[boost] Re: lexical_cast with default value

From: Kevlin Henney (kevlin_at_[hidden])
Date: 2005-05-12 08:59:31

In message <427A7A31.8000504_at_[hidden]>, Andrey Melnikov 
<melnikov_at_[hidden]> writes
>
>The purpose of lexical cast is conversion through serializaton and 
>deserialization. boost::lexical_cast is called lexical cast because it 
>uses STL object serialization framework based on << and >> operators.
>
>Semantically convert_to is a different operation.
[...]
>I think we can leave lexical_cast alone as it is, but add separate 
>functions for safe conversions between ascii and binary representation 
>of numbers. These functions should be fast and properly named according 
>to their semantic. Performance requirement can also force us to 
>implement additional interface with error flag instead of throwing 
>exceptions. convert_to<int>("abc") can be so fast that in some 
>applications overhead of throwing an exception will be very noticeable.

I think that the specialisation (conceptual as opposed to templated) 
perspective is the right way to go. lexical_cast caters for a general 
need, but not all specific needs (it is stream-based and not 
performance-centric), so functions that cater to more specific 
conversions -- convert_to with default, string_to, etc -- seem to make 
sense. It is not a load that lexical_cast should be carrying all of, 
IMHO.

Kevlin
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