此批处理中不期望goto

Question

@echo off
:start
set string=
set lo=1
set a=0
set b=0
set cl=1
set cloop=
set google=0
set k=0
set r=0
set id=
set t=0
set f=0

set /p string=? 
if defined string (
echo %string%
goto loop
) else (
echo please enter a string
goto start
)
:loop
set a=
for /f "tokens=%lo%" %%G IN ("%string%") DO echo %%G 
if defined a (
echo %a%
set google=0
set /p cloop=<greetings.txt
pause
:cloop
set b=
for /f "tokens=%cl%" %%g IN ("%cloop%") DO set b=%%g
if defined string (
if %a%==%b% goto greetings
set /a cl=%cl%+1
goto cloop
) else (
set cl=0
set /a lo=%lo%+1
goto loop
)
) else (
goto google
)
:greetings
set f=0
set k=0
set r=0
set /p id=<greetingtone.dat
for /f "tokens=%cl%" %%g IN ("%id%") DO set t=%%g
start greeting.bat
call greeting.bat
goto talk
:google
echo not done yet
pause
goto start

i have narrowed it down to this line if %a%==%b% goto greetings when i remove it it runs
i have looked but i have no idea why it does not work please help the greetings.txt has "hi hello grunt" i think it might be the variables

Answer 1

If %a% or %b% are empty values, it is likely the compare is incomplete, and it is saying that the goto is not expected yet. For instance, if you type the following at a C:\\ prompt:

c:\>if a== echo ok

c:\>if ==a echo ok
echo was unexpected at this time.

c:\>if == echo ok
ok was unexpected at this time.

c:\>

If you enclose each value in quotes, then the comparison will still work even if one or both of the values are empty. For instance:

if "%a%"=="%b%" goto greetings

Answer 2

The normal reason for that an unexpected word in an IF statement is that IF has a very specific syntax, IF item1 operator item2 actionstatement(s) .

What is likely to be happening is that item1 AND item2 appear to be missing, so IF resolves that as IF == goto greetings . Since goto is not one of its known operators ( == , equ , neq , leq , lss , geq , gtr`) then it complains.

The question from here is - why do %a% and %b% appear to be empty?

Within a block statement (a parenthesised series of statements) , the entire block is parsed and then executed. Any %var% within the block will be replaced by that variable's value at the time the block is parsed - before the block is executed.

Hence, IF (something) else (somethingelse) will be executed using the values of %variables% at the time the IF is encountered. In your case, that means the outermost IF - in if defined string .

Two common ways to overcome this are 1) to use setlocal enabledelayedexpansion and use !var! in place of %var% to access the changed value of var or 2) to call a subroutine to perform further processing using the changed values.

Next problem is using a label within a block. Not a good idea. On some versions, a label will terminate the block. Call a subroutine instead.

 call :cloop

...
goto start
:cloop
 (whatever needs to be done)
goto :eof

(note that :cloop and :EOF have a required colon. on cloop it means "this is an internal subroutine - it's in the cuurrent batchfile." :EOF is a predefined label understood by CMD to mean end of file .)