Adding common checks

[gaborcsardi]

Is this planned? E.g. ensure_string_scalar, ensure_file_exists, ensure_dir_exists, etc? Or the idea is that I can just add to my package whatever I need?

[smbache]

Initially this was the intention, but as I though about it I realized that the list would probably be ever-growing, and it might open up a can of worms. So I think I might keep it as simple as possible...

Also I typically find that the conditions needed are often very specific...

But this is not set in stone; have actually given it some thought :)

[gaborcsardi]

Yeah, it is a tough decision, and there might not be a perfect solution. How about having another package for common checks? I like it, that the package is clean, but I also don't want to duplicate the common checks in all my packages.

EDIT: I would be happy to create such a package, and most probably will, if you don't want to do it.

[smbache]

Do you have a list of what you would consider reusable/standard checks?

[gaborcsardi]

A reasonable list is here: https://github.com/hadley/assertthat#new-assertions assertthat is actually not bad, but the checks return a logical, and not the value itself, so you can't use them in pipes.

Another thing would be checking an enum, e.g.

f <- function(mode = c("foo", "bar", "foobar") {
  ensure_enum(mode) %>% ...
  ...
}

although this is almost the same as match.arg, but then we could have the same kind of error messages.

Others:

• ensure_integer (not is.integer)
• ensure_positive
• ensure_finite etc.

But you are right that it is hard to decide. E.g. I often need ensure_url nowadays, and I am not sure if that should be built in.

[gaborcsardi]

One solution to this is http://editorconfig.org/ Of course RStudio would need to support it....

EDIT: sorry, wrong issue.....

[smbache]

Would a solution be that you made the package, and let it evolve, then maybe it will be more clear if they are better suited in ensurer itself?

[gaborcsardi]

We can try, although I will probably put in more stuff than you would, and then you will not want to merge. :)

Btw. the assertive package is also not bad, at least it has a lot of assertions built in, but it also has a lot of other boilerplate stuff, and I am not quite comfortable with the syntax. Anyway, I'll create an ensurethat package. (Btw. suggestions for a better name are welcome. :)