Re: [boost] [lexical_cast] A suggestion

Subject: Re: [boost] [lexical_cast] A suggestion
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2009-02-07 05:25:17

Scott McMurray wrote:

> One very clear use:
> 
> if (optional<int> oi = lexical_cast<optional<int> >(mystring)) {
>     int i = *oi;
>     ... use i ...
> } else {
>     ... parse failed ...
> }
> 
> And if you want defaults:
> 
> int i = -1;
> if (optional<int> oi = lexical_cast<optional<int> >(mystring)) {
>     i = *oi;
> }
> ... use i ...
> 
> Or, using the helper:
> 
> int i = lexical_cast<optional<int> >(mystring).get_value_or(-1);
> 
> Why is this so bad?

Like I said:

1. It is longer and more clumsy than lexical_cast< int >(str, 1). It 
does introduce enough scaffolding that user has to type to avoid 
lexical_cast altogether in such cases.
2. It introduces dependency on optional.
3. It bans lexical_casting optionals.