MC Version Testing

[Peter Reid]

Title: MC Version Testing

Hi

I don't know if this will be of any help to anyone, but I find it helps me when running stacks upgraded to use features from new versions of MetaCard. In order to avoid problems whilst running a stack I always include a call to a handler to check that the current MetaCard engine is late enough to support necessary features.  Typically I call:

        if MCearlierThan("2.3.1",true) then quit

With the following handler to test the current MC version including beta and gamma releases:

function MCearlierThan minVersion, showMsg

  set the itemDelimiter to "."

  put the version into currVers

  put item 1 of currVers into mcVers

  put toLower(item 2 to -1 of currVers) into theVers

  repeat with i = number of chars in theVers down to 1

    put offset(char i of theVers, ".abcdefghijklmnopqrstuvwxyz") into posn

    if posn <> 0 then delete char i of theVers

  end repeat

  put (mcVers & "." & theVers) + 0 into mcVers

  put item 1 of minVersion into minMCvers

  put toLower(item 2 to -1 of minVersion) into theVers

  repeat with i = number of chars in theVers down to 1

    put offset(char i of theVers, ".abcdefghijklmnopqrstuvwxyz") into posn

    if posn <> 0 then delete char i of theVers

  end repeat

  put (minMCvers & "." & theVers) + 0 into minMCvers

  if mcVers < minMCvers then

    if showMsg then

        answer "Oops, this stack needs version MetaCard " & minVersion & return & \

            " or later (you're using version " & currVers & ")!" with "Quit"

    end if     

    return true

  else

    return false

  end if

end MCearlierThan

The above avoids problems when trying to use recent features not supported in earlier versions of MC.  IF you find it useful, then help yourself!

Cheers

Peter

--
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Peter Reid
Reid-IT Limited, Loughborough, Leics., UK
Tel: +44 (0)1509 268843 Fax: +44 (0)870 052 7576
E-mail: [EMAIL PROTECTED]
Web: http://www.reidit.co.uk

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