Implement AST serialization.

src/main/kotlin/gay/pizza/pork/cli/AstCommand.kt

@@ -0,0 +1,31 @@
+package gay.pizza.pork.cli
+
+import com.github.ajalt.clikt.core.CliktCommand
+import com.github.ajalt.clikt.parameters.arguments.argument
+import com.github.ajalt.clikt.parameters.types.path
+import gay.pizza.pork.ast.nodes.Node
+import gay.pizza.pork.parse.PorkParser
+import gay.pizza.pork.parse.PorkTokenizer
+import gay.pizza.pork.parse.StringCharSource
+import gay.pizza.pork.parse.TokenStreamSource
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.json.Json
+import kotlin.io.path.readText
+
+@OptIn(ExperimentalSerializationApi::class)
+class AstCommand : CliktCommand(help = "Print AST", name = "ast") {
+  val path by argument("file").path(mustExist = true, canBeDir = false)
+
+  private val json = Json {
+    prettyPrint = true
+    prettyPrintIndent = "  "
+    classDiscriminator = "\$"
+  }
+
+  override fun run() {
+    val content = path.readText()
+    val tokenStream = PorkTokenizer(StringCharSource(content)).tokenize()
+    val program = PorkParser(TokenStreamSource(tokenStream)).readProgram()
+    println(json.encodeToString(Node.serializer(), program))
+  }
+}

src/main/kotlin/gay/pizza/pork/cli/RootCommand.kt

@@ -13,6 +13,7 @@ class RootCommand : CliktCommand(
       HighlightCommand(),
       TokenizeCommand(),
       ReprintCommand(),
+      AstCommand(),
       GenerateKotlinCommand()
     )
   }