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From: userAKDU@mts.ucs.UAlberta.CA (Al Dunbar)
Newsgroups: comp.os.msdos.misc
Subject: Re: Getting rid of "syntax error" from .bat files - how to?
Message-ID: <2002@mts.ucs.UAlberta.CA>
Date: 11 Dec 90 05:44:20 GMT
References: <9467@pasteur.Berkeley.EDU> <5649@uafhp.uark.edu> <635@sun4dts.dts.ine.philips.nl>
Organization: MTS Univ of Alberta
Lines: 56

In article <635@sun4dts.dts.ine.philips.nl>, derek@sun4dts.dts.ine.philips.nl (derek) writes:
>sab@engr.uark.edu (Steven A. Breuer) writes:
>
>>In article <9467@pasteur.Berkeley.EDU>, brand@cad.Berkeley.EDU (Graham Brand) writes:
>>> I have written a batch file which accepts parameters from the command
>>> line using the:
>>>      if %1==param1
>>> syntax. It works fine except that if I don't pass any parameters, I
>>> get the above syntax error message. Is there any way to suppress this?
<<<deletions>>>
>
>You can also use the following trick that I often use:
>
>        if "%1"=="" goto NOPARMS
>
>        goto %1
>
>        rem here handle incorrect parameters.
>
>The "goto %1" branches to the label passed as parameter 1. This is especially
>useful in a batch file calling itself. (Think about it!)
>
 
Still redundant. Try:
 
goto _%1
rem handle incorrect parameters
 
:_
rem process the NOPARMS case here
 
:_asm
rem process an argument of 'asm', 'Asm', 'ASM' or etc.
 
Using a variable as a label makes argument processing case
insensitive, in addition to reducing the number of IF clauses
used. In addition, prefixing label names with '_' adds two more
benefits: 1) no need to handle the NOPARMS case separately, 2)
makes it possible to go only to those labels designated for this
purpose.
 
I always get an error when no label is found to match the
parameter, aborting the batch file before it can handle
the incorrect parameters. This is acceptable if these label
parameters are generated by the batch file itself, but if
used to process (random) input from users you want to
protect from this kind of thing, try:
 
if exist "argcheck"_%1 goto _%1
echo invalid argument: "%1"
 
-------------------+-------------------------------------------
Al Dunbar          |
Edmonton, Alberta  |  "this mind left intentionally blank"
CANADA             |          - Manuel Writer
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