PLAY THIS GAME?

@echo off
if "%~1" == "startGame" goto :game
if "%~1" == "startController" goto :controller


::------------------------------------------------------------
:: verify existence of CHOICE command
:: set up a macro appropriately depending on available version

set "choice="
2>nul >nul choice /c:yn /t 0 /d y
if errorlevel 1 if not errorlevel 2 set "choice=choice /cs"
if not defined choice (
 2>nul >nul choice /c:yn /t:y,1
 if errorlevel 1 if not errorlevel 2 set "choice=choice /s"
)
if not defined choice (
 echo ERROR: This game requires the CHOICE command, but it is missing.
 echo Game aborted.
 echo(
 echo A 16 bit port of CHOICE.EXE from FREEDOS is available at
 echo http://winsupport.org/utilities/freedos-choice.html
 echo(
 echo A 32 bit version from ??? suitable for 64 bit machines is available at
 echo http://hp.vector.co.jp/authors/VA007219/dkclonesup/choice.html
 echo(
 exit /b
)


::---------------------------------------------------------------------
:: setup some global variables used by both the game and the controller

set "keys=ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
set "keyFile=key.txt"
set "cmdFile=cmd.txt"


::------------------------------------------
:: launch the game and the controller

copy nul "%keyFile%" >nul
start "" /b "%~f0" startController 9^>^>%keyFile% 2^>nul ^>nul
cmd /c "%~f0" startGame 9^<%keyFile% ^<nul
echo(

::--------------------------------------------------------------------------------
:: Upon exit, wait for the controller to close before deleting the temp input file

:close
2>nul (>>"%keyFile%" call )||goto :close
del "%keyFile%"
exit /b


::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:game
setlocal disableDelayedExpansion
title %~nx0
cls

::----------------------------
:: user configurable options

set "up=W"
set "down=S"
set "left=A"
set "right=D"

set "width=40"   max=99
set "height=25"  max=99
:: max playing field: (width-2)*(height-2) <= 1365

::----------------------------
:: resize the console window

set /a cols=width+1, lines=height+10, area=(width-2)*(height-2)
if %area% gtr 1365 (
 echo ERROR: Playfield area too large
 >"%cmdFile%" (echo quit)
 exit
)
if %lines% lss 14 set lines=14
if %cols% lss 46 set cols=46
mode con: cols=%cols% lines=%lines%

::----------------------------
:: define variables

set "spinner1=-"
set "spinner2=\"
set "spinner3=|"
set "spinner4=/"
set "spinner= spinner1 spinner2 spinner3 spinner4 "

set "space= "
set "bound=#"
set "food=+"
set "head=@"
set "body=O"
set "death=X"
set "playerSpace=%space%%food%"

set "xDiff%up%=+0"
set "xDiff%down%=+0"
set "xDiff%left%=-1"
set "xDiff%right%=+1"

set "yDiff%up%=-1"
set "yDiff%down%=+1"
set "yDiff%left%=+0"
set "yDiff%right%=+0"

set "%up%Axis=Y"
set "%down%Axis=Y"
set "%left%Axis=X"
set "%right%Axis=X"

set "delay1=20"
set "delay2=15"
set "delay3=10"
set "delay4=7"
set "delay5=5"
set "delay6=3"
set "delay0=0"

set "desc1=Sluggard"
set "desc2=Crawl"
set "desc3=Slow"
set "desc4=Normal"
set "desc5=Fast"
set "desc6=Insane"
set "desc0=Unplayable"

set "spinnerDelay=3"

set /a "width-=1, height-=1"


::---------------------------
:: define macros

::define a Line Feed (newline) string (normally only used as !LF!)
set LF=^


::Above 2 blank lines are required - do not remove

::define a newline with line continuation
set ^"\n=^^^%LF%%LF%^%LF%%LF%^^"

:: setErr
:::  Sets the ERRORLEVEL to 1
set "setErr=(call)"

:: clrErr
:::  Sets the ERRORLEVEL to 0
set "clrErr=(call )"


:: getKey  ValidKeys
::: Check for keypress. Only accept keys listed in ValidKeys
::: Return result in Key variable. Key is undefined if no valid keypress.
set getKey=%\n%
for %%# in (1 2) do if %%#==2 (for /f "eol= delims= " %%1 in ("!args!") do (%\n%
 set "validKeys=%%1"%\n%
 set "key="%\n%
 ^<^&9 set /p "key="%\n%
 if defined key if "!key!" neq ":" (%\n%
   set /a key-=1%\n%
   for %%K in (!key!) do set "key=!keys:~%%K,1!"%\n%
 )%\n%
 for %%K in (!key!) do if "!validKeys:%%K=!" equ "!validKeys!" set "key="%\n%
)) else set args=


:: draw
:::  draws the board
set draw=%\n%
cls%\n%
for /l %%Y in (0,1,%height%) do echo(!line%%Y!%\n%
echo Speed=!Difficulty!%\n%
echo Score=!score!


:: test  X  Y  ValueListVar
:::  tests if value at coordinates X,Y is within contents of ValueListVar
set test=%\n%
for %%# in (1 2) do if %%#==2 (for /f "tokens=1-3" %%1 in ("!args!") do (%\n%
 for %%A in ("!line%%2:~%%1,1!") do if "!%%3:%%~A=!" neq "!%%3!" %clrErr% else %setErr%%\n%
)) else set args=


:: plot  X  Y  ValueVar
:::  places contents of ValueVar at coordinates X,Y
set plot=%\n%
for %%# in (1 2) do if %%#==2 (for /f "tokens=1-3" %%1 in ("!args!") do (%\n%
 set "part2=!line%%2:~%%1!"%\n%
 set "line%%2=!line%%2:~0,%%1!!%%3!!part2:~1!"%\n%
)) else set args=


::--------------------------------------
:: start the game
setlocal enableDelayedExpansion
call :initialize


::--------------------------------------
:: main loop (infinite loop)
for /l %%. in (1 0 1) do (

 %=== compute time since last move ===%
 for /f "tokens=1-4 delims=:.," %%a in ("!time: =0!") do set /a "t2=(((1%%a*60)+1%%b)*60+1%%c)*100+1%%d-36610100, tDiff=t2-t1"
 if !tDiff! lss 0 set /a tDiff+=24*60*60*100

 if !tDiff! geq !delay! (
   %=== delay has expired, so time for movement ===%

   %=== establish direction ===%
   %getKey% ASDW
   for %%K in (!key!) do if "!%%KAxis!" neq "!axis!" (
     set /a "xDiff=xDiff%%K, yDiff=yDiff%%K"
     set "axis=!%%KAxis!"
   )

   %=== erase the tail ===%
   set "TX=!snakeX:~-2!"
   set "TY=!snakeY:~-2!"
   set "snakeX=!snakeX:~0,-2!"
   set "snakeY=!snakeY:~0,-2!"
   %plot% !TX! !TY! space

   %=== compute new head location and attempt to move ===%
   set /a "X=PX+xDiff, Y=PY+yDiff"
   set "X= !X!"
   set "Y= !Y!"
   set "X=!X:~-2!"
   set "Y=!Y:~-2!"
   (%test% !X! !Y! playerSpace) && (

     %=== move successful ===%

     %=== remove the new head location from the empty list ===%
     for %%X in ("!X!") do for %%Y in ("!Y!") do set "empty=!empty:#%%~X %%~Y=!"

     (%test% !X! !Y! food) && (
       %=== moving to food - eat it ===%

       %=== restore the tail ===%
       %plot% !TX! !TY! body
       set "snakeX=!snakeX!!TX!"
       set "snakeY=!snakeY!!TY!"

       %=== increment score and locate and draw new food ===%
       set /a "score+=1, F=(!random!%%(emptyCnt-=1))*6+1"
       for %%F in (!F!) do (%plot% !empty:~%%F,5! food)

     ) || (
       %=== moving to empty space ===%

       %=== add the former tail position to the empty list ===%
       set "empty=!empty!#!TX! !TY!"
     )

     %=== draw the new head ===%
     if defined snakeX (%plot% !PX! !PY! body)
     %plot% !X! !Y! head

     %=== Add the new head position to the snake strings ===%
     set "snakeX=!X!!snakeX!"
     set "snakeY=!Y!!snakeY!"
     set "PX=!X!"
     set "PY=!Y!"

     %draw%

   ) || (

     %=== failed move - game over ===%
     %plot% !TX! !TY! body
     call :spinner !PX! !PY! death
     %draw%
     echo(
     call :ask "Would you like to play again? (Y/N)" YN
     if /i "!key!" equ "N" (
       >"%cmdFile%" (echo quit)
       exit
     ) else (
       call :initialize
     )
   )

   set /a t1=t2
 )
)

:ask  Prompt  ValidKeys
:: Prompt for a keypress. ValidKeys is a list of acceptable keys
:: Wait until a valid key is pressed and return result in Key variable
>"%cmdFile%" (echo prompt)
<nul set /p "=%~1 "
:purge
(%getKey%
if not defined key goto :purge
:getResponse
(%getKey% %2)
if not defined key (
 >"%cmdFile%" (echo one)
 goto :getResponse
)
exit /b


:spinner  X  Y  ValueVar
set /a d1=-1000000
for /l %%N in (1 1 5) do for %%C in (%spinner%) do (
 call :spinnerDelay
 %plot% %1 %2 %%C
 %draw%
)
call :spinnerDelay
(%plot% %1 %2 %3)
exit /b

:spinnerDelay
for /f "tokens=1-4 delims=:.," %%a in ("!time: =0!") do set /a "d2=(((1%%a*60)+1%%b)*60+1%%c)*100+1%%d-36610100, dDiff=d2-d1"
if %dDiff% lss 0 set /a dDiff+=24*60*60*100
if %dDiff% lss %spinnerDelay% goto :spinnerDelay
set /a d1=d2
exit /b


::-------------------------------------
:initialize
cls

echo Speed Options:
echo                       delay
echo    #   Description  (seconds)
echo   ---  -----------  ---------
echo    1   Sluggard        0.20
echo    2   Crawl           0.15
echo    3   Slow            0.10
echo    4   Normal          0.07
echo    5   Fast            0.05
echo    6   Dylan's Noob          0.03
echo    0   GRAND BOSS DYLAN     none
echo(
call :ask "Pick a speed (1-6, 0):" 1234560
set "difficulty=!desc%key%!"
set "delay=!delay%key%!"
echo %key% - %difficulty%
echo(
<nul set /p "=Initializing."
set "axis=X"
set "xDiff=+1"
set "yDiff=+0"
set "empty="
set /a "PX=1, PY=height/2, FX=width/2+1, FY=PY, score=0, emptyCnt=0, t1=-1000000"
set "snakeX= %PX%"
set "snakeY= %PY%"
set "snakeX=%snakeX:~-2%"
set "snakeY=%snakeY:~-2%"
for /l %%Y in (0 1 %height%) do (
 <nul set /p "=."
 set "line%%Y="
 for /l %%X in (0,1,%width%) do (
   set "cell="
   if %%Y equ 0        set "cell=%bound%"
   if %%Y equ %height% set "cell=%bound%"
   if %%X equ 0        set "cell=%bound%"
   if %%X equ %width%  set "cell=%bound%"
   if %%X equ %PX% if %%Y equ %PY% set "cell=%head%"
   if not defined cell (
     set "cell=%space%"
     set "eX= %%X"
     set "eY= %%Y"
     set "empty=!empty!#!eX:~-2! !eY:~-2!"
     set /a emptyCnt+=1
   )
   if %%X equ %FX% if %%Y equ %FY% set "cell=%food%"
   set "line%%Y=!line%%Y!!cell!"
 )
)
(%draw%)
echo(
echo Movement keys: %up%=up %down%=down %left%=left %right%=right
echo Avoid running into yourself (%body%%body%%head%) or wall (%bound%)
echo Eat food (%food%) to grow.
echo(
call :ask "Press any alpha-numeric key to start..." %keys%
>"%cmdFile%" (echo go)
exit /b


::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:controller

setlocal enableDelayedExpansion
set "cmd=hold"
set "key="
for /l %%. in (1 0 1) do (
 if "!cmd!" neq "hold" (
   %choice% /n /c:!keys!
   set "key=!errorlevel!"
 )
 if exist "%cmdFile%" (
   <"%cmdFile%" set /p "cmd="
   del "%cmdFile%"
 )
 if "!cmd!" equ "quit" exit
 if defined key (
   if "!cmd!" equ "prompt" >&9 (echo
   >&9 (echo !key!)
   if "!cmd!" neq "go" set "cmd=hold"
   set "key="
 )
)

Fair use. No copyright intended.