Add import declaration builder

Author: akkyie

Sources/SwiftSyntaxBuilder/Declarations/Buildables/Import.swift

@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2019 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 SwiftSyntax
+
+public struct Import: DeclBuildable {
+  let moduleName: String
+
+  public init(_ moduleName: String) {
+    self.moduleName = moduleName
+  }
+
+  public func buildDecl(format: Format, leadingTrivia: Trivia) -> DeclSyntax {
+    let importToken = Tokens.import.withLeadingTrivia(leadingTrivia + format.makeIndent())
+    let moduleNameToken = SyntaxFactory.makeIdentifier(moduleName)
+
+    return ImportDeclSyntax {
+      $0.useImportTok(importToken)
+      $0.addPathComponent(AccessPathComponentSyntax {
+        $0.useName(moduleNameToken)
+      })
+    }
+  }
+}

Sources/SwiftSyntaxBuilder/Tokens/Tokens.swift

@@ -22,6 +22,9 @@ enum Tokens {
   /// `"var "`
   static let `var` = SyntaxFactory.makeVarKeyword().withTrailingTrivia(.spaces(1))
 
+  /// `"import "`
+  static let `import` = SyntaxFactory.makeImportKeyword().withTrailingTrivia(.spaces(1))
+
   /// `"struct "`
   static let `struct` = SyntaxFactory.makeStructKeyword().withTrailingTrivia(.spaces(1))
 

Tests/SwiftSyntaxBuilderTest/Declarations/ImportTests.swift

@@ -0,0 +1,25 @@
+import XCTest
+import SwiftSyntax
+
+@testable import SwiftSyntaxBuilder
+
+final class ImportTests: XCTestCase {
+  func testImport() {
+    let format = Format(indentWidth: 2).indented()
+
+    let testCases: [UInt: (Import, String)] = [
+      #line: (Import("SwiftSyntax"),
+              "  import SwiftSyntax"),
+    ]
+
+    for (line, testCase) in testCases {
+      let (builder, expected) = testCase
+      let syntax = builder.buildSyntax(format: format, leadingTrivia: .zero)
+
+      var text = ""
+      syntax.write(to: &text)
+
+      XCTAssertEqual(text, expected, line: line)
+    }
+  }
+}