1 files changed, 145 insertions, 0 deletions
diff --git a/nodes.py b/nodes.py
new file mode 100644
index 0000000..1721049
--- /dev/null
+++ b/nodes.py
@@ -0,0 +1,145 @@
+# coding: utf-8
+
+import sys
+
+from typing import Dict, Any, Text, Optional  # NOQA
+from ruamel.yaml.tag import Tag
+
+
+class Node:
+    __slots__ = 'ctag', 'value', 'start_mark', 'end_mark', 'comment', 'anchor'
+
+    def __init__(
+        self,
+        tag: Any,
+        value: Any,
+        start_mark: Any,
+        end_mark: Any,
+        comment: Any = None,
+        anchor: Any = None,
+    ) -> None:
+        # you can still get a string from the serializer
+        self.ctag = tag if isinstance(tag, Tag) else Tag(suffix=tag)
+        self.value = value
+        self.start_mark = start_mark
+        self.end_mark = end_mark
+        self.comment = comment
+        self.anchor = anchor
+
+    @property
+    def tag(self) -> Optional[str]:
+        return None if self.ctag is None else str(self.ctag)
+
+    @tag.setter
+    def tag(self, val: Any) -> None:
+        if isinstance(val, str):
+            val = Tag(suffix=val)
+        self.ctag = val
+
+    def __repr__(self) -> Any:
+        value = self.value
+        # if isinstance(value, list):
+        #     if len(value) == 0:
+        #         value = '<empty>'
+        #     elif len(value) == 1:
+        #         value = '<1 item>'
+        #     else:
+        #         value = f'<{len(value)} items>'
+        # else:
+        #     if len(value) > 75:
+        #         value = repr(value[:70]+' ... ')
+        #     else:
+        #         value = repr(value)
+        value = repr(value)
+        return f'{self.__class__.__name__!s}(tag={self.tag!r}, value={value!s})'
+
+    def dump(self, indent: int = 0) -> None:
+        xx = self.__class__.__name__
+        xi = '  ' * indent
+        if isinstance(self.value, str):
+            sys.stdout.write(f'{xi}{xx}(tag={self.tag!r}, value={self.value!r})\n')
+            if self.comment:
+                sys.stdout.write(f'    {xi}comment: {self.comment})\n')
+            return
+        sys.stdout.write(f'{xi}{xx}(tag={self.tag!r})\n')
+        if self.comment:
+            sys.stdout.write(f'    {xi}comment: {self.comment})\n')
+        for v in self.value:
+            if isinstance(v, tuple):
+                for v1 in v:
+                    v1.dump(indent + 1)
+            elif isinstance(v, Node):
+                v.dump(indent + 1)
+            else:
+                sys.stdout.write(f'Node value type? {type(v)}\n')
+
+
+class ScalarNode(Node):
+    """
+    styles:
+      ? -> set() ? key, no value
+      - -> suppressable null value in set
+      " -> double quoted
+      ' -> single quoted
+      | -> literal style
+      > -> folding style
+    """
+
+    __slots__ = ('style',)
+    id = 'scalar'
+
+    def __init__(
+        self,
+        tag: Any,
+        value: Any,
+        start_mark: Any = None,
+        end_mark: Any = None,
+        style: Any = None,
+        comment: Any = None,
+        anchor: Any = None,
+    ) -> None:
+        Node.__init__(self, tag, value, start_mark, end_mark, comment=comment, anchor=anchor)
+        self.style = style
+
+
+class CollectionNode(Node):
+    __slots__ = ('flow_style',)
+
+    def __init__(
+        self,
+        tag: Any,
+        value: Any,
+        start_mark: Any = None,
+        end_mark: Any = None,
+        flow_style: Any = None,
+        comment: Any = None,
+        anchor: Any = None,
+    ) -> None:
+        Node.__init__(self, tag, value, start_mark, end_mark, comment=comment)
+        self.flow_style = flow_style
+        self.anchor = anchor
+
+
+class SequenceNode(CollectionNode):
+    __slots__ = ()
+    id = 'sequence'
+
+
+class MappingNode(CollectionNode):
+    __slots__ = ('merge',)
+    id = 'mapping'
+
+    def __init__(
+        self,
+        tag: Any,
+        value: Any,
+        start_mark: Any = None,
+        end_mark: Any = None,
+        flow_style: Any = None,
+        comment: Any = None,
+        anchor: Any = None,
+    ) -> None:
+        CollectionNode.__init__(
+            self, tag, value, start_mark, end_mark, flow_style, comment, anchor,
+        )
+        self.merge = None