Refactor P4Compiler to P4Parser

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

Sources/P4Parser/Compiler.swift

@@ -0,0 +1,57 @@
+// 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 SwiftTreeSitter
+import TreeSitterExtensions
+import TreeSitterP4
+
+let p4lang = Language(tree_sitter_p4())
+
+public func ConfigureP4Parser() -> Result<SwiftTreeSitter.Parser> {
+  let p = SwiftTreeSitter.Parser.init()
+
+  do {
+    try p.setLanguage(p4lang)
+  } catch {
+    return Result.Error(Error(withMessage: "Could not configure the P4 parser"))
+  }
+
+  return .Ok(p)
+}
+
+public func compile(_ s: String) -> Result<CST.Program> {
+  let maybe_parser = ConfigureP4Parser()
+  guard case .Ok(let p) = maybe_parser else {
+    return .Error(maybe_parser.error()!)
+  }
+
+  let result = p.parse(s)
+  guard let tree = result,
+    !tree.isError(lang: p4lang),
+    !tree.containsMissing(lang: p4lang)
+  else {
+    return Result.Error(Error(withMessage: "Could not parse the P4 program"))
+  }
+
+  guard let root = tree.rootNode else {
+    return Result.Error(Error(withMessage: "No P4 program compiled"))
+  }
+
+  let compilation_context = CSTCompilerContext()
+  return CST.Program.Parse(node: root, withContext: compilation_context)
+}