adds Symbol.py core_developer_branch
authorThomas Walker Lynch <eknp9n@reasoningtechnology.com>
Fri, 16 Jan 2026 11:45:20 +0000 (11:45 +0000)
committerThomas Walker Lynch <eknp9n@reasoningtechnology.com>
Fri, 16 Jan 2026 11:45:20 +0000 (11:45 +0000)
18 files changed:
developer/authored/ObjectRegistry.py [deleted file]
developer/authored/ProcessLocalId.py [deleted file]
developer/authored/Property.py [deleted file]
developer/authored/PropertyManager.py [deleted file]
developer/authored/PropertyStore.py [deleted file]
developer/authored/SemanticSets.py [deleted file]
developer/authored/Symbol.py [new file with mode: 0644]
developer/authored/Syntax.py [deleted file]
developer/authored/__init__.py
developer/authored/deprecated/ObjectRegistry.py [new file with mode: 0644]
developer/authored/deprecated/ProcessLocalId.py [new file with mode: 0644]
developer/authored/deprecated/Property.py [new file with mode: 0644]
developer/authored/deprecated/PropertyManager.py [new file with mode: 0644]
developer/authored/deprecated/PropertyStore.py [new file with mode: 0644]
developer/authored/deprecated/SemanticSets.py [new file with mode: 0644]
developer/authored/deprecated/Syntax.py [new file with mode: 0644]
developer/authored/test_SymbolFactory.py [new file with mode: 0755]
document/Epimetheus.html

diff --git a/developer/authored/ObjectRegistry.py b/developer/authored/ObjectRegistry.py
deleted file mode 100644 (file)
index 9d30fd9..0000000
+++ /dev/null
@@ -1,113 +0,0 @@
-#!/usr/bin/env python3
-# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
-
-"""
-ObjectRegistry
-
-Maps Python runtime objects to ProcessLocalId.
-
-Strategies:
-  1. Weak Identity (Preferred): For objects that support weakrefs (instances ,classes).
-     - ID lifetime is bound to object lifetime.
-     - Auto-cleaned on GC.
-  
-  2. Value Identity (Fallback): For immutable primitives (int ,str ,tuple).
-     - ID is bound to the *value* (hash/equality).
-     - Stored strongly (since values like 42 or "red" are conceptually eternal).
-"""
-
-from __future__ import annotations
-
-import weakref
-from typing import Any ,Callable ,Dict ,Optional
-
-from .ProcessLocalId import ProcessLocalIdGenerator ,ProcessLocalId
-
-
-class ObjectRegistry:
-  def __init__(self ,id_gen: ProcessLocalIdGenerator):
-    self._id_gen = id_gen
-    
-    # Strategy 1: Entities (Weakref-able)
-    self._obj_to_id_wkd: "weakref.WeakKeyDictionary[Any ,ProcessLocalId]" = weakref.WeakKeyDictionary()
-    self._id_to_obj_ref: Dict[ProcessLocalId ,weakref.ref] = {}
-    
-    # Strategy 2: Values (Hashable ,not weakref-able)
-    self._value_to_id: Dict[Any ,ProcessLocalId] = {}
-    
-    self._finalizers: Dict[ProcessLocalId ,Callable[[ProcessLocalId] ,None]] = {}
-    self._global_finalizer: Optional[Callable[[ProcessLocalId] ,None]] = None
-
-  def register_finalizer(self ,fn: Callable[[ProcessLocalId] ,None]):
-    """
-    Registers a finalizer callback invoked when any registered *weak-refable* object is GC'd.
-    """
-    self._global_finalizer = fn
-
-  def _on_collect(self ,obj_id: ProcessLocalId):
-    # Only called for Strategy 1 objects
-    ref = self._id_to_obj_ref.pop(obj_id ,None)
-    if(ref is not None):
-      # The WeakKeyDictionary auto-cleans the forward mapping ,
-      # but we double check or clean any edge cases if needed.
-      pass 
-      
-    fn = self._global_finalizer
-    if(fn is not None):
-      fn(obj_id)
-
-  def get_id(self ,obj: Any) -> ProcessLocalId:
-    """
-    Returns the ProcessLocalId for `obj` ,registering it if needed.
-    """
-    # 1. Try WeakRef Strategy (Entities)
-    try:
-      existing = self._obj_to_id_wkd.get(obj)
-      if(existing is not None):
-        return existing
-    except TypeError:
-      # obj is not weakref-able (e.g. int ,str ,tuple ,or list).
-      # Fall through to Strategy 2.
-      pass
-    else:
-      # It IS weakref-able ,but wasn't in the dictionary. Register it.
-      obj_id = self._id_gen.next_id()
-      self._obj_to_id_wkd[obj] = obj_id
-      # Create reverse lookup with callback
-      self._id_to_obj_ref[obj_id] = weakref.ref(obj ,lambda _ref ,oid=obj_id: self._on_collect(oid))
-      return obj_id
-
-    # 2. Try Value Strategy (Primitives)
-    # Note: Mutable non-weakrefables (like standard lists) will fail here because they are unhashable.
-    try:
-      existing = self._value_to_id.get(obj)
-      if(existing is not None):
-        return existing
-      
-      # Register new value
-      obj_id = self._id_gen.next_id()
-      self._value_to_id[obj] = obj_id
-      return obj_id
-    except TypeError:
-      # It is neither weakref-able NOR hashable (e.g. standard list ,dict).
-      raise TypeError(
-        f"ObjectRegistry: cannot track object of type {type(obj)!r}. "
-        "It is neither weakref-able (Entity) nor hashable (Value)."
-      )
-
-  def try_get_object(self ,obj_id: ProcessLocalId) -> Optional[Any]:
-    """
-    Best-effort: returns the live object/value.
-    """
-    # Check Entities
-    ref = self._id_to_obj_ref.get(obj_id)
-    if(ref is not None):
-      return ref()
-      
-    # Check Values
-    # For now ,we assume values identify themselves.
-    for val ,pid in self._value_to_id.items():
-      if(pid == obj_id):
-        return val
-        
-    return None
diff --git a/developer/authored/ProcessLocalId.py b/developer/authored/ProcessLocalId.py
deleted file mode 100644 (file)
index b57c47c..0000000
+++ /dev/null
@@ -1,52 +0,0 @@
-#!/usr/bin/env python3
-# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
-
-
-"""
-ProcessLocalId
-
-A process-local identifier used as an internal key.
-
-Design constraint:
-  - NOT intended to be serialized or persisted.
-  - `repr()` intentionally does not reveal the numeric token, to discourage logging/persistence.
-"""
-
-from __future__ import annotations
-
-from dataclasses import dataclass
-
-
-@dataclass(frozen=True ,slots=True)
-class ProcessLocalId:
-  _n: int
-
-  def __repr__(self) -> str:
-    return "<ProcessLocalId>"
-
-  def __str__(self) -> str:
-    return "<ProcessLocalId>"
-
-  def as_int_UNSAFE(self) -> int:
-    """
-    Returns the raw integer token.
-
-    UNSAFE because:
-      - tokens are process-local
-      - do not write these into files/databases/logs as stable identifiers
-    """
-    return self._n
-
-
-class ProcessLocalIdGenerator:
-  """
-  Monotonic generator; ids are never recycled.
-  """
-  def __init__(self ,start: int = 1):
-    if start < 1: raise ValueError("start must be >= 1")
-    self._next_n: int = start
-
-  def next_id(self) -> ProcessLocalId:
-    n = self._next_n
-    self._next_n += 1
-    return ProcessLocalId(n)
diff --git a/developer/authored/Property.py b/developer/authored/Property.py
deleted file mode 100644 (file)
index 5b33226..0000000
+++ /dev/null
@@ -1,29 +0,0 @@
-#!/usr/bin/env python3
-# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
-
-
-"""
-Property
-
-A Property is itself an entity (it has an Identity id) so that:
-  - properties can have properties
-  - properties can be members of semantic sets
-"""
-
-from __future__ import annotations
-
-from dataclasses import dataclass
-from typing import Optional ,Tuple
-
-from .ProcessLocalId import ProcessLocalId
-
-
-@dataclass(frozen=True ,slots=True)
-class Property:
-  id: ProcessLocalId
-  name_path: Tuple[str ,...]
-  doc: str = ""
-
-  def __repr__(self) -> str:
-    # name_path is safe to reveal; id token is not.
-    return f"<Property {'.'.join(self.name_path)!r}>"
diff --git a/developer/authored/PropertyManager.py b/developer/authored/PropertyManager.py
deleted file mode 100644 (file)
index 36e2b9e..0000000
+++ /dev/null
@@ -1,155 +0,0 @@
-#!/usr/bin/env python3
-# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
-
-
-"""
-PropertyManager
-
-Core RT property system.
-
-Key decisions vs the earlier `property_manager.py`:
-  - do NOT key by `object_path()` strings (avoids collisions) fileciteturn3file4
-  - runtime objects are keyed by weak identity (ProcessLocalId assigned by ObjectRegistry)
-  - properties are first-class entities (Property has an id), so properties can have properties
-
-This remains process-local and in-memory.
-"""
-
-from __future__ import annotations
-
-from typing import Any ,Dict ,Iterable ,List ,Optional ,Tuple ,Union
-
-from .ProcessLocalId import ProcessLocalIdGenerator ,ProcessLocalId
-from .ObjectRegistry import ObjectRegistry
-from .PropertyStore import PropertyStore
-from .Property import Property
-from .SemanticSets import SemanticSet ,SemanticSetStore
-from .Syntax import SyntaxInstance
-
-
-NamePathLike = Union[str ,List[str] ,Tuple[str ,...]]
-
-
-class PropertyManager:
-  def __init__(self):
-    self._id_gen = ProcessLocalIdGenerator()
-    self._obj_reg = ObjectRegistry(self._id_gen)
-    self._store = PropertyStore()
-    self._sets = SemanticSetStore()
-
-    # Declare-by-name registry
-    self._name_path_to_property: Dict[Tuple[str ,...],Property] = {}
-    self._property_id_to_property: Dict[ProcessLocalId ,Property] = {}
-
-    self._name_path_to_set: Dict[Tuple[str ,...],SemanticSet] = {}
-    self._set_id_to_set: Dict[ProcessLocalId ,SemanticSet] = {}
-
-    # Optional syntax instances (if user chooses to model them)
-    self._syntax_id_to_instance: Dict[ProcessLocalId ,SyntaxInstance] = {}
-
-    # Finalization cleanup
-    self._obj_reg.register_finalizer(self._on_subject_finalized)
-
-  def _on_subject_finalized(self ,subject_id: ProcessLocalId):
-    self._store.remove_subject(subject_id)
-    self._sets.remove_subject(subject_id)
-
-  def _normalize_name_path(self ,name_path: NamePathLike) -> Tuple[str ,...]:
-    if isinstance(name_path ,tuple): return name_path
-    if isinstance(name_path ,list): return tuple(name_path)
-    if isinstance(name_path ,str): return tuple(name_path.split("."))
-    raise TypeError("name_path must be str ,list[str] ,or tuple[str ,...]")
-
-  # -------------------------
-  # Identity acquisition
-  # -------------------------
-  def id_of_py_object(self ,obj: Any) -> ProcessLocalId:
-    return self._obj_reg.get_id(obj)
-
-  def create_syntax_identity(self ,syntax: SyntaxInstance) -> ProcessLocalId:
-    sid = self._id_gen.next_id()
-    self._syntax_id_to_instance[sid] = syntax
-    return sid
-
-  def try_get_syntax(self ,syntax_id: ProcessLocalId) -> Optional[SyntaxInstance]:
-    return self._syntax_id_to_instance.get(syntax_id)
-
-  # -------------------------
-  # Property declaration
-  # -------------------------
-  def declare_property(self ,name_path: NamePathLike ,doc: str = "") -> ProcessLocalId:
-    np = self._normalize_name_path(name_path)
-    existing = self._name_path_to_property.get(np)
-    if existing is not None: return existing.id
-    pid = self._id_gen.next_id()
-    p = Property(pid ,np ,doc)
-    self._name_path_to_property[np] = p
-    self._property_id_to_property[pid] = p
-    return pid
-
-  def property_id(self ,name_path: NamePathLike) -> ProcessLocalId:
-    np = self._normalize_name_path(name_path)
-    p = self._name_path_to_property.get(np)
-    if p is None: raise KeyError(f"Property not declared: {np!r}")
-    return p.id
-
-  def try_get_property(self ,prop_id: ProcessLocalId) -> Optional[Property]:
-    return self._property_id_to_property.get(prop_id)
-
-  # -------------------------
-  # Semantic sets
-  # -------------------------
-  def declare_set(self ,name_path: NamePathLike ,doc: str = "") -> ProcessLocalId:
-    np = self._normalize_name_path(name_path)
-    existing = self._name_path_to_set.get(np)
-    if existing is not None: return existing.id
-    sid = self._id_gen.next_id()
-    s = SemanticSet(sid ,np ,doc)
-    self._name_path_to_set[np] = s
-    self._set_id_to_set[sid] = s
-    return sid
-
-  def add_to_set(self ,subject: Any ,set_id: ProcessLocalId):
-    subject_id = self._coerce_subject_id(subject)
-    self._sets.add_member(set_id ,subject_id)
-
-  def is_in_set(self ,subject: Any ,set_id: ProcessLocalId) -> bool:
-    subject_id = self._coerce_subject_id(subject)
-    return self._sets.has_member(set_id ,subject_id)
-
-  def members(self ,set_id: ProcessLocalId) -> List[ProcessLocalId]:
-    return list(self._sets.members(set_id))
-
-  # -------------------------
-  # Set/get properties
-  # -------------------------
-  def set(self ,subject: Any ,prop: Union[ProcessLocalId ,NamePathLike] ,value: Any):
-    subject_id = self._coerce_subject_id(subject)
-    prop_id = self._coerce_property_id(prop)
-    self._store.set(subject_id ,prop_id ,value)
-
-  def get(self ,subject: Any ,prop: Union[ProcessLocalId ,NamePathLike] ,default: Any = None) -> Any:
-    subject_id = self._coerce_subject_id(subject)
-    prop_id = self._coerce_property_id(prop)
-    return self._store.get(subject_id ,prop_id ,default)
-
-  def has(self ,subject: Any ,prop: Union[ProcessLocalId ,NamePathLike]) -> bool:
-    subject_id = self._coerce_subject_id(subject)
-    prop_id = self._coerce_property_id(prop)
-    return self._store.has(subject_id ,prop_id)
-
-  def subjects_with(self ,prop: Union[ProcessLocalId ,NamePathLike]) -> List[ProcessLocalId]:
-    prop_id = self._coerce_property_id(prop)
-    return list(self._store.subjects_with(prop_id))
-
-  # -------------------------
-  # Coercions
-  # -------------------------
-  def _coerce_subject_id(self ,subject: Any) -> ProcessLocalId:
-    if isinstance(subject ,ProcessLocalId): return subject
-    # For Python runtime objects, we require weakref-able instances.
-    return self._obj_reg.get_id(subject)
-
-  def _coerce_property_id(self ,prop: Union[ProcessLocalId ,NamePathLike]) -> ProcessLocalId:
-    if isinstance(prop ,ProcessLocalId): return prop
-    return self.property_id(prop)
diff --git a/developer/authored/PropertyStore.py b/developer/authored/PropertyStore.py
deleted file mode 100644 (file)
index bc8f3f3..0000000
+++ /dev/null
@@ -1,59 +0,0 @@
-#!/usr/bin/env python3
-# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
-
-
-"""
-PropertyStore
-
-Stores property values and maintains reverse lookups.
-
-This is intentionally process-local and in-memory.
-"""
-
-from __future__ import annotations
-
-from typing import Any ,Dict ,Optional ,Set ,Tuple
-
-from .ProcessLocalId import ProcessLocalId
-
-
-class PropertyStore:
-  def __init__(self):
-    # (subject_id ,property_id) -> value
-    self._values: Dict[Tuple[ProcessLocalId ,ProcessLocalId] ,Any] = {}
-
-    # subject_id -> set(property_id)
-    self._subject_to_props: Dict[ProcessLocalId ,Set[ProcessLocalId]] = {}
-
-    # property_id -> set(subject_id)
-    self._prop_to_subjects: Dict[ProcessLocalId ,Set[ProcessLocalId]] = {}
-
-  def set(self ,subject_id: ProcessLocalId ,prop_id: ProcessLocalId ,value: Any):
-    key = (subject_id ,prop_id)
-    self._values[key] = value
-    self._subject_to_props.setdefault(subject_id ,set()).add(prop_id)
-    self._prop_to_subjects.setdefault(prop_id ,set()).add(subject_id)
-
-  def get(self ,subject_id: ProcessLocalId ,prop_id: ProcessLocalId ,default: Any = None) -> Any:
-    return self._values.get((subject_id ,prop_id) ,default)
-
-  def has(self ,subject_id: ProcessLocalId ,prop_id: ProcessLocalId) -> bool:
-    return (subject_id ,prop_id) in self._values
-
-  def subjects_with(self ,prop_id: ProcessLocalId) -> Set[ProcessLocalId]:
-    return set(self._prop_to_subjects.get(prop_id ,set()))
-
-  def props_of(self ,subject_id: ProcessLocalId) -> Set[ProcessLocalId]:
-    return set(self._subject_to_props.get(subject_id ,set()))
-
-  def remove_subject(self ,subject_id: ProcessLocalId):
-    """
-    Remove all stored properties for a subject (used on finalization).
-    """
-    prop_ids = self._subject_to_props.pop(subject_id ,set())
-    for prop_id in prop_ids:
-      self._values.pop((subject_id ,prop_id) ,None)
-      s = self._prop_to_subjects.get(prop_id)
-      if s is not None:
-        s.discard(subject_id)
-        if not s: self._prop_to_subjects.pop(prop_id ,None)
diff --git a/developer/authored/SemanticSets.py b/developer/authored/SemanticSets.py
deleted file mode 100644 (file)
index f0fdf48..0000000
+++ /dev/null
@@ -1,55 +0,0 @@
-#!/usr/bin/env python3
-# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
-
-
-"""
-SemanticSets
-
-Membership sets over identities. Used for semantic typing.
-
-Design:
-  - set_id identifies the set
-  - members are subject ids
-  - reverse index for cleanup
-"""
-
-from __future__ import annotations
-
-from dataclasses import dataclass
-from typing import Dict ,Optional ,Set
-
-from .ProcessLocalId import ProcessLocalId
-
-
-@dataclass(frozen=True ,slots=True)
-class SemanticSet:
-  id: ProcessLocalId
-  name_path: tuple[str ,...]
-  doc: str = ""
-
-  def __repr__(self) -> str:
-    return f"<SemanticSet {'.'.join(self.name_path)!r}>"
-
-
-class SemanticSetStore:
-  def __init__(self):
-    self._members: Dict[ProcessLocalId ,Set[ProcessLocalId]] = {}
-    self._subject_to_sets: Dict[ProcessLocalId ,Set[ProcessLocalId]] = {}
-
-  def add_member(self ,set_id: ProcessLocalId ,subject_id: ProcessLocalId):
-    self._members.setdefault(set_id ,set()).add(subject_id)
-    self._subject_to_sets.setdefault(subject_id ,set()).add(set_id)
-
-  def has_member(self ,set_id: ProcessLocalId ,subject_id: ProcessLocalId) -> bool:
-    return subject_id in self._members.get(set_id ,set())
-
-  def members(self ,set_id: ProcessLocalId) -> Set[ProcessLocalId]:
-    return set(self._members.get(set_id ,set()))
-
-  def remove_subject(self ,subject_id: ProcessLocalId):
-    set_ids = self._subject_to_sets.pop(subject_id ,set())
-    for set_id in set_ids:
-      m = self._members.get(set_id)
-      if m is not None:
-        m.discard(subject_id)
-        if not m: self._members.pop(set_id ,None)
diff --git a/developer/authored/Symbol.py b/developer/authored/Symbol.py
new file mode 100644 (file)
index 0000000..1240480
--- /dev/null
@@ -0,0 +1,153 @@
+#!/usr/bin/env python3
+# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
+
+"""
+Symbol
+
+The Definition of Identity.
+
+Architecture:
+  - Symbol: The namespace and manager (Factory).
+  - Symbol.Instance: The atomic unit of identity (The Product).
+
+Constraints:
+  - Distinctness: Instances are unique.
+  - Opaque: No internal state leakage.
+  - Immutable Metadata: Name and Doc can be set exactly once.
+  - Static Manager: The Symbol class cannot be instantiated.
+"""
+
+from __future__ import annotations
+
+import weakref
+from typing import Optional
+
+
+class Symbol:
+  """
+  The Manager class.
+  Maintains the global state for symbol metadata and token generation.
+  """
+
+  def __new__(cls):
+    """
+    Prevent instantiation. Symbol is a static namespace/factory.
+    """
+    raise TypeError("The Symbol class is a static namespace and cannot be instantiated.")
+
+  # Global registry for metadata.
+  # We use class-level storage so Instances remain lightweight (no back-ref needed).
+  _names: weakref.WeakKeyDictionary[Symbol.Instance ,str] = weakref.WeakKeyDictionary()
+  _docs: weakref.WeakKeyDictionary[Symbol.Instance ,str] = weakref.WeakKeyDictionary()
+
+  # Inclusive bounding: Start at 0 (The Null Token)
+  _current_token: int = 0
+
+  class Instance:
+    """
+    The atomic unit of identity.
+    """
+    # __weakref__ required for WeakKeyDictionary keys
+    __slots__ = (
+      '_token'
+      ,'__weakref__'
+    )
+
+    def __init__(self ,token: int):
+      self._token = token
+
+    def __repr__(self) -> str:
+      return "<Symbol.Instance>"
+
+    def __eq__(self ,other: object) -> bool:
+      if( isinstance(other ,Symbol.Instance) ):
+        return self._token == other._token
+      return NotImplemented
+
+    def __hash__(self) -> int:
+      return hash(self._token)
+
+    # ----------------------------------------------------------------------
+    # Metadata Accessors
+    # ----------------------------------------------------------------------
+
+    @property
+    def name(self) -> Optional[str]:
+      """
+      Returns the name of the symbol, or None if anonymous.
+      """
+      return Symbol._names.get(self)
+
+    @name.setter
+    def name(self ,value: str):
+      """
+      Sets the name.
+      Raises RuntimeError if the name has already been set.
+      """
+      if( self in Symbol._names ):
+        raise RuntimeError(f"Symbol name is immutable. Already set to '{Symbol._names[self]}'.")
+      Symbol._names[self] = value
+
+    @property
+    def doc(self) -> str:
+      """
+      Returns the docstring of the symbol, or "" if none.
+      """
+      return Symbol._docs.get(self ,"")
+
+    @doc.setter
+    def doc(self ,value: str):
+      """
+      Sets the docstring.
+      Raises RuntimeError if the docstring has already been set.
+      Ignores empty strings (setting to "" is a no-op).
+      """
+      if( not value ): return
+
+      if( self in Symbol._docs ):
+        raise RuntimeError("Symbol docstring is immutable. Already set.")
+
+      Symbol._docs[self] = value
+
+  # ------------------------------------------------------------------------
+  # Factory Methods
+  # ------------------------------------------------------------------------
+
+  @classmethod
+  def make(cls ,name: Optional[str] = None ,doc: str = "") -> Instance:
+    """
+    Mints a new, distinct Original Symbol Instance.
+
+    Args:
+      name: Optional name. If provided, it becomes immutable.
+      doc: Optional docstring. If provided (non-empty), it becomes immutable.
+    """
+    # The Rest: Increment first, so the first public symbol is 1.
+    cls._current_token += 1
+    token = cls._current_token
+
+    instance = cls.Instance(token)
+
+    if( name is not None ):
+      # Direct injection to bypass the "check if set" logic of the setter
+      cls._names[instance] = name
+
+    if( doc ):
+      cls._docs[instance] = doc
+
+    return instance
+
+  # ------------------------------------------------------------------------
+  # Static Initialization (The First)
+  # ------------------------------------------------------------------------
+  # We perform this inside the class body using local names.
+  # This creates the Null Symbol immediately upon class definition.
+
+  # Note: We must use 'Instance' (local scope) not 'Symbol.Instance'
+  # because 'Symbol' is not yet bound.
+  null = Instance(0)
+  _names[null] = "Null"
+  _docs[null] = "The Null Symbol"
+  
+
+#  LocalWords:  Accessors
diff --git a/developer/authored/Syntax.py b/developer/authored/Syntax.py
deleted file mode 100644 (file)
index 4fcfa7c..0000000
+++ /dev/null
@@ -1,59 +0,0 @@
-#!/usr/bin/env python3
-# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
-
-
-"""
-Syntax
-
-RT syntax identity instances.
-
-We treat "syntax" as AST-level objects:
-  - kind: official-ish AST node kind name (e.g., "ast.FunctionDef")
-  - location: file + span
-  - scope: enclosing syntax identity id (optional)
-  - parts: mapping of part-name to literal or referenced syntax identity id(s)
-
-This module does NOT traverse Python programs. It only defines the data model.
-"""
-
-from __future__ import annotations
-
-from dataclasses import dataclass
-from typing import Any ,Dict ,Optional ,Tuple ,Union ,List
-
-from .ProcessLocalId import ProcessLocalId
-
-
-@dataclass(frozen=True ,slots=True)
-class SourceSpan:
-  file_path: str
-  lineno: int
-  col: int
-  end_lineno: int
-  end_col: int
-
-
-SyntaxPartValue = Union[
-  None
-  ,bool
-  ,int
-  ,float
-  ,str
-  ,ProcessLocalId
-  ,List["SyntaxPartValue"]
-  ,Dict[str ,"SyntaxPartValue"]
-]
-
-
-@dataclass(frozen=True ,slots=True)
-class SyntaxInstance:
-  """
-  A single syntax node instance.
-
-  NOTE: many syntax nodes have no identifier-name. Name-like things (identifiers)
-  appear as child nodes or literals inside `parts`.
-  """
-  kind: str
-  span: SourceSpan
-  scope_id: Optional[ProcessLocalId] = None
-  parts: Dict[str ,SyntaxPartValue] = None
index ce046ae..dce65e6 100644 (file)
@@ -1 +1,2 @@
-from .PropertyManager import PropertyManager
+from .Epimetheus import Epimetheus
+
diff --git a/developer/authored/deprecated/ObjectRegistry.py b/developer/authored/deprecated/ObjectRegistry.py
new file mode 100644 (file)
index 0000000..9d30fd9
--- /dev/null
@@ -0,0 +1,113 @@
+#!/usr/bin/env python3
+# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
+
+"""
+ObjectRegistry
+
+Maps Python runtime objects to ProcessLocalId.
+
+Strategies:
+  1. Weak Identity (Preferred): For objects that support weakrefs (instances ,classes).
+     - ID lifetime is bound to object lifetime.
+     - Auto-cleaned on GC.
+  
+  2. Value Identity (Fallback): For immutable primitives (int ,str ,tuple).
+     - ID is bound to the *value* (hash/equality).
+     - Stored strongly (since values like 42 or "red" are conceptually eternal).
+"""
+
+from __future__ import annotations
+
+import weakref
+from typing import Any ,Callable ,Dict ,Optional
+
+from .ProcessLocalId import ProcessLocalIdGenerator ,ProcessLocalId
+
+
+class ObjectRegistry:
+  def __init__(self ,id_gen: ProcessLocalIdGenerator):
+    self._id_gen = id_gen
+    
+    # Strategy 1: Entities (Weakref-able)
+    self._obj_to_id_wkd: "weakref.WeakKeyDictionary[Any ,ProcessLocalId]" = weakref.WeakKeyDictionary()
+    self._id_to_obj_ref: Dict[ProcessLocalId ,weakref.ref] = {}
+    
+    # Strategy 2: Values (Hashable ,not weakref-able)
+    self._value_to_id: Dict[Any ,ProcessLocalId] = {}
+    
+    self._finalizers: Dict[ProcessLocalId ,Callable[[ProcessLocalId] ,None]] = {}
+    self._global_finalizer: Optional[Callable[[ProcessLocalId] ,None]] = None
+
+  def register_finalizer(self ,fn: Callable[[ProcessLocalId] ,None]):
+    """
+    Registers a finalizer callback invoked when any registered *weak-refable* object is GC'd.
+    """
+    self._global_finalizer = fn
+
+  def _on_collect(self ,obj_id: ProcessLocalId):
+    # Only called for Strategy 1 objects
+    ref = self._id_to_obj_ref.pop(obj_id ,None)
+    if(ref is not None):
+      # The WeakKeyDictionary auto-cleans the forward mapping ,
+      # but we double check or clean any edge cases if needed.
+      pass 
+      
+    fn = self._global_finalizer
+    if(fn is not None):
+      fn(obj_id)
+
+  def get_id(self ,obj: Any) -> ProcessLocalId:
+    """
+    Returns the ProcessLocalId for `obj` ,registering it if needed.
+    """
+    # 1. Try WeakRef Strategy (Entities)
+    try:
+      existing = self._obj_to_id_wkd.get(obj)
+      if(existing is not None):
+        return existing
+    except TypeError:
+      # obj is not weakref-able (e.g. int ,str ,tuple ,or list).
+      # Fall through to Strategy 2.
+      pass
+    else:
+      # It IS weakref-able ,but wasn't in the dictionary. Register it.
+      obj_id = self._id_gen.next_id()
+      self._obj_to_id_wkd[obj] = obj_id
+      # Create reverse lookup with callback
+      self._id_to_obj_ref[obj_id] = weakref.ref(obj ,lambda _ref ,oid=obj_id: self._on_collect(oid))
+      return obj_id
+
+    # 2. Try Value Strategy (Primitives)
+    # Note: Mutable non-weakrefables (like standard lists) will fail here because they are unhashable.
+    try:
+      existing = self._value_to_id.get(obj)
+      if(existing is not None):
+        return existing
+      
+      # Register new value
+      obj_id = self._id_gen.next_id()
+      self._value_to_id[obj] = obj_id
+      return obj_id
+    except TypeError:
+      # It is neither weakref-able NOR hashable (e.g. standard list ,dict).
+      raise TypeError(
+        f"ObjectRegistry: cannot track object of type {type(obj)!r}. "
+        "It is neither weakref-able (Entity) nor hashable (Value)."
+      )
+
+  def try_get_object(self ,obj_id: ProcessLocalId) -> Optional[Any]:
+    """
+    Best-effort: returns the live object/value.
+    """
+    # Check Entities
+    ref = self._id_to_obj_ref.get(obj_id)
+    if(ref is not None):
+      return ref()
+      
+    # Check Values
+    # For now ,we assume values identify themselves.
+    for val ,pid in self._value_to_id.items():
+      if(pid == obj_id):
+        return val
+        
+    return None
diff --git a/developer/authored/deprecated/ProcessLocalId.py b/developer/authored/deprecated/ProcessLocalId.py
new file mode 100644 (file)
index 0000000..b57c47c
--- /dev/null
@@ -0,0 +1,52 @@
+#!/usr/bin/env python3
+# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
+
+
+"""
+ProcessLocalId
+
+A process-local identifier used as an internal key.
+
+Design constraint:
+  - NOT intended to be serialized or persisted.
+  - `repr()` intentionally does not reveal the numeric token, to discourage logging/persistence.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True ,slots=True)
+class ProcessLocalId:
+  _n: int
+
+  def __repr__(self) -> str:
+    return "<ProcessLocalId>"
+
+  def __str__(self) -> str:
+    return "<ProcessLocalId>"
+
+  def as_int_UNSAFE(self) -> int:
+    """
+    Returns the raw integer token.
+
+    UNSAFE because:
+      - tokens are process-local
+      - do not write these into files/databases/logs as stable identifiers
+    """
+    return self._n
+
+
+class ProcessLocalIdGenerator:
+  """
+  Monotonic generator; ids are never recycled.
+  """
+  def __init__(self ,start: int = 1):
+    if start < 1: raise ValueError("start must be >= 1")
+    self._next_n: int = start
+
+  def next_id(self) -> ProcessLocalId:
+    n = self._next_n
+    self._next_n += 1
+    return ProcessLocalId(n)
diff --git a/developer/authored/deprecated/Property.py b/developer/authored/deprecated/Property.py
new file mode 100644 (file)
index 0000000..5b33226
--- /dev/null
@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
+
+
+"""
+Property
+
+A Property is itself an entity (it has an Identity id) so that:
+  - properties can have properties
+  - properties can be members of semantic sets
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Optional ,Tuple
+
+from .ProcessLocalId import ProcessLocalId
+
+
+@dataclass(frozen=True ,slots=True)
+class Property:
+  id: ProcessLocalId
+  name_path: Tuple[str ,...]
+  doc: str = ""
+
+  def __repr__(self) -> str:
+    # name_path is safe to reveal; id token is not.
+    return f"<Property {'.'.join(self.name_path)!r}>"
diff --git a/developer/authored/deprecated/PropertyManager.py b/developer/authored/deprecated/PropertyManager.py
new file mode 100644 (file)
index 0000000..36e2b9e
--- /dev/null
@@ -0,0 +1,155 @@
+#!/usr/bin/env python3
+# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
+
+
+"""
+PropertyManager
+
+Core RT property system.
+
+Key decisions vs the earlier `property_manager.py`:
+  - do NOT key by `object_path()` strings (avoids collisions) fileciteturn3file4
+  - runtime objects are keyed by weak identity (ProcessLocalId assigned by ObjectRegistry)
+  - properties are first-class entities (Property has an id), so properties can have properties
+
+This remains process-local and in-memory.
+"""
+
+from __future__ import annotations
+
+from typing import Any ,Dict ,Iterable ,List ,Optional ,Tuple ,Union
+
+from .ProcessLocalId import ProcessLocalIdGenerator ,ProcessLocalId
+from .ObjectRegistry import ObjectRegistry
+from .PropertyStore import PropertyStore
+from .Property import Property
+from .SemanticSets import SemanticSet ,SemanticSetStore
+from .Syntax import SyntaxInstance
+
+
+NamePathLike = Union[str ,List[str] ,Tuple[str ,...]]
+
+
+class PropertyManager:
+  def __init__(self):
+    self._id_gen = ProcessLocalIdGenerator()
+    self._obj_reg = ObjectRegistry(self._id_gen)
+    self._store = PropertyStore()
+    self._sets = SemanticSetStore()
+
+    # Declare-by-name registry
+    self._name_path_to_property: Dict[Tuple[str ,...],Property] = {}
+    self._property_id_to_property: Dict[ProcessLocalId ,Property] = {}
+
+    self._name_path_to_set: Dict[Tuple[str ,...],SemanticSet] = {}
+    self._set_id_to_set: Dict[ProcessLocalId ,SemanticSet] = {}
+
+    # Optional syntax instances (if user chooses to model them)
+    self._syntax_id_to_instance: Dict[ProcessLocalId ,SyntaxInstance] = {}
+
+    # Finalization cleanup
+    self._obj_reg.register_finalizer(self._on_subject_finalized)
+
+  def _on_subject_finalized(self ,subject_id: ProcessLocalId):
+    self._store.remove_subject(subject_id)
+    self._sets.remove_subject(subject_id)
+
+  def _normalize_name_path(self ,name_path: NamePathLike) -> Tuple[str ,...]:
+    if isinstance(name_path ,tuple): return name_path
+    if isinstance(name_path ,list): return tuple(name_path)
+    if isinstance(name_path ,str): return tuple(name_path.split("."))
+    raise TypeError("name_path must be str ,list[str] ,or tuple[str ,...]")
+
+  # -------------------------
+  # Identity acquisition
+  # -------------------------
+  def id_of_py_object(self ,obj: Any) -> ProcessLocalId:
+    return self._obj_reg.get_id(obj)
+
+  def create_syntax_identity(self ,syntax: SyntaxInstance) -> ProcessLocalId:
+    sid = self._id_gen.next_id()
+    self._syntax_id_to_instance[sid] = syntax
+    return sid
+
+  def try_get_syntax(self ,syntax_id: ProcessLocalId) -> Optional[SyntaxInstance]:
+    return self._syntax_id_to_instance.get(syntax_id)
+
+  # -------------------------
+  # Property declaration
+  # -------------------------
+  def declare_property(self ,name_path: NamePathLike ,doc: str = "") -> ProcessLocalId:
+    np = self._normalize_name_path(name_path)
+    existing = self._name_path_to_property.get(np)
+    if existing is not None: return existing.id
+    pid = self._id_gen.next_id()
+    p = Property(pid ,np ,doc)
+    self._name_path_to_property[np] = p
+    self._property_id_to_property[pid] = p
+    return pid
+
+  def property_id(self ,name_path: NamePathLike) -> ProcessLocalId:
+    np = self._normalize_name_path(name_path)
+    p = self._name_path_to_property.get(np)
+    if p is None: raise KeyError(f"Property not declared: {np!r}")
+    return p.id
+
+  def try_get_property(self ,prop_id: ProcessLocalId) -> Optional[Property]:
+    return self._property_id_to_property.get(prop_id)
+
+  # -------------------------
+  # Semantic sets
+  # -------------------------
+  def declare_set(self ,name_path: NamePathLike ,doc: str = "") -> ProcessLocalId:
+    np = self._normalize_name_path(name_path)
+    existing = self._name_path_to_set.get(np)
+    if existing is not None: return existing.id
+    sid = self._id_gen.next_id()
+    s = SemanticSet(sid ,np ,doc)
+    self._name_path_to_set[np] = s
+    self._set_id_to_set[sid] = s
+    return sid
+
+  def add_to_set(self ,subject: Any ,set_id: ProcessLocalId):
+    subject_id = self._coerce_subject_id(subject)
+    self._sets.add_member(set_id ,subject_id)
+
+  def is_in_set(self ,subject: Any ,set_id: ProcessLocalId) -> bool:
+    subject_id = self._coerce_subject_id(subject)
+    return self._sets.has_member(set_id ,subject_id)
+
+  def members(self ,set_id: ProcessLocalId) -> List[ProcessLocalId]:
+    return list(self._sets.members(set_id))
+
+  # -------------------------
+  # Set/get properties
+  # -------------------------
+  def set(self ,subject: Any ,prop: Union[ProcessLocalId ,NamePathLike] ,value: Any):
+    subject_id = self._coerce_subject_id(subject)
+    prop_id = self._coerce_property_id(prop)
+    self._store.set(subject_id ,prop_id ,value)
+
+  def get(self ,subject: Any ,prop: Union[ProcessLocalId ,NamePathLike] ,default: Any = None) -> Any:
+    subject_id = self._coerce_subject_id(subject)
+    prop_id = self._coerce_property_id(prop)
+    return self._store.get(subject_id ,prop_id ,default)
+
+  def has(self ,subject: Any ,prop: Union[ProcessLocalId ,NamePathLike]) -> bool:
+    subject_id = self._coerce_subject_id(subject)
+    prop_id = self._coerce_property_id(prop)
+    return self._store.has(subject_id ,prop_id)
+
+  def subjects_with(self ,prop: Union[ProcessLocalId ,NamePathLike]) -> List[ProcessLocalId]:
+    prop_id = self._coerce_property_id(prop)
+    return list(self._store.subjects_with(prop_id))
+
+  # -------------------------
+  # Coercions
+  # -------------------------
+  def _coerce_subject_id(self ,subject: Any) -> ProcessLocalId:
+    if isinstance(subject ,ProcessLocalId): return subject
+    # For Python runtime objects, we require weakref-able instances.
+    return self._obj_reg.get_id(subject)
+
+  def _coerce_property_id(self ,prop: Union[ProcessLocalId ,NamePathLike]) -> ProcessLocalId:
+    if isinstance(prop ,ProcessLocalId): return prop
+    return self.property_id(prop)
diff --git a/developer/authored/deprecated/PropertyStore.py b/developer/authored/deprecated/PropertyStore.py
new file mode 100644 (file)
index 0000000..bc8f3f3
--- /dev/null
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
+
+
+"""
+PropertyStore
+
+Stores property values and maintains reverse lookups.
+
+This is intentionally process-local and in-memory.
+"""
+
+from __future__ import annotations
+
+from typing import Any ,Dict ,Optional ,Set ,Tuple
+
+from .ProcessLocalId import ProcessLocalId
+
+
+class PropertyStore:
+  def __init__(self):
+    # (subject_id ,property_id) -> value
+    self._values: Dict[Tuple[ProcessLocalId ,ProcessLocalId] ,Any] = {}
+
+    # subject_id -> set(property_id)
+    self._subject_to_props: Dict[ProcessLocalId ,Set[ProcessLocalId]] = {}
+
+    # property_id -> set(subject_id)
+    self._prop_to_subjects: Dict[ProcessLocalId ,Set[ProcessLocalId]] = {}
+
+  def set(self ,subject_id: ProcessLocalId ,prop_id: ProcessLocalId ,value: Any):
+    key = (subject_id ,prop_id)
+    self._values[key] = value
+    self._subject_to_props.setdefault(subject_id ,set()).add(prop_id)
+    self._prop_to_subjects.setdefault(prop_id ,set()).add(subject_id)
+
+  def get(self ,subject_id: ProcessLocalId ,prop_id: ProcessLocalId ,default: Any = None) -> Any:
+    return self._values.get((subject_id ,prop_id) ,default)
+
+  def has(self ,subject_id: ProcessLocalId ,prop_id: ProcessLocalId) -> bool:
+    return (subject_id ,prop_id) in self._values
+
+  def subjects_with(self ,prop_id: ProcessLocalId) -> Set[ProcessLocalId]:
+    return set(self._prop_to_subjects.get(prop_id ,set()))
+
+  def props_of(self ,subject_id: ProcessLocalId) -> Set[ProcessLocalId]:
+    return set(self._subject_to_props.get(subject_id ,set()))
+
+  def remove_subject(self ,subject_id: ProcessLocalId):
+    """
+    Remove all stored properties for a subject (used on finalization).
+    """
+    prop_ids = self._subject_to_props.pop(subject_id ,set())
+    for prop_id in prop_ids:
+      self._values.pop((subject_id ,prop_id) ,None)
+      s = self._prop_to_subjects.get(prop_id)
+      if s is not None:
+        s.discard(subject_id)
+        if not s: self._prop_to_subjects.pop(prop_id ,None)
diff --git a/developer/authored/deprecated/SemanticSets.py b/developer/authored/deprecated/SemanticSets.py
new file mode 100644 (file)
index 0000000..f0fdf48
--- /dev/null
@@ -0,0 +1,55 @@
+#!/usr/bin/env python3
+# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
+
+
+"""
+SemanticSets
+
+Membership sets over identities. Used for semantic typing.
+
+Design:
+  - set_id identifies the set
+  - members are subject ids
+  - reverse index for cleanup
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Dict ,Optional ,Set
+
+from .ProcessLocalId import ProcessLocalId
+
+
+@dataclass(frozen=True ,slots=True)
+class SemanticSet:
+  id: ProcessLocalId
+  name_path: tuple[str ,...]
+  doc: str = ""
+
+  def __repr__(self) -> str:
+    return f"<SemanticSet {'.'.join(self.name_path)!r}>"
+
+
+class SemanticSetStore:
+  def __init__(self):
+    self._members: Dict[ProcessLocalId ,Set[ProcessLocalId]] = {}
+    self._subject_to_sets: Dict[ProcessLocalId ,Set[ProcessLocalId]] = {}
+
+  def add_member(self ,set_id: ProcessLocalId ,subject_id: ProcessLocalId):
+    self._members.setdefault(set_id ,set()).add(subject_id)
+    self._subject_to_sets.setdefault(subject_id ,set()).add(set_id)
+
+  def has_member(self ,set_id: ProcessLocalId ,subject_id: ProcessLocalId) -> bool:
+    return subject_id in self._members.get(set_id ,set())
+
+  def members(self ,set_id: ProcessLocalId) -> Set[ProcessLocalId]:
+    return set(self._members.get(set_id ,set()))
+
+  def remove_subject(self ,subject_id: ProcessLocalId):
+    set_ids = self._subject_to_sets.pop(subject_id ,set())
+    for set_id in set_ids:
+      m = self._members.get(set_id)
+      if m is not None:
+        m.discard(subject_id)
+        if not m: self._members.pop(set_id ,None)
diff --git a/developer/authored/deprecated/Syntax.py b/developer/authored/deprecated/Syntax.py
new file mode 100644 (file)
index 0000000..4fcfa7c
--- /dev/null
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
+
+
+"""
+Syntax
+
+RT syntax identity instances.
+
+We treat "syntax" as AST-level objects:
+  - kind: official-ish AST node kind name (e.g., "ast.FunctionDef")
+  - location: file + span
+  - scope: enclosing syntax identity id (optional)
+  - parts: mapping of part-name to literal or referenced syntax identity id(s)
+
+This module does NOT traverse Python programs. It only defines the data model.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Any ,Dict ,Optional ,Tuple ,Union ,List
+
+from .ProcessLocalId import ProcessLocalId
+
+
+@dataclass(frozen=True ,slots=True)
+class SourceSpan:
+  file_path: str
+  lineno: int
+  col: int
+  end_lineno: int
+  end_col: int
+
+
+SyntaxPartValue = Union[
+  None
+  ,bool
+  ,int
+  ,float
+  ,str
+  ,ProcessLocalId
+  ,List["SyntaxPartValue"]
+  ,Dict[str ,"SyntaxPartValue"]
+]
+
+
+@dataclass(frozen=True ,slots=True)
+class SyntaxInstance:
+  """
+  A single syntax node instance.
+
+  NOTE: many syntax nodes have no identifier-name. Name-like things (identifiers)
+  appear as child nodes or literals inside `parts`.
+  """
+  kind: str
+  span: SourceSpan
+  scope_id: Optional[ProcessLocalId] = None
+  parts: Dict[str ,SyntaxPartValue] = None
diff --git a/developer/authored/test_SymbolFactory.py b/developer/authored/test_SymbolFactory.py
new file mode 100755 (executable)
index 0000000..8bc21dc
--- /dev/null
@@ -0,0 +1,116 @@
+#!/usr/bin/env python3
+# -*- mode: python; coding: utf-8; python-indent-offset: 2 -*-
+
+"""
+Tests for Symbol.Instance constraints.
+"""
+
+import unittest
+from Symbol import Symbol
+
+class TestSymbol(unittest.TestCase):
+
+  def test_null_symbol_exists(self):
+    """
+    Requirement: Symbol.null exists and is Token 0.
+    """
+    null_sym = Symbol.null
+    self.assertIsNotNone(null_sym)
+    self.assertEqual(null_sym.name ,"Null")
+    self.assertEqual(null_sym.doc ,"The Null Symbol")
+
+  def test_distinctness(self):
+    """
+    Requirement: Two distinct originals will always be not equal.
+    """
+    s1 = Symbol.make()
+    s2 = Symbol.make()
+
+    self.assertNotEqual(s1 ,s2)
+    self.assertIsNot(s1 ,s2)
+    self.assertNotEqual(s1 ,Symbol.null)
+
+  def test_name_immutability(self):
+    """
+    Requirement: Name can be set once, but never changed.
+    """
+    # Case 1: Set at creation
+    s1 = Symbol.make(name="Alpha")
+    self.assertEqual(s1.name ,"Alpha")
+
+    # Attempt to change
+    with self.assertRaises(RuntimeError):
+      s1.name = "Beta"
+
+    # Case 2: Late binding
+    s2 = Symbol.make()
+    self.assertIsNone(s2.name)
+
+    s2.name = "Gamma"
+    self.assertEqual(s2.name ,"Gamma")
+
+    # Attempt to change after late bind
+    with self.assertRaises(RuntimeError):
+      s2.name = "Delta"
+
+  def test_doc_immutability(self):
+    """
+    Requirement: Doc can be set once, but never changed.
+    """
+    # Case 1: Set at creation
+    s1 = Symbol.make(doc="Original Doc")
+    self.assertEqual(s1.doc ,"Original Doc")
+
+    with self.assertRaises(RuntimeError):
+      s1.doc = "New Doc"
+
+    # Case 2: Late binding
+    s2 = Symbol.make()
+    self.assertEqual(s2.doc ,"") # Default is empty string
+
+    s2.doc = "Late Doc"
+    self.assertEqual(s2.doc ,"Late Doc")
+
+    with self.assertRaises(RuntimeError):
+      s2.doc = "Changed Doc"
+
+  def test_doc_empty_string_behavior(self):
+    """
+    Requirement: Setting doc to "" is ignored and does not count as 'setting' it.
+    """
+    s1 = Symbol.make()
+
+    # Setting empty string should be a no-op
+    s1.doc = ""
+    self.assertEqual(s1.doc ,"")
+
+    # Should still be able to set it later because "" didn't lock it
+    s1.doc = "Real Doc"
+    self.assertEqual(s1.doc ,"Real Doc")
+
+    # NOW it is locked
+    with self.assertRaises(RuntimeError):
+      s1.doc = "Trying to change"
+
+  def test_property_access(self):
+    """
+    Requirement: Read/Write via properties.
+    """
+    s = Symbol.make()
+    s.name = "Velocity"
+    s.doc = "m/s"
+
+    self.assertEqual(s.name ,"Velocity")
+    self.assertEqual(s.doc ,"m/s")
+    self.assertIsInstance(s ,Symbol.Instance)
+
+  def test_opaque_representation(self):
+    """
+    Requirement: repr() reveals no internal token.
+    """
+    s1 = Symbol.make()
+    self.assertEqual(repr(s1) ,"<Symbol.Instance>")
+
+
+if __name__ == '__main__':
+  unittest.main()
index 5661740..85ee1ad 100644 (file)
@@ -88,7 +88,7 @@
         In Epimetheus, we use a dictionary to give a <RT-term>symbol</RT-term> a name. The names need not meet the requirements imposed on a <RT-term>symbol instance</RT-term>, but it can be confusing when they don't. This is avoided in other <RT-term>symbol</RT-term> systems by implementing <RT-term>symbol</RT-term>s over character strings, and using the character string as both the name and the instance.
        </p>
 
-      <h2>Required Properties</h2>
+      <h3>Required Properties</h3>
 
       <p>
         Any two, or by transitivity, any number of, <RT-term>symbol instance</RT-term>s can be compared for equality, say <RT-code>x == y</RT-code>. A comparison between <RT-term>symbol instance</RT-term>s will always return <RT-code>True</RT-code> or <RT-code>False</RT-code>.
       </p>
 
 
-      <h2>What <em>is</em> a Symbol?</h2>
+      <h3>What <em>is</em> a Symbol?</h3>
 
       <p>
         Only <RT-term>symbol instance</RT-term>s exist at runtime, so a <RT-term>symbol</RT-term> is never manipulated directly.
         Think about it this way: you are sitting in a pub of an inn, and a stranger walks in. Though you know the stranger's current <RT-term>destination</RT-term>, you might not know where he came from.
       </blockquote>
 
-      <h3>Discrete Function</h3>
+      <h2>Discrete Function</h2>
       <p>
         Now consider a <RT-term>tape</RT-term>, say called <var>F</var>, where each cell in F holds a <RT-term>path</RT-term>. As a <RT-term>path</RT-term> is a <RT-term>tape</RT-term>, the structure of <var>F</var> is that of a <RT-term>tape</RT-term> of <RT-term>tape</RT-term>s.
       </p>