Is it possible to preview github.com/shopspring/decimal values in VSCode during debugging?

Question

This is a preview of a normal int64/float64 variable in Go in vscode during debugging.

And this is how it looks when using a variable from Decimal library.

If that would be possible then debugging would be so much easier. Right now, being a value is not possible without logs and if there are no logs you need to rebuild and restart the project.

Any ideas of how to achieve it - maybe a plugin or some kind of expression? Or maybe someone knows how to write a plugin/extension for that?

Basically to see the value we need to call. var.String() function but it is not possible to call function during viscose debugging. Or I just don't know how.

I have been using this arbitrary-precision package called Decimal (https://github.com/shopspring/decimal) for years and this was a pain and I finally want to make it work.

Yes, in this example you can click expand 3 times then take the value 2345454 and take exp:-3 and just put a dot there in your head and get 2345.453 but this is not ideal and I think it does not always work anyway, especially hard with below-zero values.

Answer 1

Expand @icza's comment.

call fff.String() does not work for github.com/shopspring/decimal on my computer. It errors with:

(dlv) call t.String()
> main.main() ./main.go:20 (PC: 0x49ecbf)
Command failed: write out of bounds

My system is linux/amd64. And I think it does not work on all 64bit systems.

There is a bug in the current version of dlv (1.20.2). I just filed a bug report and sent a fix.

Update:

The fix has been merged. You can update dlv to get this fix:

$ go install github.com/go-delve/delve/cmd/dlv@master

Here is the result with this fix: