import Foundation

// A Swift string is a collection of Unicode characters.
// Swift uses Unicode scalars as its fundamental unit,
// which is similar to the concept of runes in other languages.

// `s` is a `String` assigned a literal value
// representing the word "hello" in the Thai language.
// Swift string literals are Unicode-encoded text.
let s = "สวัสดี"

// This will produce the number of characters in the string.
print("Character count:", s.count)

// This loop generates the Unicode scalar values of all
// the characters in `s`.
for scalar in s.unicodeScalars {
    print(String(format: "%x ", scalar.value), terminator: "")
}
print()

// To count how many Unicode scalars are in a string, we can use
// the `unicodeScalars` property. Note that some Thai characters
// are represented by Unicode scalars that can span multiple bytes.
print("Unicode scalar count:", s.unicodeScalars.count)

// A `for` loop handles strings specially and iterates
// over each character along with its offset in the string.
for (index, character) in s.enumerated() {
    print("\(character) starts at \(index)")
}

print("\nUsing unicodeScalars")
// We can achieve a similar iteration by using the
// `unicodeScalars` property explicitly.
for (index, scalar) in s.unicodeScalars.enumerated() {
    print("\(scalar) starts at \(index)")
    examineCharacter(scalar)
}

// This demonstrates passing a `Character` value to a function.
func examineCharacter(_ scalar: Unicode.Scalar) {
    // We can compare a `Unicode.Scalar` value to a character literal directly.
    if scalar == "t" {
        print("found tee")
    } else if scalar == "ส" {
        print("found so sua")
    }
}