🚀 go-pugleaf

JRS:  In article <dqmv68.8f1.ln@bastisoft.de> of Sat, 29 Jan 2000
22:41:33 in news:comp.lang.pascal.borland, Sebastian Koppehel
<un0100@bastisoft.de> wrote:
>I agree that crossover recursion can be dangerous, but sometimes it
>makes sense. Whether or not you lose track depends on how clear you
>write the procedures themselves.
>
>My all-time favourite (not intended for actual use):
>
>   function Odd(n : Integer) : Boolean; forward;
>   
>   function Even(n : Integer) : Boolean;
>   begin
>      if n = 0 then Even := true
>      else Even := Odd(n - 1);
>   end;
>   
>   function Odd(n : Integer) : Boolean;
>   begin
>      if n = 0 then Odd := false
>      else Odd := Even(n - 1);
>   end;

Very elegant, as an example possessing crystal clarity combined with no
practical use whatsoever, except maybe to test stack overflow handling.

I am currently polishing a TP7 program - there is already a working
copy, CHEKLINX (PAS (needs VERSION) & EXE), on my WWW site (Sig Line 3)
- which uses mutually recursive procedures.  The program is a relative
links checker for the local DOS master of a WWW site: proc T is given a
presumed file name, and, unless the file has already been done, checks
its existence and if appropriate reads it and calls proc V; V loops
through the links, and, for each, checks the destination from stored
information, calling T if the file is not yet read.  Readers are welcome
to try it, having read the comment starting the PAS.  It also works with
Delphi 3 "DCC32 -cc".

In this case, ISTM that the procedures could have been combined, with a
distinct loss of clarity.

CHEKLINX found several link errors, now fixed, on my site.

FL & others : please see end of Section 1 of c.l.p.b mini-FAQ; NGs re-
ordered.
 
-- 
� John Stockton, Surrey, UK.  jrs@merlyn.demon.co.uk   Turnpike v4.00   MIME. �
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