Making Copies of Lists

Date:    Mon, 13 Feb 1995 20:36:01 +0000
From:    Peter Small 
Subject: Confusion with lists

If anybody else has been confused by saving lists, they might want to put this handler in a button script and see the results in the message box.

 
on mouseUp
 
  --Create a list
  set AList to []
  put "An empty AList looks like:" && Alist & return
 
  --Fill the list up with 20 random inserts
  repeat with i = 1 to 20
    append Alist,100 +random(99)
  end repeat
 
  --Look at the list created
  put "AList is a list = " & listp(Alist)
  put "Alist looks like:" && AList & return
 
  --Look at a straight copy
  put AList into AListCopy
  put "AListCopy is a list = " & listp(AlistCopy)
  put "AlistCopy looks like:" && AListCopy  & return
 
 
  --Look at the value of AList
  put "The value of AList looks like:" && the value of AList & return
 
  put the value of Alist into AListVal
  put "AListVal is a list = " & listp(AlistVal)
  put "AlistVal looks like:" && AListVal  & return
 
  --Copy the variable containing the value
  put AListVal into AListValCopy
  put "AListValCopy is a list = " & listp(AlistValCopy)
  put "AlistValCopy looks like:" && AListValCopy & return
 
  --Now do as page 213 of manual suggests (pointed out by Matt Caldwell)
  put value(string(Alist)) into AListStringCopy
  put "AListStringCopy is a list = " & listp(AlistStringCopy)
  put "AlistStringCopy looks like:" && AListStringCopy  & return
 
  --Try out Roger Jones's sugestion
  set RogersAnswer = AList * 1
  put "RogersAnswer is a list = " & listp(RogersAnswer)
  put "RogersAnswer looks like:" && RogersAnswer  & return
 
  --See what happens when something is added to the end of AList
  append(Alist,"Changed")
  put "Alist now looks like:" && AList & return
  put "AlistCopy now looks like:" && AListCopy  & return
  put "The value of AList now looks like:" && the value of AList  & return
  put "AlistValCopy now looks like:" && AListValCopy  & return
  put "AlistStringCopy now looks like:" && AListStringCopy  & return
  put "RogersAnswer now looks like:" && RogersAnswer  & return
 
  if getLast(AlistStringCopy) <> "Changed" then
    put return & "Next time I have a problem, look at the manual before I consult the experts in DIRECT-L"
  end if
 
  if getLast(RogersAnswer) <> "Changed" then
    put return & "How, in the name of Heaven, did Roger Jones suss that one out?"
  end if
end