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From: mr@hou2h.UUCP (M.RINDSBERG)
Newsgroups: net.lang
Subject: Re: Recursion
Message-ID: <1045@hou2h.UUCP>
Date: Thu, 12-Sep-85 11:46:59 EDT
Article-I.D.: hou2h.1045
Posted: Thu Sep 12 11:46:59 1985
Date-Received: Fri, 13-Sep-85 04:22:40 EDT
References: <250@mot.UUCP>, <4302@alice.UUCP>
Organization: AT&T Bell Labs, Holmdel NJ
Lines: 21

>
>>>     I think that would be a good idea, but wouldnt it be limited to direct
>>> recursion ( i.e. routine A calls A as apposed to A calls B, B calls A ). I
>>> don't know PL/I, but I would think including such a check for anything other
>>> than direct recursion would be a royal pain for a compiler writter.
>>> 
>> Actually, it's not too bad.  You just set up an n-by-n Boolean matrix
>> where n is the number of subroutines under consideration and the
>> ij element is 1 iff routine i calls routine j.  Then take the
>> transitive closure by Warshall's algorithm.  1's on the diagonal of
>> the result indicate which routines are indirectly recursive.
>
>This uses up memory proportional to the square of the
>number of subroutines.  Not a good idea.
>

This doesnt really use up memory.
Only during compilation.
It may take time, though.

					Mark