Path: utzoo!attcan!uunet!mcvax!ukc!cam-cl!cet1 From: cet1@cl.cam.ac.uk (C.E. Thompson on jenny) Newsgroups: comp.lang.postscript Subject: Re: Interesting Bug Message-ID: <873@scaup.cl.cam.ac.uk> Date: 17 Aug 89 17:40:05 GMT Sender: news@cl.cam.ac.uk Reply-To: cet1@cl.cam.ac.uk (C.E. Thompson) Organization: U of Cambridge Comp Lab, UK Lines: 26 In article <2106@optilink.UUCP>, cramer@optilink.UUCP (Clayton Cramer) describes the infinite loop caused by /L {L} def % ... L and in article <4079@shlump.nac.dec.com>, batcheldern@level.dec.com (Ned Batchelder) explains how execstackoverflow is avoided by PostScript's tail recursion removal (documented in the footnote on page 41 of the Red Book, by the way). It may be worth pointing out that there a couple of ways (at least) of getting out of the loop, short of pulling the plug on the LW. Firstly, if a job time limit has been set by 'setjobtime' (or the eerom default has been set nonzero), then the timeout will be effective in this situation. Alternatively, an ETX (ctrl/C) character on the input port will generate at 'interrupt' error. Of course, these techniques are equally effective with other loops, such as {} loop Chris Thompson JANET: cet1@uk.ac.cam.phx Internet: cet1%phx.cam.ac.uk@nsfnet-relay.ac.uk