order_by() could have an error hint when confused with arrange()

[econandrew]

For those of us who sometimes have SQL on the brain...

> df <- df %>% order_by(value)
Error: `call` must be a function call, not a symbol
> df <- df %>% order_by(-value)
Error: Can't use matrix or array for column indexing
> df <- df %>% arrange(-value)

e.g. Did you mean to use arrange()?

[Lef-F]

I just stumbled upon this while trying to figure out why order_by is "not working for me today"... 😆

[hadley]

This would be relatively simple to implement — order_by() just needs to check if call is a symbol, and if so, offer a hint about arrange().

[dennet]

stumbled upon this after a long break from the tidyverse. Hint about 'arrange()' in the error message would be a nice touch.