can't start scala on windows 7

Question

I downloaded scala 2.8 but when executing scala.bat it says

system cannot find set_home

I didn't have this problem with old version of scala.

So how to launch scala ?

Update: I'm on windows 7, I have setup JAVA_HOME environment variable. the problem is the set_home batch command that is not known.

I have found the official tutorial here: http://www.scala-lang.org/node/310

I did exactly like they asked but IT DOESN'T WORK WITH SCALA 2.8 ON WINDOWS 7

It seems they didn't test !

This is their batch file (scala.bat), I don't see when scala is even started!:

if "%OS%"=="Windows_NT" (
  @setlocal
  call :set_home
  set _ARGS=%*
) else (
  set _SCALA_HOME=%SCALA_HOME%
  rem The following line tests SCALA_HOME instead of _SCALA_HOME, because
  rem the above change to _SCALA_HOME is not visible within this block.
  if "%SCALA_HOME%"=="" goto error1
  call :set_args
)

rem We use the value of the JAVACMD environment variable if defined
set _JAVACMD=%JAVACMD%

if "%_JAVACMD%"=="" (
  if not "%JAVA_HOME%"=="" (
    if exist "%JAVA_HOME%\bin\java.exe" set _JAVACMD=%JAVA_HOME%\bin\java.exe
  )
)

if "%_JAVACMD%"=="" set _JAVACMD=java

rem We use the value of the JAVA_OPTS environment variable if defined
set _JAVA_OPTS=%JAVA_OPTS%
if "%_JAVA_OPTS%"=="" set _JAVA_OPTS=-Xmx256M -Xms32M

set _TOOL_CLASSPATH=
if "%_TOOL_CLASSPATH%"=="" (
  for %%f in ("%_SCALA_HOME%\lib\*") do call :add_cpath "%%f"
  if "%OS%"=="Windows_NT" (
    for /d %%f in ("%_SCALA_HOME%\lib\*") do call :add_cpath "%%f"
  )
)

Answer 1

We did test it on Windows 7, and just to be sure I tested it again now and it works for me (Windows 7, 64 bit).

Can you please show the output of running the following commands:

C:\Users\luc\Desktop\scala-2.8.0.final>echo %PATH%
C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\Wind
owsPowerShell\v1.0\

C:\Users\luc\Desktop\scala-2.8.0.final>java -version
java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b06)
Java HotSpot(TM) 64-Bit Server VM (build 17.0-b16, mixed mode)

C:\Users\luc\Desktop\scala-2.8.0.final>bin\scala
Welcome to Scala version 2.8.0.final (Java HotSpot(TM) 64-Bit Server VM, Java 1.
6.0_21).
Type in expressions to have them evaluated.
Type :help for more information.

scala> 1+1
res0: Int = 2

Did you post the full batch script? If so, it's corrupted, it should contain more code below (and comments above). Try downloading again.

@echo off

rem ##########################################################################
rem # Copyright 2002-2010, LAMP/EPFL
rem #
rem # This is free software; see the distribution for copying conditions.
rem # There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
rem # PARTICULAR PURPOSE.
rem ##########################################################################

rem We adopt the following conventions:
rem - System/user environment variables start with a letter
rem - Local batch variables start with an underscore ('_')

if "%OS%"=="Windows_NT" (
  @setlocal
  call :set_home
  set _ARGS=%*
) else (
  set _SCALA_HOME=%SCALA_HOME%
  rem The following line tests SCALA_HOME instead of _SCALA_HOME, because
  rem the above change to _SCALA_HOME is not visible within this block.
  if "%SCALA_HOME%"=="" goto error1
  call :set_args
)

rem We use the value of the JAVACMD environment variable if defined
set _JAVACMD=%JAVACMD%

if "%_JAVACMD%"=="" (
  if not "%JAVA_HOME%"=="" (
    if exist "%JAVA_HOME%\bin\java.exe" set _JAVACMD=%JAVA_HOME%\bin\java.exe
  )
)

if "%_JAVACMD%"=="" set _JAVACMD=java

rem We use the value of the JAVA_OPTS environment variable if defined
set _JAVA_OPTS=%JAVA_OPTS%
if "%_JAVA_OPTS%"=="" set _JAVA_OPTS=-Xmx256M -Xms32M

set _TOOL_CLASSPATH=
if "%_TOOL_CLASSPATH%"=="" (
  for %%f in ("%_SCALA_HOME%\lib\*") do call :add_cpath "%%f"
  if "%OS%"=="Windows_NT" (
    for /d %%f in ("%_SCALA_HOME%\lib\*") do call :add_cpath "%%f"
  )
)

set _PROPS=-Dscala.home="%_SCALA_HOME%" -Denv.emacs="%EMACS%" 

rem echo "%_JAVACMD%" %_JAVA_OPTS% %_PROPS% -cp "%_TOOL_CLASSPATH%" scala.tools.nsc.MainGenericRunner  %_ARGS%
"%_JAVACMD%" %_JAVA_OPTS% %_PROPS% -cp "%_TOOL_CLASSPATH%" scala.tools.nsc.MainGenericRunner  %_ARGS%
goto end

rem ##########################################################################
rem # subroutines

:add_cpath
  if "%_TOOL_CLASSPATH%"=="" (
    set _TOOL_CLASSPATH=%~1
  ) else (
    set _TOOL_CLASSPATH=%_TOOL_CLASSPATH%;%~1
  )
goto :eof

rem Variable "%~dps0" works on WinXP SP2 or newer
rem (see http://support.microsoft.com/?kbid=833431)
rem set _SCALA_HOME=%~dps0..
:set_home
  set _BIN_DIR=
  for %%i in (%~sf0) do set _BIN_DIR=%_BIN_DIR%%%~dpsi
  set _SCALA_HOME=%_BIN_DIR%..
goto :eof

:set_args
  set _ARGS=
  :loop
  rem Argument %1 may contain quotes so we use parentheses here
  if (%1)==() goto :eof
  set _ARGS=%_ARGS% %1
  shift
  goto loop

rem ##########################################################################
rem # errors

:error1
echo ERROR: environment variable SCALA_HOME is undefined. It should point to your installation directory.
goto end

:end
if "%OS%"=="Windows_NT" @endlocal

Answer 2

You need to add the bin directory of your Scala installation to your PATH environment variable.

For example, if you installed Scala in C:\Dev\scala-2.8.0.final, then add C:\Dev\scala-2.8.0.final\bin to your PATH.

Look here for instructions on how to change PATH on Windows 7:

How to Add, Remove or Edit Environment variables in Windows 7?

Note: You have to close and re-open the command prompt after you set an environment variable; if you leave the command prompt open, it will not pick up the change.