Add parsing for defers

ppp_ast.py

@@ -543,3 +543,7 @@ class Import(Statement):
 class TypeDefinition(Statement):
 	name: str
 	expression: TypeExpression
+
+@dataclass
+class DeferStatement(Statement):
+        statement: Statement

ppp_interpreter.py

@@ -656,6 +656,8 @@ def interpret_statements(statements: List_[Statement], program: ProgramState) ->
 					program.modules[file.str] = module
 			case TypeDefinition(name, expression_):
 				program.declare_and_assign_variable(name, TypeObject(calculate_type_expression(expression_, program)))
+			case DeferStatement(statement=statement):
+				assert False, "TODO: Defers are not implemented"
 			case _:
 				assert False, ("Unimplemented", statement)
 	return NothingResult()

ppp_parser.py

@@ -358,6 +358,9 @@ def parse_statement(lexer: Lexer) -> Statement:
 		type_expression = parse_type(lexer)
 		lexer.assert_token(SymbolToken(Symbol.Semicolon))
 		return TypeDefinition(name, type_expression)
+	elif lexer.take_token(KeywordToken(Keyword.Defer)):
+		statement = parse_statement(lexer)
+		return DeferStatement(statement)
 	elif lexer.check_tokenkind(KeywordToken) and not lexer.check_tokens(KeywordToken(Keyword.Return), KeywordToken(Keyword.Lambda)):
 		assert False, ("Unimplemented", lexer.next_token(), lexer.next_token(), lexer.next_token())
 	elif lexer.take_token(SymbolToken(Symbol.OpenCurly)):

ppp_tokens.py

@@ -23,6 +23,7 @@ class Keyword(Enum):
 	Lambda = 'lambda'
 	Import = 'import'
 	Type = 'type'
+	Defer = 'defer'
 
 class Symbol(Enum):
 	Open = '('