Refactor P4Compiler to P4Parser

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

Sources/P4Parser/Feedback.swift

@@ -0,0 +1,33 @@
+// 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
+
+public struct CompilationFeedback {
+  public let feedback: String
+
+  static func markup(
+    _ source: SourceCode, _ errors: [any Errorable], _ formatter: any Formattable
+  ) -> String {
+    errors.map { $0.format(formatter, source) }.joined(separator: "\n")
+  }
+
+  public init(_ source: SourceCode, _ errors: [any Errorable], _ formatter: any Formattable) {
+    self.feedback = Self.markup(source, errors, formatter)
+  }
+
+}