Refactor

Refactor into four major components:

1. Common: Things shared among all other components.
2. Lang: P4-language-related components.
3. Runtime: Components required to run a P4 program.
4. Parser: Components for parsing a P4 program from source.

Other components:

1. Macros
2. Tests
3. TreeSitterExtensions: Extra tree sitter functionality

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

Sources/Runtime/Runtime.swift

@@ -0,0 +1,58 @@
+// p4rse, Copyright 2026, Will Hawkins
+//
+// This file is part of p4rse.
+//
+// This file is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import Common
+import Lang
+
+public class ParserRuntime: CustomStringConvertible {
+  var execution: ParserExecution
+
+  init(execution: ParserExecution) {
+    self.execution = execution
+  }
+
+  public static func create(program: Lang.Parser) -> Result<ParserRuntime> {
+    switch ParserExecution.create(program) {
+    case .Ok(let execution): return .Ok(Runtime.ParserRuntime(execution: execution))
+    case .Error(let error): return .Error(error)
+
+    }
+  }
+
+  public func run(input: Packet) -> Result<(ParserState, ProgramExecution)> {
+    execution.scopes.enter()
+    return .Ok(execution.execute())
+  }
+
+  public var description: String {
+    //return "\(super.description)\nState: \(execution?.description ?? "N/A")\nError: \(error?.description ?? "None")"
+    return "Runtime:\nExecution: \(execution)"
+  }
+}
+
+extension ParserExecution: Execution {
+  public func execute() -> (ParserState, ProgramExecution) {
+    var execution = self as ProgramExecution
+    var state = self.state
+
+    // Evaluate until the state is either accept or reject.
+    while state != accept && state != reject {
+      (state, execution) = self.state.evaluate(execution: execution)
+    }
+    return (state, execution)
+  }
+}