passed an empty space after the King just moved. In the Pre-Move sections, kpos or Kpos would be updated before calling the function, and in stalemated, it would check whether the King was the moving piece and pass the King's new position if it was. This meant I could reduce the function to this:

def checked anytrue lambda (fn const alias #0 var key var king) 
cond isupper space var king (onlylower) (onlyupper) 
=movetype CHECK 
=king;

Just in case, I ran this code in Ultima as a test:

sub checked king:
  my from piece;
  local movetype;

  set movetype CHECK;
  if empty var king:
    die "The King space at {#king} is empty.";
  endif;
  if isupper cond empty var king $moved space var king:
    def enemies onlylower;
  else:
    def enemies onlyupper;
  endif;
  for (from piece) fn enemies:
    if fn const alias #piece #from var king:
      return #from;
    endif;
  next;
  return false;
endsub;
def checked sub checked #0;

This code would exit right away with an error message if the subroutine, which was called by the function here, got passed an empty space. I then looked at completed games using the same include file, and they did not exit with the error message. So, I got rid of this code and modified the function, tested Ultima again, and it still worked for both actual checks and for moves that would move the King into check.

With that change made, I ran the speed tests again and got these results:

Elapsed time: 1.0438919067383 seconds

Elapsed time: 0.46452307701111 seconds

Elapsed time: 1.013090133667 seconds

Elapsed time: 0.48957395553589 seconds

Elapsed time: 1.1313791275024 seconds

Elapsed time: 0.49660110473633 seconds

In each pair the subroutine is first, and the function is second, and in each case the function takes less than half the time. In both this case and the previous one, these tests were done on the opening position in Chess, in which the King is not in check, meaning that it checks for check from every enemy piece without exiting early.

🕸📝Fergus Duniho wrote on Sun, May 12 10:29 PM UTC:

The changes to Game Courier I described here were for the purpose of writing a checked function that would do the same job as the checked subroutine but even faster. This is for the sake of illustrating the gains in speed of using functions rather than subroutines when a function will do the job. Here's the code for the subroutine and the function:

sub checked king:
    my from piece;
    local movetype;

    set movetype CHECK;
    if isupper cond empty var king $moved space var king:
        def enemies onlylower;
    else:
        def enemies onlyupper;
    endif;
    for (from piece) fn enemies:
        if fn const alias #piece #from var king:
            return #from;
        endif;
    next;
    return false;
endsub;

def checked anytrue lambda (fn const alias #0 var key var king) 
cond isupper cond empty var king $moved space var king (onlylower) (onlyupper) 
=movetype CHECK 
=king;

I have tested the function out in Ultima, because its stalemated subroutine is not widely used in other presets, and its piece functions make use of the movetype value to determine whether it is a regular move or a checking move. Things appear to be working in Ultima. In speed tests comparing 1000 repetitions of each, the function is around twice as fast. In these results, the first, third, and fifth are the subroutine, and the second, fourth, and sixth are the function.

Elapsed time: 0.92847084999084 seconds

Elapsed time: 0.45569705963135 seconds

Elapsed time: 0.87418103218079 seconds

Elapsed time: 0.46827101707458 seconds

Elapsed time: 1.1367251873016 seconds

Elapsed time: 0.65254402160645 seconds

🕸📝Fergus Duniho wrote on Thu, Apr 11 01:02 AM UTC in reply to Daniel Zacharias from Wed Apr 10 11:51 PM:

I still don't get why the previous way wasn't working since I wasn't changing the pawn subroutine which seems to modify promotion options before the last rank.

The Pawn subroutines are only for actual moves, but nothing was being done to handle variable values of wprom or bprom for potential moves. The stalemated subroutine was supposed to provide a list of all legal moves, but it was omitting moves where someone declines promoting a Pawn. By having functions that dynamically calculate what a piece may promote to, it is now able to provide an accurate list of legal moves for games with variable promotion rules, such as Gross Chess has.

Anyway, this reveals another, but more minor, problem, which is that when a pawn gets to the promotion zone the text in the option selection box is large enough that the lines overlap slightly.

I increased the line-height and made some changes to the borders.

🕸📝Fergus Duniho wrote on Thu, Apr 11 12:33 AM UTC in reply to Fergus Duniho from Wed Apr 10 07:57 PM:

For Obento Chess, you might use functions like these:

def White_Pawn-Promote elem - rank #0 9 ((FP) (FP) (F));
def Black_Pawn-Promote elem rank #0 ((f) (fp) (fp));

That should be this:

def White_Pawn-Promote elem - rank #0 9 ((F P) (F P) (F));
def Black_Pawn-Promote elem rank #0 ((f) (f p) (f p));

Daniel Zacharias wrote on Wed, Apr 10 11:51 PM UTC in reply to Fergus Duniho from 07:57 PM:

Thank you, that does work better; although I still don't get why the previous way wasn't working since I wasn't changing the pawn subroutine which seems to modify promotion options before the last rank.

Anyway, this reveals another, but more minor, problem, which is that when a pawn gets to the promotion zone the text in the option selection box is large enough that the lines overlap slightly.

List all comments and ratings for this item.

Add a comment or rating for this item.

The Chess Variant Pages is an amateur, hobbyist website that has been run by volunteers since it was founded in 1995. It focuses on documenting games based on, related to, or similar enough to Chess and on letting you play many of them.

Who What When Where Why Which How

Privacy

Operating expenses are covered through advertising and donations. Help out by making a PayPal donation or by shopping with these affiliate links:

https://www.chessvariants.org/index/editcomment.php
First Created: Sunday, March 29th, 2020
Last Modified: Friday, June 26th, 2020
File Timestamp: Wed, 06 Mar 2024 22:23:38 +0000
[info] [links] [edit]

Enter Your Reply

Top level header: <H1>

Secondary Header: <H2>

Third Level header <H3>

Top level header: `<H1>`

Secondary Header: `<H2>`

Third Level header `<H3>`