Add TODO comment to "not implemented" panic line

[philippgille]

TODO comments can be highlighted by IDEs (some native, some with extensions) or even collected into a task list by some. So adding this line by default to each "not implemented" panic line can help keeping an overview of the functions that still need to be implemented.

Closes #31

[josharian]

What do you think about just changing the function body to panic("TODO")? Would that have the beneficial effects you seek? See also the discussion in golang/go#35386, in which it appears that many folks already use panic("TODO").

[philippgille]

We discussed this in #31 and I thought you already agreed to my proposal. Part of my reasoning for my specific proposal is #31 (comment).

in which it appears that many folks already use panic("TODO")

Going through the comments on that issue I can't find a clear indicator for that. Most discussion focuses on the ... part I think. bradfitz does say:

as if you wrote, say, panic("TODO")

But I think that's just an example. He says the ... is inspired by Perl 6 / Raku, which fails with the message Stub code executed. Kotlin's TODO(), which ins mentioned in the comments, throws a NotImplementedError.

Then there are the IDEs, where for example the VS Code extensions TODO Highlight and TODO Parser use TODO: by default, not TODO. Eclipse does the same. So a user would have to modify the options to get proper TODO hightighting / lists in his IDE.

But we can wait for more comments on the discussion in the golang issue, maybe more people will comment on what ... should be turned into by the compiler, in case they agree that using ... for that is useful and not confusing.

[josharian]

We discussed this in #31

Oh, I apologize. I completely forgot about that.

[philippgille]

Thanks!