appendInterpolation(_:)
Interpolates the given value’s textual representation into the string literal being created.
Declaration
mutating func appendInterpolation<T>(_ value: T) where T : CustomStringConvertible, T : TextOutputStreamableDiscussion
You don’t need to call this method directly. It’s used by the compiler when interpreting string interpolations. Instead, use string interpolation to create a new string by including values, literals, variables, or expressions enclosed in parentheses, prefixed by a backslash (\(…)).
let price = 2
let number = 3
let message = """
If one cookie costs \(price) dollars, \
\(number) cookies cost \(price * number) dollars.
"""
print(message)
// Prints "If one cookie costs 2 dollars, 3 cookies cost 6 dollars."