Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!apple!voder!pyramid!prls!philabs!micomvax!ray
From: ray@micomvax.UUCP (Ray Dunn)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Interactive BAT files: here's how
Summary: A real solution
Message-ID: <1341@micomvax.UUCP>
Date: 25 Oct 88 22:03:36 GMT
References: <8810040015.AA21729@decwrl.dec.com>
Reply-To: ray@micomvax.UUCP (Ray Dunn)
Organization: Philips Electronics Ltd. (TDS - Montreal) St. Laurent QC, Canada
Lines: 61

I recently gave myself a red face by pontificating on how you should use
putenv to set interactively given values to environment variables from
inside a 'C' program.  It was correctly pointed out that this only affects a
*copy* of the variables.

I promised a solution, so... after putting up real money within my group as
a challenge, Eric Anderson (anderson@micomvax) who otherwise is usually very
usefully employed, came up with the following solution (:-).

He is the proud winner of exactly $2.10 (dont ask).

The batch file (any suitable name):

    if "%1"=="runbatch" goto runbatch
    getinput
    setinput %0
    rem   The name of this file (%0) is passed to setinp so can be re-executed
    rem   Control does not return here from the batchfile setinput
    :runbatch
    rem   Here you put the "real" commands you want the batch file to run
    rem   including the use of the environment variables defined in the
    rem   getinput/setinput mechanism


The 'C' program, getinp.exe, interacts with the user and generates the file
setinput.bat, which should be in the form:

    set var1=required value
    set var2=required value
    etc
    %1 runbatch

The set statements should reflect the user's responses as required.  The
last line calls the first batch file again, with parameter runbatch.

The code of getinp is very application specific, is simple, and is left as
an exercise for the reader.

The mechanism should be self-evident, and has the effect of running the batch
commands at the :runbatch label after the environment variables are
interactively defined.

With this basic mechanism understood, many variations and expansions can be
envisaged, one of which could be passing a question-string and a response
environment variable name to getinput etc.  Excrutiating contortions
involving multiple calls of getinput with different "runbatch" labels are
possible!

All donations to reimburse the $2.10 gladly accepted!

The mechanism shall be known as the Anderson Kludge.

Now the only question is, does Eric deserve promotion or should he be
condemned to eternally generating increasingly more and more obscure MS-DOS
batch files!!!

-- 
Ray Dunn.                      |   UUCP: ..!philabs!micomvax!ray
Philips Electronics Ltd.       |   TEL : (514) 744-8200   Ext: 2347
600 Dr Frederik Philips Blvd   |   FAX : (514) 744-6455
St Laurent. Quebec.  H4M 2S9   |   TLX : 05-824090