Be careful of “Smart Punctuation”

You might have known that since iOS 11, Apple has a feature called “Smart Punctuation” which has few “smart” behaviors like:

• Automatically replace quotation mark like `U+0022` to whatever quotation marks in your language like `U+201C`.
• Automatically replace double hyphen `U+002D` to a em-dash `U+2014`
• Automatically insert an extra space after a paste operation or delete one or two spaces after a cut or delete operation.

Users can of course disable these features in Settings app.

Programmatically you can also disable them by setting :

someTextInput.smartQuotesType = .no
someTextInput.smartDashesType = .no
someTextInput.smartInsertDeleteType = .no

(Both TextField and TextView conform to `UITextInputTraits`)

So the unexpected part is, even if you set these properties for your input, you would still see “Smart Punctuation” happens when you call API like:

UITextView.replace(_ range: UITextRange, withText text: String)

Too smart … I would say.