Provide api to interpret ExprSyntax as VersionTupleSyntax

Author: StevenWong12

Sources/SwiftParser/ExpressionInterpretedAsVersionTuple.swift

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+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+@_spi(RawSyntax) import SwiftSyntax
+
+extension ExprSyntax {
+  public func asVersionTuple(with maxComponentCount: Int) -> VersionTupleSyntax? {
+    var parser = Parser(self.description)
+    let raw = parser.parseVersionTuple(maxComponentCount: maxComponentCount)
+    return Syntax(raw: raw.raw, rawNodeArena: raw.raw.arena).as(VersionTupleSyntax.self)
+  }
+}

Tests/SwiftParserTest/ExpressionInterpretedAsVersionTupleTests.swift

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+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import SwiftParser
+import SwiftSyntax
+import XCTest
+
+final class ExpressionInterpretedAsVersionTupleTest: XCTestCase {
+  func testExpressionInterpretedAsVersionTuple() throws {
+    let expression: ExprSyntax = "2.2.2.2"
+    let versionTuple = try XCTUnwrap(expression.asVersionTuple(with: 4))
+    let versionTupleComponents = try XCTUnwrap(versionTuple.components)
+    XCTAssertTrue(!versionTuple.hasError)
+    XCTAssertEqual(versionTuple.description, "2.2.2.2")
+    XCTAssertEqual(versionTuple.major.description, "2")
+    XCTAssertEqual(versionTupleComponents.description, ".2.2.2")
+  }
+}