Re: [boost] Formal Review Request: Boost.String.Convert

Subject: Re: [boost] Formal Review Request: Boost.String.Convert
From: Vladimir Batov (batov_at_[hidden])
Date: 2009-02-18 06:55:55

>>     convert::to<wstring>
>
> Why not just convert_to<wstring>?
>
> Is the problem with convert by itself that it leaves the reader worrying
> about 'to' and/or 'from'?
>
> - leaving one feeling 'what?'
>
> Direction matters.

Yes, once I got comfortable with boost::convert::to I realized that after 
generalization the 'from' is obviously redundant as string-from-int can 
always be transformed to int-to-string. So, 'from' died out. When only 'to' 
left, I asked myself what it was doing on its own.

I do agree in principle that having direction helps (even only somewhat) but 
'to' does not seem to work. It all starts nicely:

    string s = boost::convert::to<int>(-1)

Above 'to' does seem natural (IMHO of course) as the line kind of reads as 
"convert to int". However, with the default parameter it becomes

    string s = boost::convert::to(-1, "failed to convert")

i.e. 'to' becomes a nuisance. In that setting I much prefer

    string s = boost::convert(-1, "failed to convert")

which answers the "convert what" question as it reads as "convert int". 
Granted, the conversion destination becomes somewhat subtle. However, I do 
not feel it is too subtle to get one confused. More so, I feel the convert 
family is well discriminated (with enable_if) so that

    Wstring WIDE_str = boost::convert(-1, "failed to convert")

will not compile. Therefore, I feel very safe with just

    string s = boost::convert(-1, "failed to convert").

That thought took me all the way from boost::string::convert() to 
boost::convert(). That looks like a reasonable and logical compromise which 
might not be as nice as "convert::to<int>" but overall holds better. I am OK 
with that. Others..?

V.