perform minor, partial reformatting

.gitignore

@@ -1,18 +1,19 @@
-# generic py
+# generic
 __pycache__/
-.pytest_cache/
 *.egg-info/
-.ipynb_checkpoints/
-.pytest_cache/
 .python-version
 
-# vendor and build files
+# package-specific
+.ipynb_checkpoints/
+.pytest_cache/
+
+# vendor/build files
 dist/
 build/
-docs/_autoref/
+doc/_autoref/
-docs/_autosummary/
+doc/_autosummary/
-docs/_build/
+doc/_build/
 
-# local
+# misc local
-notebooks/
 /Makefile
+notebooks/

README.md

@@ -1,35 +1,36 @@
 # Overview
-`co3` is a lightweight Python ORM for hierarchical storage management. It implements a
+`co3` is a lightweight Python ORM for hierarchical storage management. It
-general type system for defining database components like relations, schemas, engines,
+implements a general type system for defining database components like
-etc. Objects inheriting from the `CO3` base class can then define data transformations
+relations, schemas, engines, etc. Objects inheriting from the `CO3` base class
-that connect to database components, and can be automatically collected for coordinated
+can then define data transformations that connect to database components, and
-database insertion.
+can be automatically collected for coordinated database insertion.
 
-`co3` attempts to provide a general interface for interacting with storage media (e.g.,
+`co3` attempts to provide a general interface for interacting with storage
-databases, pickled objects, VSS framework, in-memory key-value stores, etc). The following
+media (e.g., databases, pickled objects, VSS framework, in-memory key-value
-top-level classes capture the bulk of the operational model:
+stores, etc). The following top-level classes capture the bulk of the
+operational model:
 
-- **Database**: reference to a storage medium, with an `Accessor` for accessing data,
+- **Database**: reference to a storage medium, with an `Accessor` for accessing
-  `Manager` for managing database state, and an `Engine` for managing connections and
+  data, `Manager` for managing database state, and an `Engine` for managing
-  external operations.
+  connections and external operations.
-- **Accessor**: provides access to stored items in a `Database`, typically via a supported
+- **Accessor**: provides access to stored items in a `Database`, typically via
-  `select` operation over known `Component` types
+  a supported `select` operation over known `Component` types
-- **Manager**: manages database storage state (e.g., supported inserts or database sync
+- **Manager**: manages database storage state (e.g., supported inserts or
-  operations)
+  database sync operations)
-- **Mapper**: associates `CO3` types with `Schema` components, and provides automatic
+- **Mapper**: associates `CO3` types with `Schema` components, and provides
-  collection and composition operations for supported items
+  automatic collection and composition operations for supported items
-- **Collector**: collects data from defined `CO3` type transformations and prepares for
+- **Collector**: collects data from defined `CO3` type transformations and
-  `Database` insert operations
+  prepares for `Database` insert operations
-- **Component**: atomic storage groups for databases (i.e., generalized notion of a
+- **Component**: atomic storage groups for databases (i.e., generalized notion
-  "relation" in relational algebra).
+  of a "relation" in relational algebra).
 - **Indexer**: automatic caching of supported access queries to a `Database`
 - **Schema**: general schema analog for grouping related `Component` sets
-- **Differ**: facilitates set operations on results from selectable resources (e.g.,
+- **Differ**: facilitates set operations on results from selectable resources
-  automatic comparison between file data on disk and file rows in a SQL database)
+  (e.g., automatic comparison between file data on disk and file rows in a SQL
-- **Syncer**: generalized syncing procedure for items between data resources (e.g.,
+  database)
-  syncing new, modified, and deleted files from disk to a SQL database that stores file
+- **Syncer**: generalized syncing procedure for items between data resources
-  metadata).
+  (e.g., syncing new, modified, and deleted files from disk to a SQL database
-
+  that stores file metadata).
-The **CO3** an abstract base class then makes it easy to integrate this model with regular
-Python object hierarchies that can be mapped to a storage schema.
 
+The **CO3** an abstract base class then makes it easy to integrate this model
+with regular Python object hierarchies that can be mapped to a storage schema.

co3/accessor.py

@@ -1,7 +1,7 @@
 '''
-Provides access to an underlying schema through a supported set of operations. Class
+Provides access to an underlying schema through a supported set of operations.
-methods could be general, high-level SQL wrappers, or convenience functions for common
+Class methods could be general, high-level SQL wrappers, or convenience
-schema-specific queries.
+functions for common schema-specific queries.
 '''
 import time
 import inspect
@@ -16,13 +16,14 @@ from co3.component import Component
 
 class Accessor[C: Component](metaclass=ABCMeta):
     '''
-    Access wrapper class for complex queries and easy integration with Composer tables.
+    Access wrapper class for complex queries and easy integration with Composer
-    Implements high-level access to things like common constrained SELECT queries.
+    tables. Implements high-level access to things like common constrained
+    SELECT queries.
 
     Instance variables:
         access_log: time-indexed log of access queries performed
     '''
-    def __init__(self):
+    def __init__(self) -> None:
         self.access_log = {}
 
     def log_access(self, stmt):

co3/co3.py

@@ -1,8 +1,9 @@
 '''
-CO3 is an abstract base class for scaffolding object hierarchies and managing operations
+CO3 is an abstract base class for scaffolding object hierarchies and managing
-with associated database schemas. It facilitates something like a "lightweight ORM" for
+operations with associated database schemas. It facilitates something like a
-classes/tables/states with fixed transformations of interest. The canonical use case is
+"lightweight ORM" for classes/tables/states with fixed transformations of
-managing hierarchical document relations, format conversions, and syntactical components.
+interest. The canonical use case is managing hierarchical document relations,
+format conversions, and syntactical components.
 
 Generic collation syntax:
 
@@ -22,12 +23,13 @@ Generic collation syntax:
 
 .. admonition:: On multi-key attachment
 
-    One possible quirk of the current collation registry scheme is the rather black and
+    One possible quirk of the current collation registry scheme is the rather
-    white nature of key attachment. You either specify a single key, possibly to several
+    black and white nature of key attachment. You either specify a single key,
-    groups, or allow any key via passthrough under an implicit group. There's no explicit
+    possibly to several groups, or allow any key via passthrough under an
-    "multi-key" pattern to make use of here, be it through "restricted passthrough"
+    implicit group. There's no explicit "multi-key" pattern to make use of
-    (method still parameterized by the key, but only allows keys from a provided list) or
+    here, be it through "restricted passthrough" (method still parameterized by
-    just simple duplicated attachment. To demonstrate via the above example:
+    the key, but only allows keys from a provided list) or just simple
+    duplicated attachment. To demonstrate via the above example:
 
     .. code-block:: python
 
@@ -54,8 +56,8 @@ Generic collation syntax:
 
                 ...
 
-    or with a central handler and separate collation points (at least when the key list is
+    or with a central handler and separate collation points (at least when the
-    small):
+    key list is small):
 
     .. code-block:: python
 
@@ -71,38 +73,41 @@ Generic collation syntax:
             def key2(self):
                 self._handle_supported_keys('key2')
 
-    The former scales better and allows general key rejection patterns if needed, while
+    The former scales better and allows general key rejection patterns if
-    the latter integrates a bit better with the formal collation process, e.g., will
+    needed, while the latter integrates a bit better with the formal collation
-    throw ``ValueErrors`` based on key mismatches automatically.
+    process, e.g., will throw ``ValueErrors`` based on key mismatches
+    automatically.
 '''
 import inspect
 import logging
 from collections import defaultdict
-from functools import wraps, partial
 
 
 logger = logging.getLogger(__name__)
 
+
 def collate(key, groups=None):
     '''
     Collation decorator for CO3 subtype action registry.
 
-    Dynamic decorator; can be used as ``collate`` without any arguments, or with all. In
+    Dynamic decorator; can be used as ``collate`` without any arguments, or
-    the former case, ``key`` will be a function, so we check for this.
+    with all. In the former case, ``key`` will be a function, so we check for
+    this.
 
     .. admonition:: Usage
 
-        Collation registration is the process of exposing various actions for use in
+        Collation registration is the process of exposing various actions for
-        **hierarchical collection** (see ``Mapper.collect``). Collation *keys* are unique
+        use in **hierarchical collection** (see ``Mapper.collect``). Collation
-        identifiers of a particular action that emits data. Keys can belong to an arbitrary
+        *keys* are unique identifiers of a particular action that emits data.
-        number of *groups*, which serve as semantically meaningful collections of similar
+        Keys can belong to an arbitrary number of *groups*, which serve as
-        actions. Group assignment also determines the associated *collation component*
+        semantically meaningful collections of similar actions. Group
-        to be used as a storage target; the results of actions $K_G$ belonging to group
+        assignment also determines the associated *collation component* to be
-        $G$ will all be stored in the attached $G$-component. Specification of key-group
+        used as a storage target; the results of actions $K_G$ belonging to
-        relations can be done in a few ways:
+        group $G$ will all be stored in the attached $G$-component.
+        Specification of key-group relations can be done in a few ways:
 
-        - Explicit key-group specification: a specific key and associated groups can be
+        - Explicit key-group specification: a specific key and associated
-          provided as arguments to the decorator:
+          groups can be provided as arguments to the decorator:
 
           .. code-block:: python
 
@@ -127,14 +132,14 @@ def collate(key, groups=None):
                   ...
               }
 
-          If ``groups`` is left unspecified, the key will be attached to the default
+          If ``groups`` is left unspecified, the key will be attached to the
-          ``None`` group.
+          default ``None`` group.
 
-        - Implicit key-group association: in some cases, you may want to support an entire
+        - Implicit key-group association: in some cases, you may want to
-          "action class," and associate any operations under the class to the same storage
+          support an entire "action class," and associate any operations under
-          component. Here we still use the notion of connecting groups to components, but
+          the class to the same storage component. Here we still use the notion
-          allow the key to be dynamically specified and passed through to the collation
+          of connecting groups to components, but allow the key to be
-          method:
+          dynamically specified and passed through to the collation method:
 
           .. code-block:: python
 
@@ -160,27 +165,31 @@ def collate(key, groups=None):
 
           A few important notes:
 
-          - Implicit key-group specifications attach the *group* to a single method,
+          - Implicit key-group specifications attach the *group* to a single
-            whereas in the explicit case, groups can be affiliated with many keys. When
+            method, whereas in the explicit case, groups can be affiliated with
-            explicitly provided, only those exact key values are supported. But in the
+            many keys. When explicitly provided, only those exact key values
-            implicit case, *any* key is allowed; the group still remains a proxy for the
+            are supported. But in the implicit case, *any* key is allowed; the
-            entire action class, but without needing to map from specifically stored key
+            group still remains a proxy for the entire action class, but
-            values. That is, the utility of the group remains consistent across implicit
+            without needing to map from specifically stored key values. That
+            is, the utility of the group remains consistent across implicit
             and explicit cases, but stores the associations differently.
-          - The ``None`` key, rather than point to a ``(<method>, <group-list>)`` tuple,
+          - The ``None`` key, rather than point to a ``(<method>,
-            instead points to a dictionary of ``group``-``method`` pairs. When attempting
+            <group-list>)`` tuple, instead points to a dictionary of
-            execute a key under a particular group, the group registry indicates
+            ``group``-``method`` pairs. When attempting execute a key under a
-            whether the key is explicitly supported. If ``None`` is present for the group,
+            particular group, the group registry indicates whether the key is
-            then ``key_registry[None][<group-name>]`` can be used to recover the method
+            explicitly supported. If ``None`` is present for the group, then
-            implicitly affiliated with the key (along with any other key under the group).
+            ``key_registry[None][<group-name>]`` can be used to recover the
-          - When any method has been implicitly registered, *any* key (even when
+            method implicitly affiliated with the key (along with any other key
-            attempting to specify an explicit key) will match that group. This can
+            under the group).
-            effectively mean keys are not unique when an implicit group has been
+          - When any method has been implicitly registered, *any* key (even
-            registered. There is a protection in place here, however; in methods like
+            when attempting to specify an explicit key) will match that group.
-            ``CO3.collate`` and ``Mapper.collect``, an implicit group must be directly
+            This can effectively mean keys are not unique when an implicit
-            named in order for a given key to be considered. That is, when attempting
+            group has been registered. There is a protection in place here,
-            collation outside specific group context, provided keys will only be
+            however; in methods like ``CO3.collate`` and ``Mapper.collect``, an
-            considered against explicitly registered keys.
+            implicit group must be directly named in order for a given key to
+            be considered. That is, when attempting collation outside specific
+            group context, provided keys will only be considered against
+            explicitly registered keys.
     '''
     func = None
     if inspect.isfunction(key):
@@ -200,6 +209,7 @@ def collate(key, groups=None):
 
     return decorator
 
+
 class FormatRegistryMeta(type):
     '''
     Metaclass handling collation registry at the class level.
@@ -225,8 +235,8 @@ class FormatRegistryMeta(type):
                 for _, method in methods:
                     register_action(method)
 
-        # add final registered formats for the current class, overwriting any found in
+        # add final registered formats for the current class, overwriting any
-        # superclass chain
+        # found in superclass chain
         for attr_name, attr_value in attrs.items():
             register_action(attr_value)
 
@@ -235,41 +245,49 @@ class FormatRegistryMeta(type):
 
         return super().__new__(cls, name, bases, attrs)
 
+
 class CO3(metaclass=FormatRegistryMeta):
     '''
     Base class supporting the central "COllate, COllect, COmpose" paradigm.
 
-    - Collate: organize and transform conversion outputs, possibly across class components
+    - Collate: organize and transform conversion outputs, possibly across class
-    - Collect: gather core attributes, conversion data, and subcomponents for DB insertion
+      components
-    - Compose: construct object-associated DB table references through the class hierarchy
+    - Collect: gather core attributes, conversion data, and subcomponents for
+      DB insertion
+    - Compose: construct object-associated DB table references through the
+      class hierarchy
 
     .. admonition:: on action groups
 
-        Group keys are simply named collections to make it easy for storage components to
+        Group keys are simply named collections to make it easy for storage
-        be attached to action subsets. They do _not_ augment the action registration
+        components to be attached to action subsets. They do _not_ augment the
-        namespace, meaning the action key should still be unique; the group key is purely
+        action registration namespace, meaning the action key should still be
-        auxiliary.
+        unique; the group key is purely auxiliary.
 
         Action methods can also be attached to several groups, in case there is
-        overlapping utility within or across schemas or storage media. In this case, it
+        overlapping utility within or across schemas or storage media. In this
-        becomes particularly critical to ensure registered ``collate`` methods really are
+        case, it becomes particularly critical to ensure registered ``collate``
-        just "gathering results" from possibly heavy-duty operations, rather than
+        methods really are just "gathering results" from possibly heavy-duty
-        performing them when called, so as to reduce wasted computation.
+        operations, rather than performing them when called, so as to reduce
+        wasted computation.
 
     .. admonition:: New: collation caching
 
         To help facilitate the common pattern of storing collation results, a
-        ``collate_cache`` parameter has been added to store key-group indexed collation
+        ``collate_cache`` parameter has been added to store key-group indexed
-        results. (Note: now requires explicit superclass instantiation.)
+        collation results. (Note: now requires explicit superclass
+        instantiation.)
     '''
+
     def __init__(self):
         self._collate_cache = {}
 
     @property
     def attributes(self):
         '''
-        Method to define how a subtype's inserts should be handled under ``collect`` for
+        Method to define how a subtype's inserts should be handled under
-        canonical attributes, i.e., inserts to the type's table.
+        ``collect`` for canonical attributes, i.e., inserts to the type's
+        table.
         '''
         return vars(self)
 
@@ -284,14 +302,15 @@ class CO3(metaclass=FormatRegistryMeta):
     def collation_attributes(self, key, group):
         '''
         Return "connective" collation component data, possibly dependent on
-        instance-specific attributes and the action arguments. This is typically the
+        instance-specific attributes and the action arguments. This is
-        auxiliary structure that may be needed to attach to responses from registered
+        typically the auxiliary structure that may be needed to attach to
-        ``collate`` calls to complete inserts.
+        responses from registered ``collate`` calls to complete inserts.
 
-        Note: this method is primarily used by ``Mapper.collect()``, and is called just
+        Note: this method is primarily used by ``Mapper.collect()``, and is
-        prior to collector send-off for collation inserts and injected alongside collation
+        called just prior to collector send-off for collation inserts and
-        data. Common structure in collation components can make this function easy to
+        injected alongside collation data. Common structure in collation
-        define, independent of action group for instance.
+        components can make this function easy to define, independent of action
+        group for instance.
         '''
         return {}
 
@@ -350,5 +369,3 @@ class CO3(metaclass=FormatRegistryMeta):
             self._collate_cache[(key, group)] = result
 
         return result
-
-

co3/component.py

@@ -2,19 +2,21 @@ class Component[T]:
     '''
     Component
 
-    General wrapper for storage components to be used in various database contexts. Relations
+    General wrapper for storage components to be used in various database
-    can be thought of generally as named data containers/entities serving as a fundamental
+    contexts. Relations can be thought of generally as named data
-    abstractions within particular storage protocols.
+    containers/entities serving as a fundamental abstractions within particular
+    storage protocols.
     '''
-    def __init__(self, name, obj: T):
+
+    def __init__(self, name, obj: T) -> None:
         self.name = name
         self.obj  = obj
 
-    def __str__(self):
+    def __str__(self) -> str:
         return f'<Component ({self.__class__.__name__})> {self.name}'
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return f'<Component ({self.__class__.__name__})> {self.name}'
 
-    def get_attributes(self):
+    def get_attributes(self) -> dict:
         raise NotImplementedError

co3/components/__init__.py

@@ -1,8 +1,9 @@
 '''
 Dev note:
-    Any reason to have ComposeableComponents and Relations as separate types? The thought
+    Any reason to have ComposableComponents and Relations as separate types?
-    is that there may be some possible Component types we want to be able to Compose that
+    The thought is that there may be some possible Component types we want to
-    wouldn't logically be Relations. But the gap here might be quite small
+    be able to Compose that wouldn't logically be Relations. But the gap here
+    might be quite small
 '''
 
 from typing import Self
@@ -29,9 +30,9 @@ class ComposableComponent[T](Component[T], metaclass=ABCMeta):
 # relational databases
 class Relation[T](ComposableComponent[T]):
     '''
-    Relation base for tabular components to be used in relation DB settings. Attempts to
+    Relation base for tabular components to be used in relation DB settings.
-    adhere to the set-theoretic base outlined in the relational model [1]. Some
+    Attempts to adhere to the set-theoretic base outlined in the relational
-    terminology:
+    model [1]. Some terminology:
 
     Relation: table-like container
     | -> Heading: set of attributes
@@ -43,15 +44,16 @@ class Relation[T](ComposableComponent[T]):
     [1]: https://en.wikipedia.org/wiki/Relational_model#Set-theoretic_formulation
 
     Note: development tasks
-        As it stands, the Relation skeleton is incredibly lax compared to the properties and
+        As it stands, the Relation skeleton is incredibly lax compared to the
-        operations that should be formally available, according its pure relational algebra
+        properties and operations that should be formally available, according
-        analog. 
+        its pure relational algebra analog. 
 
-        Relations are also generic up to a type T, which ultimately serves as the base object
+        Relations are also generic up to a type T, which ultimately serves as
-        for Relation instances. We aren't attempting to implement some generally useful
+        the base object for Relation instances. We aren't attempting to
-        table-like class here; instead we're just exposing a lightweight interface that's
+        implement some generally useful table-like class here; instead we're
-        needed for a few CO3 contexts, and commonly off-loading most of the heavy-lifting to
+        just exposing a lightweight interface that's needed for a few CO3
-        true relation objects like SQLAlchemy tables.
+        contexts, and commonly off-loading most of the heavy-lifting to true
+        relation objects like SQLAlchemy tables.
     '''
     def compose(
         self,
@@ -65,8 +67,8 @@ class SQLTable(Relation[SQLTableLike]):
     @classmethod
     def from_table(cls, table: sa.Table):
         '''
-        Note that the sa.Table type is intentional here; not all matching types for
+        Note that the sa.Table type is intentional here; not all matching types
-        SQLTableLike have a defined ``name`` property
+        for SQLTableLike have a defined ``name`` property
         '''
         return cls(table.name, table)
 
@@ -78,7 +80,8 @@ class SQLTable(Relation[SQLTableLike]):
         Provide column:default pairs for a provided SQLAlchemy table.
 
         Parameters:
-            include_all: whether to include all columns, even those without explicit defaults
+            include_all: whether to include all columns, even those without
+                explicit defaults
         '''
         default_values = {}
         for column in self.get_attributes():
@@ -87,8 +90,8 @@ class SQLTable(Relation[SQLTableLike]):
             elif column.nullable:
                 default_values[column.name] = None
             else:
-                # assume empty string if include_all and col has no explicit default 
+                # assume empty string if include_all and col has no explicit
-                # and isn't nullable
+                # default and isn't nullable
                 if include_all and column.name != 'id':
                     default_values[column.name] = ''
 

co3/database.py

@@ -1,19 +1,20 @@
 '''
 Database
 
-Central object for defining storage protocol-specific interfaces. The database wraps up
+Central object for defining storage protocol-specific interfaces. The database
-central items for interacting with database resources, namely the Accessor and Manager
+wraps up central items for interacting with database resources, namely the
-objects.
+Accessor and Manager objects.
 
-The Database type hierarchy attempts to be exceedingly general; SQL-derivatives should
+The Database type hierarchy attempts to be exceedingly general; SQL-derivatives
-subclass from the RelationalDatabase subtype, for example, which itself becomes a new
+should subclass from the RelationalDatabase subtype, for example, which itself
-generic via a type dependence on Relation.
+becomes a new generic via a type dependence on Relation.
 
-While relying no many constituent pieces, Databases intend to provide all needed objects
+While relying on many constituent pieces, Databases intend to provide all
-under one roof. This includes the Engine (opens up connections to the database), Accessors
+needed objects under one roof. This includes the Engine (opens up connections
-(running select-like queries on DB data), Managers (updating DB state with sync
+to the database), Accessors (running select-like queries on DB data), Managers
-insert-like actions), and Indexers (systematically caching Accessor queries). Generalized
+(updating DB state with sync insert-like actions), and Indexers (systematically
-behavior is supported by explicitly leveraging the individual components. For example,
+caching Accessor queries). Generalized behavior is supported by explicitly
+leveraging the individual components. For example,
 
 .. code-block:: python
 
@@ -28,9 +29,9 @@ behavior is supported by explicitly leveraging the individual components. For ex
             data
         )
 
-The Database also supports a few directly callable methods for simplified interaction.
+The Database also supports a few directly callable methods for simplified
-These methods manage a connection context internally, passing them through the way they
+interaction. These methods manage a connection context internally, passing them
-might otherwise be handled explicitly, as seen above.
+through the way they might otherwise be handled explicitly, as seen above.
 
 .. code-block:: python
 
@@ -41,17 +42,18 @@ might otherwise be handled explicitly, as seen above.
 
 .. admonition:: on explicit connection contexts
 
-    Older models supported Accessors/Managers that housed their own Engine instances, and
+    Older models supported Accessors/Managers that housed their own Engine
-    when performing actions like ``insert``, the Engine would be passed all the way through
+    instances, and when performing actions like ``insert``, the Engine would be
-    until a Connection could be spawned, and in that context the single action would be
+    passed all the way through until a Connection could be spawned, and in that
-    made. This model forfeits a lot of connection control, preventing multiple actions
+    context the single action would be made. This model forfeits a lot of
-    under a single connection.
+    connection control, preventing multiple actions under a single connection.
 
-    The newer model now avoids directly allowing Managers/Accessors access to their own
+    The newer model now avoids directly allowing Managers/Accessors access to
-    engines, and instead they expose methods that explicitly require Connection objects.
+    their own engines, and instead they expose methods that explicitly require
-    This means a user can invoke these methods in their own Connection contexts (seen
+    Connection objects. This means a user can invoke these methods in their own
-    above) and group up operations as they please, reducing overhead. The Database then
+    Connection contexts (seen above) and group up operations as they please,
-    wraps up a few single-operation contexts where outer connection control is not needed.
+    reducing overhead. The Database then wraps up a few single-operation
+    contexts where outer connection control is not needed.
 '''
 import logging
 
@@ -68,27 +70,29 @@ class Database[C: Component]:
     '''
     Generic Database definition
 
-    Generic to both a Component (C), and an Engine resource type (R). The Engine's
+    Generic to both a Component (C), and an Engine resource type (R). The
-    generic openness must be propagated here, as it's intended to be fully abstracted away
+    Engine's generic openness must be propagated here, as it's intended to be
-    under the Database roof. Note that we cannot explicitly use an Engine type in its
+    fully abstracted away under the Database roof. Note that we cannot
-    place, as it obscures its internal resource type dependence when we need it for
+    explicitly use an Engine type in its place, as it obscures its internal
-    hinting here in ``__init__``.
+    resource type dependence when we need it for hinting here in ``__init__``.
 
     .. admonition:: Development TODO list
 
-        Decide on official ruling for assigning Schema objects, and verifying any
+        Decide on official ruling for assigning Schema objects, and verifying
-        attempted Component-based actions (e.g., inserts, selects) to belong to or be a
+        any attempted Component-based actions (e.g., inserts, selects) to
-        composition of Components within an attached Schema. Reasons for: helps complete
+        belong to or be a composition of Components within an attached Schema.
-        the sense of a "Database" here programmatically, incorporating a more structurally
+        Reasons for: helps complete the sense of a "Database" here
-        accurate representation of allowed operations, and prevent possible attribute and
+        programmatically, incorporating a more structurally accurate
-        type collisions. Reasons against: generally not a huge concern to align Schemas as
+        representation of allowed operations, and prevent possible attribute
-        transactions will rollback, broadly increases a bit of bulk, and users often
+        and type collisions. Reasons against: generally not a huge concern to
-        expected know which components belong to a particular DB. Leaning more to **for**,
+        align Schemas as transactions will rollback, broadly increases a bit of
-        and would only apply to the directly supported method passthroughs (and thus would
+        bulk, and users often expected know which components belong to a
-        have no impact on independent methods like ``Accessor.raw_select``). Additionally,
+        particular DB. Leaning more to **for**, and would only apply to the
+        directly supported method passthroughs (and thus would have no impact
+        on independent methods like ``Accessor.raw_select``). Additionally,
         even if component clashes don't pose serious risk, it can be helpful to
-        systematically address the cases where a misalignment is occurring (by having
+        systematically address the cases where a misalignment is occurring (by
-        helpful ``verify`` methods that can be ran before any actions).
+        having helpful ``verify`` methods that can be ran before any actions).
     '''
     _accessor_cls: type[Accessor[C]] = Accessor[C]
     _manager_cls:  type[Manager[C]]  = Manager[C]

co3/databases/sql.py

@@ -1,20 +1,18 @@
 import sqlalchemy as sa
 
-from co3.database import Database, Engine
-
-from co3.accessors.sql import RelationalAccessor, SQLAccessor
-from co3.managers.sql  import RelationalManager,  SQLManager
-
 from co3.engines import SQLEngine
+from co3.database import Database
 from co3.components import Relation, SQLTable
+from co3.managers.sql import RelationalManager, SQLManager
+from co3.accessors.sql import RelationalAccessor, SQLAccessor
 
 
 class RelationalDatabase[C: Relation](Database[C]):
     '''
     accessor/manager assignments satisfy supertype's type settings;
-    ``TabluarAccessor[Self, C]`` is of type ``type[RelationalAccessor[Self, C]]``
+    ``TabluarAccessor[Self, C]`` is of type ``type[RelationalAccessor[Self,
-    (and yes, ``type[]`` specifies that the variable is itself being set to a type or a
+    C]]`` (and yes, ``type[]`` specifies that the variable is itself being set
-    class, rather than a satisfying _instance_)
+    to a type or a class, rather than a satisfying _instance_)
     '''
     _accessor_cls: type[RelationalAccessor[C]] = RelationalAccessor[C]
     _manager_cls:  type[RelationalManager[C]]  = RelationalManager[C]

co3/indexer.py

@@ -11,12 +11,10 @@ logger = logging.getLogger(__name__)
 
 class Indexer:
     '''
-    Indexer class
+    Indexer base class
 
     Provides restricted access to an underlying Accessor to enable more efficient, superficial
-    caching.
+    caching. Note that cache clearing is to be handled by a wrapper class, like the Database.
-
-    Cache clearing is to be handled by a wrapper class, like the Database.
 
     Caching occurs at the class level, with indexes prefixed by table's origin Composer.
     This means that cached selects/group-bys will be available regardless of the provided
@@ -317,6 +315,7 @@ class Indexer:
 
         return list(group_by_idx.values())
 
+
 class CacheBlock:
     '''
     Wraps up a set of query parameters for a specific entity, and provides cached access

co3/medium.py

@@ -1,6 +1,8 @@
 import logging
 from contextlib import contextmanager
 
+from co3.engine import Engine, Connection, Resource, Group
+
 
 logger = logging.getLogger(__name__)
 
@@ -10,11 +12,14 @@ class Medium[R: Resource]:
 
     A Resource space
     '''
-    def __init__(self, scope):
+    _engine_cls: type[Engine] = Engine
+ 
+    def __init__(self, *scope_args, **scope_kwargs):
+        self.engine = self._engine_cls(*engine_args, **engine_kwargs)
         pass
         
     @contextmanager
-    def connect(self, timeout=None):
+    def connect(self, timeout=None) -> Connection:
         '''
         Open a connection to the database specified by the resource. Exactly what the
         returned connection looks like remains relatively unconstrained given the wide
@@ -22,21 +27,59 @@ class Medium[R: Resource]:
         with-statement contexts, constituting an "interaction session" with the database
         (i.e., allowing several actions to be performed using the same connection).
         '''
-        raise NotImplementedError
+        return self.engine.connect(timeout=timeout)
 
     def execute(self, query: Query[QL]):
         pass
 
 
-class BrowsableMedium[R: Resource](Medium[R]):
+class ReadableMedium[R: Resource](Medium[R]):
-    def browse(self, uri: URI[R]):
+    def _resolve_relative_uri(self, protocol, value):
+        '''
+        Subclass to implement: fetch child object for supported protocol, i.e., single
+        component subpath
+        '''
+        ...
+
+    def resolve_uri(self, uri: URI) -> ResourceCollection:
+        assert uri.protocols[0] in self.supported_protocols
+
+        obj = self._resolve_relative_uri(uri.protocols[0], uri.components[0])
+
+        # core the uri and recurse
+        cored_uri = uri.core():
+
+        if cored_uri:
+            rc = obj.resolve_uri(cored_uri)
+        else:
+            assert type(obj) is Resource
+            rc = ResourceCollection([obj])
+
+        return rc
+
+    def _to_uri_list(self, uri_like):
+        if type(uri) is not list:
+            uri = [uri]
+        ...
+
+    def browse(
+        self,
+        connection: Connection,
+        uri: str | URI | list[str] | list[URI]
+    ) -> ResourceCollection:
         '''
         Analog for Read (CRUD), SELECT (SQL), GET (REST)
         '''
-        pass
+        uris = self._to_uri_list(uri)
+
+        rc = ResourceCollection()
+        for uri in uris:
+            rc.extend(self._resolve_uri(uri))
+
+        return rc
 
 
-class ABCDMedium[R: Resource](BrowsableMedium[R]):
+class WritableMedium[R: Resource](ReadableMedium[R]):
     def append(self, uri: URI[R], resource: R):
         '''
         Analog for Create (CRUD), INSERT (SQL), POST/PUT (REST)

co3/mediums/disk.py

@@ -0,0 +1,6 @@
+from co3 import Medium
+from co3.resources import INode
+
+
+class Disk[INode](Medium):
+    pass

co3/resource.py

@@ -1,10 +1,15 @@
-from typing import Protocol
+from typing import BinaryIO
+
+from co3 import URI, Medium
 
 
 class Resource:
-    def content(self) -> BinaryIO:
+    def __init__(
-        pass
+        self,
+        context: Medium | list[Medium],
+        uri: URI
+    ):
+        self.uri = uri
 
-class SelectableResource(Protocol):
+    def open(self) -> BinaryIO:
-    def select(self, component, *args, **kwargs):
+        pass
-        raise NotImplementedError

co3/resources/inode.py

@@ -0,0 +1,5 @@
+from co3 import Resource
+
+
+class INode(Resource):
+    pass

co3/uri.py

@@ -1,4 +1,4 @@
-from urllib import parse
+from urllib.parse import urlparse
 
 
 class URI:
@@ -13,3 +13,22 @@ class URN(URI):
     def __init__(self, url_str: str):
         self.url_str = url_str
 
+
+class CompositeURI(URI):
+    def __init__(self, url_str: str):
+        url_obj = urlparse(url_str)
+
+        self.protocols = url_obj.scheme.split('+')[::-1]
+        self.components = url_obj.scheme.split('+')[::-1]
+
+    def core(self, layers=1) -> 'CompositeURI':
+        '''
+        "Core" the innermost ``layers`` layers of the composite URI.
+        '''
+        pass
+
+    def shed(self, layers=1) -> 'CompositeURI':
+        '''
+        "Shed" the outermost ``layers`` layers of the composite URI.
+        '''
+        pass

doc/reference/uri.md

@@ -0,0 +1,11 @@
+Quick thoughts and ideals:
+
+- Schemes are compositional, "wrapping" super contexts: `c+b+a://a/b/c`
+- The scheme communicates the target type (above is `c`)
+- URIs can be arbitrarily relative so long as they're resolved in the right contexts.
+  Above, `c+b://b/c` can be resolved in the context of `a://a`
+- URIs are resolved by unwrapping schemes and resolving in to out
+- URL params can apply only to the target type (this is the most consistent and probably
+  not too restrictive)
+- Trajectories from one scheme to another can be inferred from the type hierarchy; there
+  may be many

pyproject.toml

@@ -1,27 +1,25 @@
 [build-system]
-requires = ["setuptools", "wheel", "setuptools-git-versioning>=2.0,<3"]
+requires = ["setuptools", "wheel"]
 build-backend = "setuptools.build_meta"
 
-[tool.setuptools-git-versioning]
-enabled = true
-
 [project]
 name = "co3"
+version = "0.6.3"
 description = "Lightweight Python ORM for hierarchical storage management"
-readme = "README.md"
 requires-python = ">=3.12"
-dynamic = ["version"]
-#license = {file = "LICENSE"}
 authors = [
-  { name="Sam Griesemer", email="samgriesemer+git@gmail.com" },
+  { name="Sam Griesemer", email="git@olog.io" },
 ]
+readme = "README.md"
+license = "MIT"
 keywords = ["database", "orm"]
 classifiers = [
-    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python",
-    "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
     "Development Status :: 3 - Alpha",
+
     "Intended Audience :: Developers",
+    "Intended Audience :: End Users/Desktop",
 ]
 dependencies = [
     "tqdm",
@@ -31,16 +29,23 @@ dependencies = [
     "colorama",
 ]
 
+[project.scripts]
+symconf = "co3.__main__:main"
+
 [project.optional-dependencies]
-tests = ["pytest"]
+dev = [
-docs = [
+    "ipykernel",
+]
+doc = [
+    "furo",
+    "myst-parser",
     "sphinx",
     "sphinx-togglebutton",
     "sphinx-autodoc-typehints",
-    "furo",
-    "myst-parser",
 ]
-jupyter = ["ipykernel"]
+test = [
+    "pytest",
+]
 
 [project.urls]
 Homepage = "https://doc.olog.io/co3"
@@ -48,6 +53,26 @@ Documentation = "https://doc.olog.io/co3"
 Repository = "https://git.olog.io/olog/co3"
 Issues = "https://git.olog.io/olog/co3/issues"
 
+[dependency-groups]
+dev = [
+    "ipykernel",
+]
 
 [tool.setuptools.packages.find]
-include = ["co3*"] # pattern to match package names 
+include = ["co3*"]
+
+[tool.ruff]
+line-length = 79
+
+[tool.ruff.lint]
+select = ["ANN", "E", "F", "UP", "B", "SIM", "I", "C4", "PERF"]
+
+[tool.ruff.lint.isort]
+length-sort = true
+order-by-type = false
+force-sort-within-sections = false
+
+[tool.ruff.format]
+quote-style = "double"
+indent-style = "space"
+docstring-code-format = true

test/co3_medium_demo.py

@@ -0,0 +1,5 @@
+from co3.mediums import Disk
+
+
+disk = Disk('disk:///')
+disk.browse('dir://home')