Misleading and hard to use error messages
In the following message 
```
Thanks for all answers and sorry for the late reply.

At first I tried creating new overloads semi-ignored the HSlice problem. Semi-ignored because now the '..' and related operators from system always return a HSlice instead of a slice, even if both sides are regular indexes. So I changed the type to accept HSlice[SomeInteger, SomeInteger], but not the implementation. This satisfied me for a while, but now I came back to implement the BackwardsIndex for slices and the previous overload solution simply doesn`t scale well. I then used jypayne link to see how that change was made in the standard library, and found the `^^` helper template, that is indeed very useful.

..code-block:: nim
	type SomeIndex = SomeInteger | BackwardsIndex

	template `^^`(s, i: untyped): untyped =
	  (when i is BackwardsIndex: s.len - int(i) else: int(i))

Using them updating the functions is just a matter of updating the index/bounds type and prepending `s^^` (or whatever the name of your first argument) to every use of the index/bounds type. No overloading needed, just two functions for indexing (and one for slicing):

```

The forum gives the error:

```input(7, 18) Error: '`' expected```

In the preview window. W/o experience, it took me several minutes to correct it.

Besides the error being about the wrong thing, it cites a line and a column, and there is neither line nor column indications in the editing window. It is even more annoying because when switching back and forth between the preview and the editing views, the forum won't remember the size of the editing box, that unlike github doesn't resize automatically with the text size either. It remains in it's default too small size.

By the way, while a preview is an advancement, I much preferred the old forum software, with pages, functional w/o javascript, better styling IMHO, etc. It's also ugly and unintuitive the way to go back to the main page of the forum, IMHonestO. Some text would help.