more work on plasma parser

AST.py

@@ -0,0 +1,44 @@
+from abc import ABC, abstractmethod
+from enum import Enum
+
+
+class NodeType(Enum):
+    Program = "Program"
+
+    # Statements
+    ExpressionStatement = "ExpressionStatement"
+
+    # Expressions
+    InfixExpression = "InfixExpression"
+
+    # Literals
+    IntegerLiteral = "IntegerLiteral"
+    FloatLiteral = "FloatLiteral"
+
+class Node:
+    @abstractmethod
+    def type(self) -> NodeType:
+        pass
+
+    @abstractmethod
+    def json(self) -> dict:
+        pass
+
+class Statement(Node):
+    pass
+
+class Expression(Node):
+    pass
+
+class Program(Node):
+    def __init__(self) -> None:
+        self.statements: list[Statement] = []
+
+    def type(self) -> NodeType:
+        return NodeType.Program
+    
+    def json(self) -> dict:
+        return {
+            "type": self.type().value,
+            "statements": []
+        }