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If a function builder contains a buildIf function, then "if" statements will be supported by passing an optional of the "then" branch. "if" statements with an "else" statement are unsupported at present.
58 lines
1.2 KiB
Swift
58 lines
1.2 KiB
Swift
// RUN: %target-run-simple-swift | %FileCheck %s
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// REQUIRES: executable_test
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@_functionBuilder
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struct TupleBuilder {
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static func buildBlock<T1, T2>(_ t1: T1, _ t2: T2) -> (T1, T2) {
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return (t1, t2)
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}
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static func buildBlock<T1, T2, T3>(_ t1: T1, _ t2: T2, _ t3: T3)
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-> (T1, T2, T3) {
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return (t1, t2, t3)
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}
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static func buildBlock<T1, T2, T3, T4>(_ t1: T1, _ t2: T2, _ t3: T3, _ t4: T4)
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-> (T1, T2, T3, T4) {
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return (t1, t2, t3, t4)
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}
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static func buildBlock<T1, T2, T3, T4, T5>(
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_ t1: T1, _ t2: T2, _ t3: T3, _ t4: T4, _ t5: T5
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) -> (T1, T2, T3, T4, T5) {
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return (t1, t2, t3, t4, t5)
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}
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static func buildDo<T>(_ value: T) -> T { return value }
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static func buildIf<T>(_ value: T?) -> T? { return value }
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}
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func tuplify<T>(_ cond: Bool, @TupleBuilder body: (Bool) -> T) {
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print(body(cond))
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}
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// CHECK: (17, 3.14159, "Hello, DSL", (["nested", "do"], 6), Optional((2.71828, ["if", "stmt"])))
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let name = "dsl"
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tuplify(true) {
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17
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3.14159
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"Hello, \(name.map { $0.uppercased() }.joined())"
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do {
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["nested", "do"]
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1 + 2 + 3
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}
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if $0 {
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2.71828
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["if", "stmt"]
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}
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}
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// CHECK: ("Empty optional", nil)
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tuplify(false) {
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"Empty optional"
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if $0 {
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2.71828
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["if", "stmt"]
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}
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}
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