Tutorial Project. Release 2

Written by Victor Yukhtenko. Email: victor@pdc.spb.su

The programs listed below are part of the Evolutions Tutorial Project article.

Game Rules ...

Goal

Demonstrating the properties of Visual Prolog language and simple programming techniques, including:

• The generating of random numbers;
• The Class Interface;
• The use of the same interface in different classes;
• The use of facts-variables;
• The generating a simple exceptions;
• The simple exception handling;
• The use of constants.

Functionality

• If the machine makes the first move, it makes it randomly;
• If model has no obvious secure move, then it makes it randomly.

Code

• Tested with Visual Prolog 7.3 build 7302.

Compare to Tutorial Project. Release 1:

• • Models of behavior of a human and of a computer built as dynamic classes;
  • Predicates explicitly related to the user interface placed to a separate class;
• In this version used field size 6x6 pixels.;
• Due to an inefficient algorithm for the computer game field size more than 36 cells (6x6, for example) to install not recommended.

Install

To get the full set of projects of the series of the Polyline projects, please download archives using links at PDC forum:

• VipSpbSDK_PE_73_Examples_Polyline_1_14.zip
• VipSpbSDK_PE_73_Tools_Polyline_1_14.zip]

to any convenient directory. The directory named VipSpbSDK will be created automatically.

If you have the VipSpbSDK installed, then please open project Examples\Polyline\Polyline2\Polyline2.prj.

If you do not have the full set of examples from the VipSpbSDK, then please do as follows:

• Create the new project using the interface strategy console
• Build the project
• Replace the content of the file "main.pro" by the code proposed below.
• Build the project again. While building the project please respond “Add All”, when there will be the proposal to include additional packages to the project.

Run

Run the application using the “E” of the IDE or run the executable at the directory EXE.

/*********************************************************
SpbSolutions/Examples/Polyline
 
Predicates, which represent the strategy
  resolveMove,
  moveCandidate,
  successfulMove,
  rule_nd,
based on solutions proposed by Elena Efimova
*********************************************************/
goal
    mainExe::run(main::run).
 
implement main
open core
 
constants
    className = "PolyLine".
    classVersion = "1.0".
 
clauses
    classInfo(className, classVersion).
 
clauses
    run():-
        console::init(),
        game::run().
end implement main
 
/**************************************
The Game class manages the playing process
**************************************/
class game
    open core
 
predicates
    classInfo : core::classInfo.
 
constants
    maxRow_C:positive=6.
    maxColumn_C:positive=6.
 
domains
    cell = c(positive,positive).
    moveType_D=
        ordinary_S;
        winner_S.
 
properties
    polyline_P:cell*.
 
predicates
    run:().
    set:(string CellAsString).
    rule_nd: (cell,cell) nondeterm (i,o) (i,i).
    ruleLimited_nd:(cell,cell)->cell nondeterm.
 
end class game
 
implement game
open core
 
constants
    className = "Game".
    classVersion = "1.0".
 
clauses
    classInfo(className, classVersion).
 
class facts
    human_V:player:=erroneous.
    computer_V:player:=erroneous.
    polyline_P:cell*:=[].
    endOfGame_V:boolean:=false.
 
clauses
    run():-
        human_V:=human::new(),
        computer_V:=computer::new(),
        playerTurn().
 
class predicates
    playerTurn:().
clauses
    playerTurn():-
        PlayerTurnStr=humanInterface::getInput(humanInterface::playerTurn_S),
        not(PlayerTurnStr=""),
        try
            hasDomain(positive,PlayerTurn),
            PlayerTurn=toTerm(PlayerTurnStr),
            if PlayerTurn=2 then
                Player=human_V,
                StarterName="Computer" % because of it is used NextPlayer in the Play predicate
            else
                Player=computer_V,
                StarterName="Human"
            end if,
            humanInterface::showStage(),
            !,
            humanInterface::announceStarter(StarterName),
            play(Player)
        catch _TraceID1 do
            humanInterface::announceChoiceError(humanInterface::errorMustBeNumber_S)
        end try,
            !,
            polyline_P:=[],
            endOfGame_V:=false,
            playerTurn().
    playerTurn().
 
class predicates
    play:(player Player).
clauses
    play(Player):-
        endOfGame_V=true,
        !,
        if Player=human_V then
            humanInterface::announceWin("Human")
        else
            humanInterface::announceWin("Computer")
        end if.
    play(Player):-
        if Player=human_V then
            NextPlayer=computer_V,
            Name="Computer"
        else
            NextPlayer=human_V,
            Name="Human"
        end if,
        !,
        humanInterface::announceMovingPlayer(Name),
        NextPlayer:move(),
        play(NextPlayer).
 
clauses
    set(InputString):-
        Cell=toTerm(InputString),
        handleInput (Cell).
 
class predicates
    handleInput:(cell Cell).
clauses
    handleInput(Cell):-
        list::isMember(Cell,polyline_P),
        try
            _=makePolyLine(Cell,polyline_P)   % If the Cell is not acceptable,
                                                            % then exception appears and we ignore it
                                                            % using fail
        catch _TraceID do
            fail
        end try,
        !,
        endOfGame_V:=true,
        humanInterface::showMove(Cell,winner_S).
    handleInput (Cell):-
        polyline_P:=makePolyLine(Cell,polyline_P),
        !,
        humanInterface::showMove(Cell,ordinary_S).
 
class predicates
    makePolyLine: (cell,cell*)-> cell* multi.
clauses
    makePolyLine(c(X,Y),[])=[c(X,Y)]:-
        X>0,X<=maxColumn_C,
        Y>0,Y<=maxRow_C,
        !.
    makePolyLine(NewCell,[SingleCell])=[NewCell,SingleCell]:-
        game::rule_nd(SingleCell, NewCell),
        !.
    makePolyLine(NewCell,[Left, RestrictingCell | PolyLineTail])=[NewCell, Left, RestrictingCell | PolyLineTail]:-
        NewCell=ruleLimited_nd(Left,RestrictingCell).
    makePolyLine(NewCell,PolyLine)=list::reverse([NewCell,Left, RestrictingCell | PolyLineTail]):-
        [Left, RestrictingCell | PolyLineTail]= list::reverse(PolyLine),
        NewCell=ruleLimited_nd(Left,RestrictingCell).
    makePolyLine(NewCell,_PolyLine)= _PolyLine1:-
        exception::raise(classInfo,wrongMoveException,[namedValue("data",string(toString(NewCell)))]).
 
class predicates
    wrongMoveException:exception.
clauses
    wrongMoveException
        (
        classInfo,
        predicate_Name(),
        "The point % can not prolong the polyline!"
        ).
 
clauses
    ruleLimited_nd(Cell,RestrictingCell)=NewCell:-
        rule_nd(Cell,NewCell),
            not(NewCell = RestrictingCell).
 
clauses
    rule_nd(c(X, Y), c(X + 1, Y)):- X < maxColumn_C.
    rule_nd(c(X, Y), c(X, Y + 1)):- Y < maxrow_C.
    rule_nd(c(X, Y), c(X - 1, Y)):- X > 1.
    rule_nd(c(X, Y), c(X, Y - 1)):- Y > 1.
 
end implement game
 
/******************************************
  Interface Player
  Player in responce to predicate call move()
  must  reply by calling set(ResponceMove)
******************************************/
interface player
 
predicates
    move:().
end interface player
 
/********************************
  The Class Human
********************************/
class human:player
open core
 
end class human
 
implement human
open core, exception
 
clauses
    move():-
        InputString=humanInterface::getInput(humanInterface::playerMove_S),
        try
            game::set(InputString)
        catch TraceID do
            handleException(TraceID),
            fail
        end try,
        !.
    move():-
        move().
 
class predicates
    handleException:(exception::traceId TraceID).
clauses
    handleException(TraceID):-
        foreach Descriptor=exception::getDescriptor_nd(TraceID) do
            Descriptor = exception::descriptor(
                _ClassInfo1,
                exception::exceptionDescriptor(_ClassInfo2,_PredicateName,Description),
                _Kind,
                ExtraInfo,
                _GMTTime,
                _ExceptionDescription,
                _ThreadId),
            if
                ExtraInfo=[namedValue("data",string(CellPointer))]
            then
                ErrorMsg=string::format(Description,CellPointer),
                humanInterface::announceError(ErrorMsg)
            else
                humanInterface::announceError("")
            end if
        end foreach.
 
end implement human
 
/******************************************
  Class Сomputer
******************************************/
class computer:player
predicates
    classInfo : core::classInfo.
end class computer
 
implement computer
open core
 
constants
    className = "Computer".
    classVersion = "1.0".
 
clauses
    classInfo(className, classVersion).
 
clauses
    move():-
        Cell=resolveMove(),
        game::set(toString(Cell)).
 
predicates
    resolveMove:()->game::cell.
clauses
    resolveMove()=Cell:-
        Cell=successfulMove(game::polyline_P),
        !.
    resolveMove()=Cell:-
        moveCandidate(game::polyline_P,_PolyLine,Cell),
        !.
    resolveMove()=game::c(X+1,Y+1):-
        X=math::random(game::maxColumn_C-1),
        Y=math::random(game::maxRow_C-1).
 
class predicates
    successfulMove: (game::cell*)->game::cell nondeterm.
clauses
    successfulMove(PolyLine)=Cell:-
        moveCandidate(PolyLine,_PolyLine1,Cell),
            list::isMember(Cell, PolyLine),
            !.
    successfulMove(PolyLine)=Cell:-
        moveCandidate(PolyLine, PolyLine1, Cell),
            not(_=successfulMove(PolyLine1)).
 
class predicates
    moveCandidate: (game::cell*,game::cell* [out],game::cell [out]) nondeterm.
clauses
    moveCandidate([Cell],[Cell,NewCell], NewCell):-
        game::rule_nd(Cell, NewCell),
        !.
    moveCandidate([Left, RestrictingCell | PolyLine],[NewCell,Left, RestrictingCell| PolyLine], NewCell):-
        NewCell=game::ruleLimited_nd(Left,RestrictingCell).
    moveCandidate(PolyLine,list::reverse([NewCell,Left, RestrictingCell |PolyLineTail]),NewCell):-
        [Left, RestrictingCell |PolyLineTail] = list::reverse(PolyLine),
        NewCell=game::ruleLimited_nd(Left,RestrictingCell).
 
end implement computer
 
/******************************************
  Class HumanInterface supports the communication
  of the human with the computer
******************************************/
class humanInterface
open core
 
predicates
    showStage:().
    showMove:(game::cell,game::moveType_D).
    getInput:(inputType_D)->string InputString.
 
domains
    inputType_D=
        playerMove_S;
        playerTurn_S.
 
predicates
    announceStarter:(string Name).
    announceMovingPlayer:(string Name).
    announceWin:(string Name).
    announceError:(string Description).
    announceError:().
 
domains
    choiceError_D=
        errorMustBeNumber_S;
        errorPlayerTurn_S.
predicates
    announceChoiceError:(choiceError_D).
 
end class humanInterface
 
implement humanInterface
open core
 
constants
    cellMarkedOrdinary_C="*".
    cellMarkedWinner_C="O".
 
constants % messages
    movingPlayer_C="% is thinking".
    beginner_C="First move done by: %".
    error_C="Error, % ".
    congratulation_C="Player % has won!".
 
    playerMove_C="Enter the move as  c(X,Y): ".
    playerTurn_C="\nWho is moving first (1-human, 2-computer, Enter-exit)?:".
 
    errorMustBeNumber_C="\nIt must be numeric! Please repeat the input:".
    errorPlayerTurn_C="\nNo player with this ID! Please repeat the input:".
 
constants
    verticalSpace_C=2.
    horizontalSpace_C=3.
    emptyLineLenght_C=80.
 
constants % Position of Line
    starterLine_C=1.
    announceLine_C=starterLine_C+1.
    actionLine_C=announceLine_C+1.
    polylineLine_C=actionLine_C+1.
 
clauses
    getInput(InputType)=Input:-
        inputInvitation(InputType),
        Input = console::readLine(),
        console::clearInput().
 
class predicates
    inputInvitation:(inputType_D).
clauses
    inputInvitation(playermove_S):-
        clearMessageArea(actionLine_C),
        writeMessage(actionLine_C,"%",playermove_C).
    inputInvitation(playerTurn_S):-
        console::clearOutput(),
        console::write(playerTurn_C).
 
clauses
    showStage():-
        console::clearOutput(),
        foreach I = std::fromTo(1, game::maxColumn_C) do
            console::setLocation(console_native::coord(horizontalSpace_C*I, 0)),
            console::write(I)
        end foreach,
        foreach J = std::fromTo(1, game::maxRow_C) do
            console::setLocation(console_native::coord(0, verticalSpace_C*J)),
            console::write(J)
        end foreach.
 
clauses
    showMove(game::c(X,Y),_Type):-
        console::setLocation(console_native::coord(horizontalSpace_C*X, verticalSpace_C*Y)),
        fail.
    showMove(_Cell,game::ordinary_S):-
        console::write(cellMarkedOrdinary_C).
    showMove(_Cell,game::winner_S):-
        console::write(cellMarkedWinner_C).
 
clauses
    announceStarter(Name):-
        clearMessageArea(starterLine_C),
        writeMessage(starterLine_C,beginner_C,Name).
 
clauses
    announceChoiceError(errorMustBeNumber_S):-
        console::write(errorMustBeNumber_C),
        _ = console::readLine().
    announceChoiceError(errorPlayerTurn_S):-
        console::write(errorPlayerTurn_C),
        _ = console::readLine().
 
clauses
    announceError():-
        announceError("").
 
    announceError(ErrorText):-
        clearMessageArea(announceLine_C),
        writeMessage(announceLine_C,error_C,ErrorText).
 
clauses
    announceWin(Name):-
        clearMessageArea(announceLine_C),
        writeMessage(announceLine_C,congratulation_C,Name),
        showPolyLine(),
        _ = console::readLine().
 
clauses
    announceMovingPlayer(Name):-
        clearMessageArea(announceLine_C),
        clearMessageArea(actionLine_C),
        writeMessage(actionLine_C,movingPlayer_C,Name).
 
class predicates
    showPolyLine:().
clauses
    showPolyLine():-
        clearMessageArea(actionLine_C),
        writeMessage(polylineLine_C,"%",toString(game::polyline_P)).
 
class predicates
    clearMessageArea:(positive AreaID).
clauses
    clearMessageArea(AreaID):-
        console::setLocation(console_native::coord(0,game::maxRow_C*verticalSpace_C+AreaID)),
        console::write(string::create(emptyLineLenght_C," ")).
 
class predicates
    writeMessage:(positive AreaID,string FormatString,string ParameterString).
clauses
    writeMessage(AreaID,FormatString,ParameterString):-
        console::setLocation(console_native::coord(0, game::maxRow_C*verticalSpace_C+AreaID)),
        console::writef(FormatString,ParameterString).
 
end implement humanInterface