Win10 Batch script: \Notepad++ was unexpected at this time - windows

Question

This batch file gives the error in the title:
if "%PROCESSOR_ARCHITECTURE%"=="x86" (
echo FOOBAR
) else (
set HOME_EDIT=%SystemDrive%\Program Files (x86)\Notepad++
)
This is on a Win10 Pro x64 system (so the test is false).
Strangely the "set HOME_EDIT..." line, if executed by itself, does NOT generate the error. And this batch file seemed to work OK a few weeks ago (oldest complaint in the book, I know, but maybe the recent Win10 Creator's Update chagned something?).
Here's the whole output:
U:\Users\Dave\data\PC setup\2017-03 PC Setup for Win10>test.bat
\Notepad++ was unexpected at this time.
U:\Users\Dave\data\PC setup\2017-03 PC Setup for Win10> set HOME_EDIT=C:\Program Files (x86)\Notepad++
U:\Users\Dave\data\PC setup\2017-03 PC Setup for Win10>

Answer 1

Putting quotes around the assignment certainly solves the problem, but it has nothing to do with spaces. The problem is the ) in the path is closing the ELSE block prematurely unless the path is quoted (or escaped).
Without quotes, the ELSE block becomes
) else (
set HOME_EDIT=%SystemDrive%\Program Files (x86
)
And then the \Notepad++ is indeed unexpected, causing a syntax error.
I see 3 ways to eliminate the syntax error:
1) Eliminate the parentheses and put the SET command on the same line as ELSE
else set HOME_EDIT=%SystemDrive%\Program Files (x86)\Notepad++
2) Put quotes around the assignment
) else (
set "HOME_EDIT=%SystemDrive%\Program Files (x86)\Notepad++"
)
3) Escape the closing parenthesis
) else (
set HOME_EDIT=%SystemDrive%\Program Files (x86^)\Notepad++
)
If I were to do the assignment, I would use the predefined environment variable for the folder.
) else (
set "HOME_EDIT=%ProgramFiles(x86)%\Notepad++"
)

Answer 2

Answering my own question:
#drescherjm was correct (in the comments) that the immediate problem was lack of quote marks ("foo") around the argument to SET. Somehow this matters when the SET is within a IF statement, even tho it doesn't otherwise.
But adding quotes just broke something else later in my batch script:
set NEW_PATH=%HOME_WINDOWS%
set NEW_PATH=%NEW_PATH%;%BinPath%
set NEW_PATH=%NEW_PATH%;%BinPath%\ffmpeg\bin
set NEW_PATH=%NEW_PATH%;%BinPath%\mplayer
set NEW_PATH=%NEW_PATH%;%BinPath%\gui
set NEW_PATH=%NEW_PATH%;%BinPath%\dll
set NEW_PATH=%NEW_PATH%;%HOME_CYGWIN%\bin
set NEW_PATH=%NEW_PATH%;%HOME_CYGWIN%\sbin
set NEW_PATH=%NEW_PATH%;%HOME_CYGWIN%\usr\bin
set NEW_PATH=%NEW_PATH%;%HOME_CYGWIN%\usr\sbin
set NEW_PATH=%NEW_PATH%;%HOME_7ZIP%
set NEW_PATH=%NEW_PATH%;%HOME_EDIT%
set NEW_PATH=%NEW_PATH%;%HOME_DIFF%
set Path=%NEW_PATH%
setx Path "%NEW_PATH%"
If HOME_EDIT has quote marks in it, this causes SETX to fail.
Here's the fix I came up with (note lines marked with "TRICK1"):
REM The following is a trick to get around spaces in the path (TRICK1)
set HOME_EDIT=%SystemDrive%\%ProgramFiles(x86)%\Notepad++
if "%PROCESSOR_ARCHITECTURE%"=="x86" (
set HOME_CYGWIN=%SystemDrive%\cygwin
set HOME_EDIT=%SystemDrive%\Program Files\Notepad++
) else (
set HOME_CYGWIN=%SystemDrive%\cygwin64
REM (TRICK1 rem this out) set HOME_EDIT=%SystemDrive%\%ProgramFiles(x86)%\Notepad++
)
The path with the spaces in it is SET as a default value prior to entering the IF statement. This way no quote marks are needed, and SETX doesn't break later.