public async Task what_i_desire_EitherAsync()
{
EitherAsync <Error, Pixel> GetPixelE(PixelId id) =>
GetPixel(id).ToEither(Error.New("pixel not found"));
var program =
from pixel in GetPixelE(PixelId.New("wkrp"))
from id in GenerateLinkId(pixel.Value)
from resource in ScrapeUrl("http://google.com")
select resource;
await program.Match(
Right : r => Assert.True(false, "this should not pass"),
Left : e => Assert.Equal("pixel not found", e.Value)
);
}
public async Task what_im_forced_to_do()
{
var program =
from pixel in GetPixel(PixelId.New("wkrp")).AsTry("pixel not found")
from id in GenerateLinkId(pixel.Value).AsTry()
from resource in ScrapeUrl("http://google.com").AsTry()
select resource;
(await program.Try()).Match(
Succ: r =>
{
Assert.True(false, "this should not pass");
return(unit);
},
Fail: e =>
{
Assert.Equal("pixel not found", e.Message);
return(unit);
}
);
}
public static EitherAsync <Error, string> GenerateLinkId(PixelId pixelId) =>
Right <Error, string>($"{pixelId}-1234").ToAsync();
public static OptionAsync <Pixel> GetPixel(PixelId id) => Option <Pixel> .None.ToAsync();
public static Task <Either <Error, string> > GenerateLinkId(PixelId pixelId) =>
Task.FromResult(Right <Error, string>($"{pixelId}-1234"));
public static Task <Option <Pixel> > GetPixel(PixelId id) => Task.FromResult(Option <Pixel> .None);