Re: [Boost-users] [BGL] how to actually search with DFS/BFS?

From: Thomas Costa (oohrah_at_[hidden])
Date: 2005-06-22 12:50:13

Will a future version of BGL have a "TerminatorFunc" in all the  
visitor types?

Throwing an exception as part of the "normal" flow of an algorithm  
seems to go against most people's C++ philosophy.

On 22 Jun 2005, at 9:44 AM, Doug Gregor wrote:

>
> On Jun 13, 2005, at 9:23 AM, martin f krafft wrote:
>
>
>> This may seem like a silly question, but how does one actually
>> search with DFS or BFS? Say I want to find the first node for which
>> a predicate returns true in a BFS traversal starting at node N...
>>
>> The function signatures don't have a parameter for "criteria" or
>> "predicate", so I guess it's up for a Visitor to implement such
>> a check. What is not clear to me is how the visitor functions can
>> break out of the search once a condition is true.
>>
>
> The typical way we handle this is to write a visitor that checks the
> predicate and, when it returns "true" just throw an exception.
> depth_first_visit actually has a "TerminatorFunc" parameter that does
> what you want, but it isn't present in the other search algorithms
> (although it probably should be).
>
>     Doug
>
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