std.conv:to that does not throw?

[H. S. Teoh]

On Wed, Jan 29, 2025 at 07:08:49PM -0700, Jonathan M Davis via Digitalmars-d-learn wrote:
> On Wednesday, January 29, 2025 6:38:07 PM MST Kyle Ingraham via Digitalmars-d-learn wrote:
> > Does D have a 'try' `std.conv:to` that does not throw if it fails?
> > Something like:
> > ```D
> > string input = "9";
> > int output;
> > auto parsed = input.tryTo!int(output);
> > ```
> >
> > `std.conv:to` is super flexible and does exactly what I need.
> > However, hitting an exception for conversion failures really slows
> > down my code. A conversion failure wouldn't be an exception for my
> > use case. I'm trying to write web application route constraint code
> > like what's [available in
> > C#](https://github.com/dotnet/aspnetcore/blob/main/src/Http/Routing/src/Constraints/IntRouteConstraint.cs#L53).
> > There, code like `Int.TryParse` is used to figure out whether a
> > string meets a route constraint.
> >
> > `std.conv:to` is almost perfect with it's flexibility across types.
> > I'm just hoping I've missed the version that doesn't throw.
> 
> Unfortunately, there isn't currently a function like std.conv.to which
> does not throw.

I thought std.conv.parse* is supposed to fill that role?  Or am I
remembering wrong?  They don't quite have the same level of convenience
as .to, though.


--T

-- 
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