Add import tag

Sources/StencilSwiftKit/Environment.swift

@@ -55,6 +55,7 @@ private extension Extension {
     registerTag("macro", parser: MacroNode.parse)
     registerTag("call", parser: CallNode.parse)
     registerTag("map", parser: MapNode.parse)
+    registerTag("import", parser: ImportNode.parse)
   }
 }
 

Sources/StencilSwiftKit/ImportNode.swift

@@ -0,0 +1,38 @@
+//
+// StencilSwiftKit
+// Copyright © 2022 SwiftGen
+// MIT Licence
+//
+
+import Stencil
+
+internal final class ImportNode: NodeType {
+  let templateName: Variable
+  let token: Token?
+
+  class func parse(_ parser: TokenParser, token: Token) throws -> NodeType {
+    let components = token.components
+    guard components.count == 2 else {
+      throw TemplateSyntaxError("'import' tag requires one argument, the template file to be imported.")
+    }
+
+    return ImportNode(templateName: Variable(components[1]), token: token)
+  }
+
+  init(templateName: Variable, token: Token? = nil) {
+    self.templateName = templateName
+    self.token = token
+  }
+
+  func render(_ context: Context) throws -> String {
+    guard let templateName = try self.templateName.resolve(context) as? String else {
+      throw TemplateSyntaxError("'\(self.templateName)' could not be resolved as a string")
+    }
+
+    let template = try context.environment.loadTemplate(name: templateName)
+    _ = try template.render(context)
+
+    // Import should never render anything
+    return ""
+  }
+}