Re: Re: [BGL] Best way to abort an algorithm from withi n a visitor?

I suppose you're right. Point well taken. "Mark Storer" wrote in message news:E840F0B7E6189547BDB91DA8BF2228AB016255F9@csmail.cardiff.com...

Using exceptions in this way just bugs me. Religious reasons I guess. As the Esteemed Mr. Hylsop ;) mentioned earlier, exceptions are for "oops". This seems alot like the whole "do{}while(0)" with various 'break' statements sprinkled in to avoid multiple returns/nested ifs. Useful, but Just Not Right.

Your code has cooties! Nobody's going to want to sit next to it during recess...

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So there's no way to affect feedback to the algorithm's dispatcher without actually making modifications to the algorithm code.

So modify away. Seems like a "breath_first_until" sort of thing would be quite useful. Pass in some sort of predicate, and away you go. I'm sure the community at large would be grateful.

--Mark Storer Software Engineer Cardiff Software

#include <disclaimer> typedef std::disclaimer<Cardiff> Discard;

-----Original Message----- From: Chris Russell [mailto:cdr@encapsule.com] Sent: Wednesday, September 18, 2002 1:27 PM To: boost-users@yahoogroups.com Subject: [Boost-Users] Re: [BGL] Best way to abort an algorithm from withi n a visitor?

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Now if you've got more than a hundred or so entries left to go, exceptions really are the greener grass.

The size of the graph is not known a-priori (not at coding time anyway) but is likely to be quite large.

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What's wrong with 'return', perhaps along-side some sort of 'done' status variable? I'm only vaguely familiar with the visitor pattern, but these would seem to be the obvious choice.

See my earlier reply. In this case I'm deriving my visitor from a base and overriding "event" handlers that receive their marching orders via const references and return void. So there's no way to affect feedback to the algorithm's dispatcher without actually making modifications to the algorithm code.

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If efficiency is your goal, exceptions are not the answer. Just enabling exceptions at compile time makes a noticable performance hit. Actually throwing an exception can gobble up a 1000 cycles, give or take. That's

"Mark Storer" wrote in message news:E840F0B7E6189547BDB91DA8BF2228AB016255F8@csmail.cardiff.com... per

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throw. If you catch and throw again, you'll pay again.

Now if you've got more than a hundred or so entries left to go, exceptions really are the greener grass.

What's wrong with 'return', perhaps along-side some sort of 'done' status variable? I'm only vaguely familiar with the vistor pattern, but these would seem to be the obvious choice.

--Mark Storer Software Engineer Cardiff Software

#include <disclaimer> typedef std::disclaimer<Cardiff> Discard;

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