[llvm-dev] RFC: General purpose type-safe formatting library

Zachary Turner via llvm-dev llvm-dev at lists.llvm.org
Wed Oct 12 07:03:20 PDT 2016


I'm not sure that would work well. The implementation relies on being able
to index into the parameter pack. How would you do that if each parameter
is streamed in?

"{0} {1}"_fs(1, 2)

Could perhaps work, but it looks a little strange to me.

Fwiw i agree format_string is long. Ideally it would be called format, but
that's taken.

Another option is os.format("{0}", 7), and have format_string("{0}", 7)
return a std::string.
On Wed, Oct 12, 2016 at 6:43 AM Aaron Ballman <aaron at aaronballman.com>
wrote:

> >> 1. os << format_string("Test");   // writes "test"
> >> 2. os << format_string("{0}", 7);  // writes "7"
> >
> >
> > The "<< format_string(..." is ... really verbose for me. It also makes me
> > strongly feel like this produces a string rather than a streamable
> entity.
>
> I wonder if we could use UDLs instead?
>
> os << "Test" << "{0}"_fs << 7;
>
> ~Aaron
>
> >
> > I'm not a huge fan of streaming, but if we want to go this route, I'd
> very
> > much like to keep the syntax short and sweet. "format" is pretty great
> for
> > that. If this is going to fully subsume its use cases, can we eventually
> get
> > that to be the name?
> >
> > (While I don't like streaming, I'm not trying to fight that battle
> here...)
> >
> > Also, you should probably look at what is quickly becoming a popular C++
> > library in this space: https://github.com/fmtlib/fmt
> >
> > _______________________________________________
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> > llvm-dev at lists.llvm.org
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> >
>
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