// RUN: %target-run-simple-swift | %FileCheck %s
// REQUIRES: executable_test

@_functionBuilder
struct TupleBuilder {
  static func buildBlock<T1, T2>(_ t1: T1, _ t2: T2) -> (T1, T2) {
    return (t1, t2)
  }
  
  static func buildBlock<T1, T2, T3>(_ t1: T1, _ t2: T2, _ t3: T3)
      -> (T1, T2, T3) {
    return (t1, t2, t3)
  }

  static func buildBlock<T1, T2, T3, T4>(_ t1: T1, _ t2: T2, _ t3: T3, _ t4: T4)
      -> (T1, T2, T3, T4) {
    return (t1, t2, t3, t4)
  }

  static func buildBlock<T1, T2, T3, T4, T5>(
    _ t1: T1, _ t2: T2, _ t3: T3, _ t4: T4, _ t5: T5
  ) -> (T1, T2, T3, T4, T5) {
    return (t1, t2, t3, t4, t5)
  }

  static func buildDo<T>(_ value: T) -> T { return value }
  static func buildIf<T>(_ value: T?) -> T? { return value }
}

func tuplify<T>(_ cond: Bool, @TupleBuilder body: (Bool) -> T) {
  print(body(cond))
}

// CHECK: (17, 3.14159, "Hello, DSL", (["nested", "do"], 6), Optional((2.71828, ["if", "stmt"])))
let name = "dsl"
tuplify(true) {
  17
  3.14159
  "Hello, \(name.map { $0.uppercased() }.joined())"
  do {
    ["nested", "do"]
    1 + 2 + 3
  }
  if $0 {
    2.71828
    ["if", "stmt"]
  }
}

// CHECK: ("Empty optional", nil)
tuplify(false) {
  "Empty optional"
  if $0 {
    2.71828
    ["if", "stmt"]
  }
}