diff --git a/il65/plyparser.py b/il65/plyparser.py
index 378c7980a..3aa99a529 100644
--- a/il65/plyparser.py
+++ b/il65/plyparser.py
@@ -6,7 +6,7 @@ Written by Irmen de Jong (irmen@razorvine.net)
 License: GNU GPL 3.0, see LICENSE
 """
 
-from typing import List, Any
+from typing import List, Set
 from ply.yacc import yacc
 from .symbols import SourceRef, AstNode
 from .lexer import tokens, lexer, find_tok_column   # get the lexer tokens. required.
@@ -89,10 +89,13 @@ class Return(AstNode):
 
 
 class TargetRegisters(AstNode):
-    def __init__(self, registers, sourceref: SourceRef) -> None:
+    def __init__(self, registers: List[str], sourceref: SourceRef) -> None:
         super().__init__(sourceref)
         self.registers = registers
 
+    def add_register(self, register) -> None:
+        self.registers.append(register)
+
 
 class InlineAssembly(AstNode):
     def __init__(self, assembly: str, sourceref: SourceRef) -> None:
@@ -754,5 +757,5 @@ if __name__ == "__main__":
     tokenfilter = TokenFilter(lexer)
     result = parser.parse(input=file.read(),
                           tokenfunc=tokenfilter.token) or Module(None, SourceRef(lexer.source_filename, 1, 1))
-    # print("RESULT:")
-    # print(str(result))
+    print("RESULT:")
+    result.print_tree()
diff --git a/il65/symbols.py b/il65/symbols.py
index 16fa146f9..c02df38a2 100644
--- a/il65/symbols.py
+++ b/il65/symbols.py
@@ -700,37 +700,28 @@ class AstNode:
     def lineref(self) -> str:
         return "src l. " + str(self.sourceref.line)
 
-    def __str__(self) -> str:
-        def tostr(node: Any, level: int) -> str:
-            indent = "   "
-            clsname = node.__class__.__name__
-            attrs = []
+    def print_tree(self) -> None:
+        def tostr(node: AstNode, level: int) -> None:
+            if not isinstance(node, AstNode):
+                return
+            indent = "   " * level
+            name = getattr(node, "name", "")
+            print(indent, node.__class__.__name__, repr(name))
             try:
-                nvars = vars(node)
+                variables = vars(node).items()
             except TypeError:
-                if type(node) is str:
-                    sv = repr(node)
-                    if len(sv) > 20:
-                        sv = sv[:20] + "...'"
-                    return sv
-                return str(node)
-            for name, value in nvars.items():
-                if name == "sourceref":
-                    continue
-                elif type(value) in (str, int, float, bool, type(None)):
-                    attrs.append((name, tostr(value, level+1)))
-                elif type(value) is list:
-                    strvalue = "["
-                    strvalue += (",\n" + indent*(level+1)).join(tostr(v, level+1) for v in value) + "\n" + (1+level)*indent + "]"
-                    attrs.append((name, strvalue))
-                elif type(value) is not list and type(value) not in (str, int, float, bool, type(None)):
-                    attrs.append((name, tostr(value, level+2)))
-                else:
-                    raise TypeError("WEIRD TYPE", type(value))
-            attrstr = ("\n" + indent*(1+level)).join("{} = {}".format(name, sv) for name, sv in attrs)
-            result = "\n" + indent * level + "<{0:s}  l={1:d}  c={2:d}".format(clsname, node.sourceref.line, node.sourceref.column)
-            return result + "{} |end {} l={:d}|>".format(attrstr, clsname, node.sourceref.line)
-        return tostr(self, 0)
+                variables = {}
+            for name, value in variables:
+                if isinstance(value, AstNode):
+                    tostr(value, level + 1)
+                if isinstance(value, (list, tuple, set)):
+                    if len(value) > 0:
+                        elt = list(value)[0]
+                        if isinstance(elt, AstNode) or name == "nodes":
+                            print(indent, "  >", name, "=")
+                            for elt in value:
+                                tostr(elt, level + 2)
+        tostr(self, 0)
 
 
 class Block(AstNode):
diff --git a/todo.ill b/todo.ill
index c6da268b1..1f43b7410 100644
--- a/todo.ill
+++ b/todo.ill
@@ -2,7 +2,7 @@
 %import c64lib
 %import mathlib
 
-~ main {
+~ main $4444 {
 
 
                 const   num = 2