common, codegen: Implement Visitor And Use For CodeGen

Implement a generic visitor for components of a P4 program and use
it to start P4 code generation (according to the behavioral model).

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

Sources/Cli/main.swift

@@ -18,6 +18,7 @@
 import ArgumentParser
 import Common
 import P4Compiler
+import P4Runtime
 import SystemPackage
 
 @main
@@ -26,7 +27,7 @@ struct Cli: ParsableCommand {
 
   static let configuration = CommandConfiguration(
     abstract: "P4CE compiler, interpreter and debugger.",
-    subcommands: [Compile.self])
+    subcommands: [Compile.self, CodeGen.self])
 }
 
 struct CliOptions: ParsableArguments {
@@ -50,30 +51,72 @@ extension Cli {
       let prep = SourceCodePreprocessor(sm)
       let file = FilePath(options.path)
 
-      let maybe_source = prep.preprocess(file)
-      guard case .Ok(let source) = maybe_source else {
-        let formatter = FormatterAnsi()
-        print(ErrorWithLabel("Preprocessor Error", maybe_source.error()!).format(formatter))
-        return
-      }
-
-      let maybe_program = Program.Compile(source.getSource())
-      guard case .Ok(_) = maybe_program else {
-        let formatter = FormatterAnsi()
-        print(ErrorWithLabel("Compiler Error", maybe_source.error()!).format(formatter))
-        return
-      }
-
-      let success_formatter: any Formattable =
+      let formatter: any Formattable =
         if parent.plain != 0 {
           FormatterPlain()
         } else {
           FormatterAnsi()
         }
 
+      let maybe_source = prep.preprocess(file)
+      guard case .Ok(let source) = maybe_source else {
+        print(ErrorWithLabel("Preprocessor Error", maybe_source.error()!).format(formatter))
+        return
+      }
+
+      let maybe_program = Program.Compile(source.getSource())
+      guard case .Ok(_) = maybe_program else {
+        print(ErrorWithLabel("Compiler Error", maybe_source.error()!).format(formatter))
+        return
+      }
+
       print(
-        success_formatter.formatWithStyle(
+        formatter.formatWithStyle(
           "Success", Style(StyleColor.Green, [StyleFormat.Underline])))
     }
   }
 }
+
+extension Cli {
+  struct CodeGen: ParsableCommand {
+    static let configuration = CommandConfiguration(abstract: "Generate P4CE code.")
+
+    @ParentCommand var parent: Cli
+
+    @OptionGroup var options: CliOptions
+
+    mutating func run() {
+      let sm = SourceManager(options.search.map { FilePath($0) })
+      let prep = SourceCodePreprocessor(sm)
+      let file = FilePath(options.path)
+
+      let formatter: any Formattable =
+        if parent.plain != 0 {
+          FormatterPlain()
+        } else {
+          FormatterAnsi()
+        }
+
+      let maybe_source = prep.preprocess(file)
+      guard case .Ok(let source) = maybe_source else {
+        print(ErrorWithLabel("Preprocessor Error", maybe_source.error()!).format(formatter))
+        return
+      }
+
+      let maybe_program = Program.Compile(source.getSource())
+      guard case .Ok(let program) = maybe_program else {
+        print(ErrorWithLabel("Compiler Error", maybe_source.error()!).format(formatter))
+        return
+      }
+
+      let maybe_codegen = P4Runtime.CodeGenerator().codeGen(program)
+      guard case .Ok(let codegen) = maybe_codegen else {
+        let formatter = FormatterAnsi()
+        print(ErrorWithLabel("Code Generation Error", maybe_codegen.error()!).format(formatter))
+        return
+      }
+
+      print("\(codegen.getGeneratedCode())")
+    }
+  }
+}