#############################################################################
##
#W knight.g GAP 4 package `browse' Thomas Breuer
##
#############################################################################
##
#F BrowseChangeSides()
##
## <#GAPDoc Label="Knight_section">
## <Section Label="sec:knight">
## <Heading>Changing Sides</Heading>
## <Index Subkey="Changing Sides">game</Index>
##
## We consider a <M>5</M> by <M>5</M> board of squares filled with two
## types of stones, as follows. The square in the middle is left empty.
## <P/>
## <Alt Only="LaTeX"><![CDATA[
## \begin{center}
## \begin{tabular}{|c|c|c|c|c|}
## \hline
## \rule[-6pt]{0pt}{18pt}$\times$&$\times$&$\times$&$\times$&$\times$\\
## \hline
## \rule[-6pt]{0pt}{18pt}$\circ$&$\times$&$\times$&$\times$&$\times$\\
## \hline
## \rule[-6pt]{0pt}{18pt}$\circ$&$\circ$&&$\times$&$\times$\\
## \hline
## \rule[-6pt]{0pt}{18pt}$\circ$&$\circ$&$\circ$&$\circ$&$\times$\\
## \hline
## \rule[-6pt]{0pt}{18pt}$\circ$&$\circ$&$\circ$&$\circ$&$\circ$\\
## \hline
## \end{tabular}
## \end{center}
## ]]></Alt>
## <Alt Only="Text"><Verb>
## ┌───┬───┬───┬───┬───┐
## │ x │ x │ x │ x │ x │
## ├───┼───┼───┼───┼───┤
## │ o │ x │ x │ x │ x │
## ├───┼───┼───┼───┼───┤
## │ o │ o │ │ x │ x │
## ├───┼───┼───┼───┼───┤
## │ o │ o │ o │ o │ x │
## ├───┼───┼───┼───┼───┤
## │ o │ o │ o │ o │ o │
## └───┴───┴───┴───┴───┘
## </Verb></Alt>
##
## <Alt Only="HTML"> <![CDATA[
## </p><table class="sudokuin">
## <tr><td>X</td><td>X</td><td>X</td><td>X</td><td>X</td></tr>
## <tr><td>O</td><td>X</td><td>X</td><td>X</td><td>X</td></tr>
## <tr><td>O</td><td>O</td><td></td><td>X</td><td>X</td></tr>
## <tr><td>O</td><td>O</td><td>O</td><td>O</td><td>X</td></tr>
## <tr><td>O</td><td>O</td><td>O</td><td>O</td><td>O</td></tr>
## </table><p>
## ]]></Alt>
## <P/>
## The aim of the game is to exchange the two types of stones via a sequence
## of single steps that move one stone to the empty position on the board.
## Only those moves are allowed that increase or decrease one coordinate
## by <M>2</M> and increase or decrease the other by <M>1</M>;
## these are the allowed moves of the knight in chess.
## <P/>
## This game has been part of the MacTutor system <Cite Key="MacTutor"/>.
##
## <ManSection>
## <Func Name="BrowseChangeSides" Arg=""/>
##
## <Description>
## This function shows the game board in a window.
## <P/>
## Each move is encoded as a sequence of three arrow keys; there are
## <M>24</M> admissible inputs.
## <P/>
## <Example><![CDATA[
## gap> for entry in BrowseChangeSidesSolutions do
## > BrowseData.SetReplay( Concatenation( entry, "Q" ) );
## > BrowseChangeSides();
## > od;
## gap> BrowseData.SetReplay( false );
## ]]></Example>
## <P/>
## <E>Implementation remarks</E>:
## The game board is implemented via a browse table,
## without row and column labels,
## with static header, dynamic footer, and individual <C>minyx</C> function.
## Only one mode is needed,
## and besides the standard actions for quitting the table, asking for help,
## and saving the current window contents,
## only moves via combinations of the four arrow keys are admissible.
## <P/>
## The separating lines are drawn using an individual <C>SpecialGrid</C>
## function in the browse table.
## <P/>
## Some standard <Ref Func="NCurses.BrowseGeneric"/> functionality,
## such as scrolling, selecting, and searching,
## are not available in this application.
## <P/>
## The code can be found in the file <F>app/knight.g</F> of the package.
## </Description>
## </ManSection>
## </Section>
## <#/GAPDoc>
##
BindGlobal( "BrowseChangeSides", function()
local black, white, empty, m, n, upperhalf, emp, matrix, i, j,
movefunction, moves, texts, actions, help, input, grid, mode,
steps;
# Construct the cell contents.
black:= [ NCurses.attrs.BOLD, true, " x " ];
white:= [ NCurses.attrs.BOLD, true, " o " ];
empty:= "";
# Fill the matrix of formatted entries.
m:= 5;
n:= 5;
upperhalf:= Concatenation( List( [ 1 .. 5 ], j -> 2 * [ 1, j ] ),
List( [ 2 .. 5 ], j -> 2 * [ 2, j ] ),
List( [ 4 .. 5 ], j -> 2 * [ 3, j ] ),
List( [ 5 .. 5 ], j -> 2 * [ 4, j ] ) );
emp:= [ 6, 6 ];
matrix:= [];
for i in [ 2, 4 .. 2*m ] do
matrix[i]:= [];
for j in [ 2, 4 .. 2*n ] do
if [ i, j ] in upperhalf then
matrix[i][j]:= black;
else
matrix[i][j]:= white;
fi;
od;
od;
matrix[ emp[1] ][ emp[2] ]:= empty;
# Supported actions are
# - moving the free position by a knight move,
# - entering the help mode,
# - and leaving the table
movefunction:= function( twice, once )
return function( t )
local new;
# Compute the coordinate changes.
if twice mod 2 = 0 then
new:= emp + 2 * [ 2 * twice - 6, once - 2 ];
else
new:= emp + 2 * [ once - 3, 2 * twice - 4 ];
fi;
if 0 < new[1] and 0 < new[2] and
new[1] <= 2 * m and new[2] <= 2 * n then
matrix[ emp[1] ][ emp[2] ]:= matrix[ new[1] ][ new[2] ];
matrix[ new[1] ][ new[2] ]:= empty;
steps:= steps + 1;
emp:= new;
t.dynamic.changed:= true;
fi;
return t.dynamic.changed;
end;
end;
# Construct the mode.
moves:= [ NCurses.keys.LEFT, NCurses.keys.UP,
NCurses.keys.RIGHT, NCurses.keys.DOWN ];
texts:= [ "<Left>", "<Up>", "<Right>", "<Down>" ];
actions:= [];
for i in [ 1 .. 4 ] do
for j in [ 1 .. 4 ] do
if i <> j and AbsInt( i - j ) <> 2 then
help:= Concatenation( "move twice ", texts[i],
" and once ", texts[j] );
for input in [ [ i, i, j ], [ i, j, i ], [ j, i, i ] ] do
Add( actions, [ [ [ moves{ input },
Concatenation( texts{ input } ) ] ],
rec( helplines:= [ help ], action:= movefunction( i, j ) ) ] );
od;
fi;
od;
od;
grid:= function( t, data )
local tp, lt;
tp:= data.topmargin + 3;
lt:= data.leftmargin;
NCurses.Grid( t.dynamic.window, tp, tp + 10, lt, lt + 20,
tp + [ 0, 2 .. 10 ], lt + [ 0, 4 .. 20 ] );
end;
mode:= BrowseData.CreateMode( "knight", "", Concatenation( [
# standard actions
[ [ "E" ], BrowseData.actions.Error ],
[ [ "q", [ [ 27 ], "<Esc>" ] ], BrowseData.actions.QuitMode ],
[ [ "Q" ], BrowseData.actions.QuitTable ],
[ [ "?", [ [ NCurses.keys.F1 ], "<F1>" ] ],
BrowseData.actions.ShowHelp ],
[ [ [ [ NCurses.keys.F2 ], "<F2>" ] ],
BrowseData.actions.SaveWindow ] ],
# moves via sequences of arrow keys
actions ) );
# Construct and show the browse table.
steps:= 0;
NCurses.BrowseGeneric( rec(
work:= rec(
align:= "ct",
minyx:= [ 16, 21 ],
header:= [ "",
[ NCurses.attrs.UNDERLINE, true, "Changing Sides" ],
"" ],
main:= [],
m:= m,
n:= n,
mainFormatted:= matrix,
sepRow:= "-",
sepCol:= "|",
footer:= function( t )
if emp = [ 6, 6 ] and
ForAll( upperhalf, p -> matrix[ p[1] ][ p[2] ] = white ) then
return [ "", [ Concatenation( String( steps ), " steps " ),
NCurses.ColorAttr( "red", -1 ),
"(done)" ] ];
else
return [ "", Concatenation( String( steps ), " steps" ) ];
fi;
end,
availableModes:= [ mode ],
cacheEntries:= true,
SpecialGrid:= grid,
),
dynamic:= rec(
activeModes:= [ mode ],
),
) );
end );
#############################################################################
##
#V BrowseChangeSidesSolutions
##
BindGlobal( "BrowseChangeSidesSolutions", [
[259,259,260,258,258,260,259,261,261,258,258,261,258,260,260,259,259,261,
258,261,261,258,260,260,259,259,261,259,259,261,258,260,260,259,260,260,
258,258,261,259,261,261,258,258,260,259,259,260,258,258,260,259,261,261,
259,261,261,258,258,260,259,259,260,258,258,260,259,261,261,258,258,261,
259,260,260,258,260,260,259,259,261,259,259,261,258,260,260,258,261,261,
259,259,261,258,260,260,258,258,261,259,261,261,258,258,260,259,259,260],
[259,259,260,258,258,260,259,261,261,258,258,261,258,260,260,259,259,261,
258,261,261,258,260,260,259,259,261,259,259,261,258,260,260,259,260,260,
258,258,261,259,261,261,258,258,260,259,261,261,258,258,260,259,259,260,
259,261,261,258,258,260,259,259,260,258,258,260,259,261,261,258,258,261,
259,260,260,258,260,260,259,259,261,259,259,261,258,260,260,258,261,261,
259,259,261,258,258,261,258,260,260,259,259,260,258,258,260,261,261,259],
[259,261,261,258,258,260,259,259,260,258,260,260,258,258,261,259,259,261,
258,261,261,258,260,260,259,259,261,259,259,261,258,260,260,259,260,260,
258,258,261,259,261,261,258,258,260,259,261,261,258,258,260,259,259,260,
259,259,260,258,258,260,259,261,261,258,258,260,259,261,261,258,258,261,
259,260,260,258,260,260,259,259,261,259,259,261,258,260,260,258,261,261,
259,259,261,258,258,261,258,260,260,259,259,260,258,258,260,261,261,259],
] );
#############################################################################
##
#E
