Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!unmvax!polyslo!mlind
From: mlind@polyslo.CalPoly.EDU (Mark William Lind I)
Newsgroups: comp.lang.modula2
Subject: Re: Recursive data types
Summary: hmmmmmm....
Message-ID: <11188@polyslo.CalPoly.EDU>
Date: 9 May 89 08:04:36 GMT
References: <5734@cs.Buffalo.EDU: <1046@gmdzi.UUCP>
Reply-To: mlind@polyslo.CalPoly.EDU (Mark William Lind I)
Organization: Poly C.A.T.S.
Lines: 41

kloppen@gmdzi.UUCP (Jelske Kloppenburg) writes:
:ugprussa@cs.Buffalo.EDU (Michal Prussak) writes:

:> Wirth describes in his book "Algorithms and Data Structures" (from 1986)
:> a recursive data type (p 173):
     ^^^^^^^^^ ^^^^ ^^^^
RECURSIVE DATA TYPE ???
:> TYPE
:>    ped = RECORD
:>      CASE known: BOOLEAN OF
:>         TRUE: name: ARRAY[1..10] OF CHAR |
:>            FALSE: father, mother: ped;   <--- recursive fields
:>         END (* case *);                       ^^^^^^^^^
:>    END (* record *);
:
:That can not work...

DYNAMIC MEMORY ALLOCATION (not recursive)
:TYPE
:   LinkPTR = POINTER TO Link;
:   Link = RECORD
:             Text: String;
:             Count: CARDINAL;
:             Left, Right: LinkPTR
:   END;

This is dynamic memory allocation... but this is not a RECURSIVE
data type.  Personally, I don't see what the use of a recursive
data structure is.  Dynamic memory allocation is of obvious
worth (no pun intended), but I don't see what the hell you would
do with a recursive boolean expression?....... huh?

Please Explain if you are still there.

Hmmm...

-- 
+-------------------------------------------------------------------------+
 \  Mark William Lind I  \  mlind@polyslo.CalPoly.EDU  \  Mark L  \  8^"   \
  \  Std Disclaimer Assumed  \ "Evel Knievel, you got nothin' on me." -_R_a_e_l \  
   +-------------------------------------------------------------------------+