Support Parameters For Parsers

Signed-off-by: Will Hawkins <hawkinsw@obs.cr>

Sources/P4Lang/Declarations.swift

@@ -18,3 +18,38 @@
 import Common
 
 public struct Declaration {}
+
+public struct Parameter: CustomStringConvertible {
+  public var name: Identifier
+  public var type: P4Type
+
+  public init(
+    identifier: Identifier, withType type: P4Type
+  ) {
+    self.name = identifier
+    self.type = type
+  }
+
+  public var description: String {
+    return "Parameter: \(self.name) with type \(self.type)"
+  }
+}
+
+public struct ParameterList: CustomStringConvertible {
+  public var parameters: [Parameter]
+
+  public init(_ parameters: [Parameter]) {
+    self.parameters = parameters
+  }
+
+  public func addParameter(_ parameter: Parameter) -> ParameterList {
+    return ParameterList(self.parameters + [parameter])
+  }
+
+  public var description: String {
+    let parameters = self.parameters.map { parameter in
+      parameter.description
+    }.joined(separator: ";")
+    return "Parameter list: \(parameters)"
+  }
+}