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From: liberte@uiucdcsb.CS.UIUC.EDU
Newsgroups: net.lang.forth
Subject: Re: Mutual recursion in Forth
Message-ID: <9100007@uiucdcsb>
Date: Fri, 14-Mar-86 18:23:00 EST
Article-I.D.: uiucdcsb.9100007
Posted: Fri Mar 14 18:23:00 1986
Date-Received: Sun, 16-Mar-86 08:47:10 EST
References: <426@ucbjade.BERKELEY.EDU>
Lines: 21
Nf-ID: #R:ucbjade.BERKELEY.EDU:426:uiucdcsb:9100007:000:684
Nf-From: uiucdcsb.CS.UIUC.EDU!liberte    Mar 14 17:23:00 1986


I implemented indirect recursion in Forth once upon a time.
I used a Forward defining word for those routines which would be
used before being fully declared.  At execution time, the forwarded
word would dynamically look up its name in the dictionary for the
most recent version of itself and then replace the reference to the
forward definition to a reference to the most recent version.  Thereafter,
the most recent version is used directly.  

For the "married" functions from "Godel, Escher, Bach", p 137 (assuming
direct recursion is also allowed):

forward m
: f dup 1 - f m - ;
: m dup 1 - m f - ;


Dan LaLiberte
liberte@b.cs.uiuc.edu
liberte@uiuc.csnet
ihnp4!uiucdcs!liberte