From 00424a444f984111f0ec5eae11dcafd031f4c9e5 Mon Sep 17 00:00:00 2001
From: Stefano Pigozzi <me@steffo.eu>
Date: Wed, 20 Apr 2022 04:15:10 +0200
Subject: [PATCH] :boom: Yay more changes

---
 .idea/runConfigurations/Sample.xml |   2 +-
 README.md                          |  10 +--
 cfig.iml                           |   1 +
 cfig/__init__.py                   | 110 ---------------------------
 cfig/config.py                     |  86 ++++++++++-----------
 cfig/customtyping.py               |  33 ++++----
 cfig/errors.py                     |   5 ++
 cfig/sample/__init__.py            |   3 +
 cfig/sample/__main__.py            |  63 ----------------
 cfig/sample/definition.py          | 116 +++++++++++++++++++++++++++++
 cfig/sample/usage.py               |  15 ++++
 cfig/sources/base.py               |   4 +
 cfig/sources/env.py                |   4 +
 cfig/sources/envfile.py            |   4 +
 docs/index.rst                     |  85 +++++++++++----------
 docs/reference.rst                 |  38 ++++++++++
 docs/terminology.rst               |  29 ++++++++
 pyproject.toml                     |   2 +-
 18 files changed, 328 insertions(+), 282 deletions(-)
 create mode 100644 cfig/sample/__init__.py
 delete mode 100644 cfig/sample/__main__.py
 create mode 100644 cfig/sample/definition.py
 create mode 100644 cfig/sample/usage.py
 create mode 100644 docs/reference.rst
 create mode 100644 docs/terminology.rst

diff --git a/.idea/runConfigurations/Sample.xml b/.idea/runConfigurations/Sample.xml
index 9bf621d..e8d889c 100644
--- a/.idea/runConfigurations/Sample.xml
+++ b/.idea/runConfigurations/Sample.xml
@@ -13,7 +13,7 @@
     <option name="IS_MODULE_SDK" value="true" />
     <option name="ADD_CONTENT_ROOTS" value="true" />
     <option name="ADD_SOURCE_ROOTS" value="true" />
-    <option name="SCRIPT_NAME" value="cfig.sample" />
+    <option name="SCRIPT_NAME" value="cfig.sample.definition" />
     <option name="PARAMETERS" value="" />
     <option name="SHOW_COMMAND_LINE" value="false" />
     <option name="EMULATE_TERMINAL" value="true" />
diff --git a/README.md b/README.md
index 4a304cf..66d46f6 100644
--- a/README.md
+++ b/README.md
@@ -2,9 +2,7 @@
 
 A configuration manager for Python 
 
-\[ [**Documentation**](https://cfig.readthedocs.io/) | [**PyPI**](https://pypi.org/project/cfig/) \]
-
-## Example
+\[ [**Example**](https://github.com/Steffo99/cfig/tree/main/cfig/sample) | [**Documentation**](https://cfig.readthedocs.io/) | [**PyPI**](https://pypi.org/project/cfig/) \]
 
 ```python
 import cfig
@@ -13,7 +11,7 @@ config = cfig.Configuration()
 
 @config.required()
 def SECRET_KEY(val: str) -> str:
-    """Secret string used to manage tokens."""
+    """Secret string used to manage HTTP session tokens."""
     return val
 
 if __name__ == "__main__":
@@ -28,8 +26,10 @@ print(f"My SECRET_KEY is: {SECRET_KEY}")
 
 ```console
 $ python -m mypackage.mycfig
-=== Configuration ===
+===== Configuration =====
 
 SECRET_KEY    → Required, but not set.
 Secret string used to manage HTTP session tokens.
+
+===== End =====
 ```
diff --git a/cfig.iml b/cfig.iml
index d97dd8b..bcf129d 100644
--- a/cfig.iml
+++ b/cfig.iml
@@ -12,6 +12,7 @@
       <excludeFolder url="file://$MODULE_DIR$/.venv" />
       <excludeFolder url="file://$MODULE_DIR$/.pytest_cache" />
       <excludeFolder url="file://$MODULE_DIR$/cfig/.pytest_cache" />
+      <excludeFolder url="file://$MODULE_DIR$/dist" />
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/cfig/__init__.py b/cfig/__init__.py
index 7be0805..a75d23a 100644
--- a/cfig/__init__.py
+++ b/cfig/__init__.py
@@ -1,113 +1,3 @@
-"""
-This package provides a simple but powerful configuration manager for Python applications.
-
-A goal is to allow easy integration of an application with multiple configuration standards, such as environment
-variables, dotenv files, and Docker Secrets files.
-
-.. code-block:: python
-
-    @config.required()
-    def SECRET_KEY(val: str) -> str:
-        "Secret string used to manage tokens."
-        return val
-
-Another goal is to provide informative error messages to the user who is configuring the application, so that they may
-understand what they are doing wrong and fix it immediately.
-
-.. code-block:: console
-
-    $ python -m cfig.sample
-    === Configuration ===
-
-    SECRET_KEY    → Required, but not set.
-    Secret string used to manage HTTP session tokens.
-
-    HIDDEN_STRING = 'amogus'
-    A string which may be provided to silently print a string to the console.
-
-
-Example
-=======
-
-Ideally, a "config" module should be created, where the programmer defines the possible configuration options of their
-application::
-
-    # Import the cfig library
-    import cfig
-
-    # Create a "Configuration" object
-    config = cfig.Configuration()
-
-    # Define configurable values by wrapping functions with the config decorators
-    # Function name is used by default as the key of the variable to read
-    @config.required()
-    def SECRET_KEY(val: str) -> str:
-        "Secret string used to manage tokens."
-        return val
-
-    @config.required()
-    def ALLOWED_USERS(val: str) -> int:
-        "The maximum number of allowed users in the application."
-        # Values can be processed inside these functions
-        return int(val)
-
-    @config.optional()
-    def ACCEPTED_TERMS_AND_CONDITIONS(val: Optional[str]) -> bool:
-        "To accept T&C, set this to a non-blank string."
-        return val is not None
-
-    # If heavy processing is done inside the function, it may be useful to define the configuration key manually
-    @config.required(key="DATABASE_URI", doc="The URI of the database to be used.")
-    def DATABASE_ENGINE(val: str):
-        return sqlalchemy.create_engine(val)
-
-    if __name__ == "__main__":
-        # If the configuration file is executed as main, handle the call and display a user-friendly CLI interface.
-        config.cli()
-
-Values can later be accessed by the program by importing the configuration file:
-
-.. code-block:: python
-
-    # Import the previously defined file
-    from . import myconfig
-
-    # Function is executed once when the value is first accessed
-    print(f"Maximum allowed users: {myconfig.ALLOWED_USERS}")
-
-    # Advanced objects can be loaded directly from the config
-    Session = sessionmaker(bind=myconfig.DATABASE_ENGINE)
-
-
-Terminology
-===========
-
-In this documentation, the following terms are used:
-
-Key
-    The name of a configuration value, usually in SCREAMING_SNAKE_CASE.
-    For example, ``PATH``, the name of the environment variable.
-
-Value
-    A single non-processed configuration value in :class:`str` form.
-    For example, the raw string value of an environment variable.
-
-Source
-    A possible origin of configuration values, such as the environment, or a file.
-
-Proxy
-    An object used to lazily and transparently resolve and cache values.
-    After resolving a value, it behaves in almost completely the same way as the object it cached.
-
-Resolver
-    A function taking in input a value originating from a source, and emitting in output its processed representation.
-    For example, a resolver may be the :class:`int` class, which converts the value into an integer.
-
-Configuration
-    A collection of proxies.
-
-"""
-
 # noinspection PyUnresolvedReferences
 from .config import *
 # noinspection PyUnresolvedReferences
diff --git a/cfig/config.py b/cfig/config.py
index 085ad28..360dfb5 100644
--- a/cfig/config.py
+++ b/cfig/config.py
@@ -102,44 +102,7 @@ class Configuration:
 
         log.debug("Initialized successfully!")
 
-    def required(self, key: t.Optional[str] = None, doc: t.Optional[str] = None) -> t.Callable[[ct.ResolverRequired], ct.TYPE]:
-        """
-        Mark a function as a resolver for a required configuration value.
-
-        It is a decorator factory, and therefore should be used like so::
-
-            @config.required()
-            def MY_KEY(val: str) -> str:
-                return val
-
-        Key can be overridden manually with the ``key`` parameter.
-
-        Docstring can be overridden manually with the ``doc`` parameter.
-        """
-
-        def _decorator(configurable: ct.ResolverRequired) -> ct.TYPE:
-            nonlocal key
-            nonlocal doc
-
-            if not key:
-                log.debug("Determining key...")
-                key = self._find_resolver_key(configurable)
-                log.debug(f"Key is: {key!r}")
-
-            log.debug("Creating required item...")
-            item: ct.TYPE = self._create_proxy_required(key, configurable)
-            log.debug("Item created successfully!")
-
-            log.debug("Registering item in the configuration...")
-            self.register(key, item, doc if doc is not None else configurable.__doc__)
-            log.debug("Registered successfully!")
-
-            # Return the created item, so it will take the place of the decorated function
-            return item
-
-        return _decorator
-
-    def optional(self, key: t.Optional[str] = None, doc: t.Optional[str] = None) -> t.Callable[[ct.ResolverOptional], ct.TYPE]:
+    def optional(self, key: t.Optional[str] = None, doc: t.Optional[str] = None) -> ct.ProxyOptional:
         """
         Mark a function as a resolver for a required configuration value.
 
@@ -176,8 +139,45 @@ class Configuration:
 
         return _decorator
 
+    def required(self, key: t.Optional[str] = None, doc: t.Optional[str] = None) -> ct.ProxyRequired:
+        """
+        Mark a function as a resolver for a required configuration value.
+
+        It is a decorator factory, and therefore should be used like so::
+
+            @config.required()
+            def MY_KEY(val: str) -> str:
+                return val
+
+        Key can be overridden manually with the ``key`` parameter.
+
+        Docstring can be overridden manually with the ``doc`` parameter.
+        """
+
+        def _decorator(configurable: ct.ResolverRequired) -> ct.TYPE:
+            nonlocal key
+            nonlocal doc
+
+            if not key:
+                log.debug("Determining key...")
+                key = self._find_resolver_key(configurable)
+                log.debug(f"Key is: {key!r}")
+
+            log.debug("Creating required item...")
+            item: ct.TYPE = self._create_proxy_required(key, configurable)
+            log.debug("Item created successfully!")
+
+            log.debug("Registering item in the configuration...")
+            self.register(key, item, doc if doc is not None else configurable.__doc__)
+            log.debug("Registered successfully!")
+
+            # Return the created item, so it will take the place of the decorated function
+            return item
+
+        return _decorator
+
     # noinspection PyMethodMayBeStatic
-    def _find_resolver_key(self, resolver: ct.Resolver) -> str:
+    def _find_resolver_key(self, resolver: ct.ResolverAny) -> str:
         """
         Find the key of a resolver by accessing its ``__name__``.
 
@@ -204,7 +204,7 @@ class Configuration:
             log.debug(f"No values found for {key!r}, returning None.")
             return None
 
-    def _create_proxy_optional(self, key: str, resolver: ct.ResolverOptional) -> lazy_object_proxy.Proxy:
+    def _create_proxy_optional(self, key: str, resolver: ct.ResolverOptional) -> ct.TYPE:
         """
         Create, from a resolver, a proxy tolerating non-specified values.
         """
@@ -234,7 +234,7 @@ class Configuration:
         else:
             raise errors.MissingValueError(key)
 
-    def _create_proxy_required(self, key: str, resolver: ct.ResolverRequired) -> lazy_object_proxy.Proxy:
+    def _create_proxy_required(self, key: str, resolver: ct.ResolverRequired) -> ct.TYPE:
         """
         Create, from a resolver, a proxy intolerant about non-specified values.
         """
@@ -284,7 +284,7 @@ class Configuration:
 
         @click.command()
         def root():
-            click.secho(f"=== Configuration ===", fg="bright_white", bold=True)
+            click.secho(f"===== Configuration =====", fg="bright_white", bold=True)
             click.secho()
 
             key_padding = max(map(lambda k: len(k), self.proxies.keys()))
@@ -321,6 +321,8 @@ class Configuration:
                 click.secho(f"{doc}", fg="white")
                 click.secho()
 
+            click.secho(f"===== End =====", fg="bright_white", bold=True)
+
         return root
 
     def cli(self):
diff --git a/cfig/customtyping.py b/cfig/customtyping.py
index 7bc64a3..6e2e7e0 100644
--- a/cfig/customtyping.py
+++ b/cfig/customtyping.py
@@ -1,29 +1,28 @@
+"""
+This module extends :mod:`typing` with the types used by :mod:`cfig`.
+"""
+
+
 import typing as t
 
+
 TYPE = t.TypeVar("TYPE")
 
 
-class Resolver(t.Protocol):
-    __name__: str
-    __doc__: str
-
-    def __call__(self, val: t.Any) -> TYPE:
-        ...
-
-
-class ResolverRequired(Resolver):
-    def __call__(self, val: str) -> TYPE:
-        ...
-
-
-class ResolverOptional(Resolver):
-    def __call__(self, val: t.Optional[str]) -> TYPE:
-        ...
+ResolverAny = t.Callable[[t.Any], TYPE]
+ResolverRequired = t.Callable[[str], TYPE]
+ResolverOptional = t.Callable[[t.Optional[str]], TYPE]
+ProxyAny = t.Callable[[t.Callable[[t.Any], TYPE]], TYPE]
+ProxyRequired = t.Callable[[t.Callable[[str], TYPE]], TYPE]
+ProxyOptional = t.Callable[[t.Callable[[t.Optional[str]], TYPE]], TYPE]
 
 
 __all__ = (
     "TYPE",
-    "Resolver",
+    "ResolverAny",
     "ResolverRequired",
     "ResolverOptional",
+    "ProxyAny",
+    "ProxyRequired",
+    "ProxyOptional",
 )
diff --git a/cfig/errors.py b/cfig/errors.py
index 880b8e2..3c9f783 100644
--- a/cfig/errors.py
+++ b/cfig/errors.py
@@ -1,3 +1,8 @@
+"""
+This module contains all possible exceptions occurring related to :mod:`cfig`.
+"""
+
+
 class CfigError(Exception):
     """
     Base class for all :mod:`cfig` errors.
diff --git a/cfig/sample/__init__.py b/cfig/sample/__init__.py
new file mode 100644
index 0000000..c44bf9d
--- /dev/null
+++ b/cfig/sample/__init__.py
@@ -0,0 +1,3 @@
+"""
+This module contains an example usage of :mod:`cfig`.
+"""
\ No newline at end of file
diff --git a/cfig/sample/__main__.py b/cfig/sample/__main__.py
deleted file mode 100644
index a97f02a..0000000
--- a/cfig/sample/__main__.py
+++ /dev/null
@@ -1,63 +0,0 @@
-"""
-Sample configuration module using :mod:`cfig`.
-"""
-
-
-import cfig
-import typing
-
-
-config = cfig.Configuration()
-
-
-@config.required()
-def MY_FAVOURITE_STRING(val: str) -> str:
-    """
-    Your favourite string!
-    """
-    return val
-
-
-@config.optional()
-def MY_OPTIONAL_STRING(val: typing.Optional[str]) -> str:
-    """
-    Your favourite string, but optional!
-    """
-    return val or ""
-
-
-@config.required()
-def MY_REQUIRED_INT(val: str) -> int:
-    """
-    Your favourite integer!
-    """
-    try:
-        return int(val)
-    except ValueError:
-        raise cfig.InvalidValueError("Not an int.")
-
-
-@config.required()
-def MY_FAVOURITE_EVEN_INT(val: str) -> int:
-    """
-    Your favourite even number!
-    """
-    try:
-        n = int(val)
-    except ValueError:
-        raise cfig.InvalidValueError("Not an int.")
-    if n % 2:
-        raise cfig.InvalidValueError("Not an even int.")
-    return n
-
-
-@config.required(key="KEY_NAME")
-def VAR_NAME(val: str) -> str:
-    """
-    This config value looks for a key in the configuration sources but is available at a different key to the programmer.
-    """
-    return val
-
-
-if __name__ == "__main__":
-    config.cli()
diff --git a/cfig/sample/definition.py b/cfig/sample/definition.py
new file mode 100644
index 0000000..1651d17
--- /dev/null
+++ b/cfig/sample/definition.py
@@ -0,0 +1,116 @@
+"""
+This module contains the definition of an example :class:`~cfig.config.Configuration` using :mod:`cfig`.
+"""
+
+# Import the cfig module, so it may be used in the file
+import cfig
+# Alias the typing module as t, so it can be used faster
+import typing as t
+
+# Create a new configuration using the default sources:
+# - environment variables: EXAMPLE_VALUE
+# - contents of the files specified in environment variables whose keys are suffixed by _FILE: EXAMPLE_VALUE_FILE
+config = cfig.Configuration()
+
+
+# Create a new proxy for a required configuration value
+# It will behave in almost the same way as the object it is proxying
+# The main differences are that:
+# - "is" comparisions won't work: <Proxy None> is not None
+# - some additional magic methods will be available, but you don't need to bother with them
+@config.required()
+def EXAMPLE_STRING(val: str) -> str:
+    # The proxy is a function whose name will be used as key to access its value
+    # Since this function is named EXAMPLE_STRING, and we are using the default sources, it will try to access in order:
+    # - the EXAMPLE_STRING environment variable
+    # - the file at the path specified in the EXAMPLE_STRING_FILE environment variable
+
+    # The docstring of the function will be used to inform the user of what should be in this configuration option.
+    """
+    An example string: since this is an example, you can enter anything here, as it won't be used!
+    It will have to be *something*, though.
+    """
+
+    # The code of the function will be used to process the "raw" value obtained from the sources
+    # Since we do not want to alter the obtained value any further, we'll just return it
+    return val
+
+
+# Since the EXAMPLE_STRING proxy was defined as required, it will raise an error if no value is found at any source.
+# Optional proxies exist, though!
+@config.optional()
+def EXAMPLE_NUMBER(val: t.Optional[str]) -> int:
+    """
+    An example number: again, since this is an example, it will not matter what value you will set it to.
+    If you do not set it to anything, it will default to 0.
+    """
+
+    # Let's default to 0 in case the user doesn't pass any value
+    if val is None:
+        return 0
+
+    # Otherwise, let's try to parse the value as an int
+    try:
+        return int(val)
+    # It's possible that the user entered an invalid number, though, so let's handle that case
+    except ValueError:
+        # User errors are be handled explicitly so that the user knows it's not the programmer's fault
+        raise cfig.InvalidValueError("Not an int.")
+
+
+# And that's it!
+# Let's make some more proxies as examples with no comments inbetween
+# So you can have an easier idea of how cfig configs are made
+
+
+@config.required()
+def TELEGRAM_BOT_TOKEN(val: t.Optional[str]) -> str:
+    """
+    The token of the Telegram bot to login as.
+    Obtain one at https://t.me/BotFather !
+    """
+
+    try:
+        _id, _proper_token = val.split(":", 1)
+    except ValueError:
+        raise cfig.InvalidValueError("Not a Telegram bot token.")
+
+    return val
+
+
+@config.required()
+def DISCORD_CLIENT_SECRET(val: t.Optional[str]) -> str:
+    """
+    The OAuth2 client secret of the Discord application to use.
+    Obtain one at https://discord.com/developers/applications !
+    """
+
+    return val
+
+
+# Proxies are lazily evaluated and executed only once, so you may use them to perform slower synchronous tasks
+# For example, connecting to a database!
+# They may be used even in global contexts such as in Flask or FastAPI apps without compromising their importability!
+
+
+# Let's make a fake create_engine function so that I don't have to add sqlalchemy to cfig's dependencies
+def create_engine(uri):
+    ...
+
+
+# Since the user inputs an URI, while we are creating a database
+# We might want to use separate names for the "user-side" and the "programmer-side"
+# We can specify the "user-side" name in the decorator
+# And we can additionally specify the docstring
+@config.required(key="DATABASE_URI", doc="The URI of the database to use.")
+def DATABASE_ENGINE(val: str):
+    return create_engine(uri=val)
+
+
+# Finally, let's configure the config CLI
+# Let's run the CLI only if this specific script is explicitly run
+if __name__ == "__main__":
+    # Then, pass the control to click
+    # Argv will be automatically read and handled
+    config.cli()
+    # Please note that this will raise an error if the "cli" extra is not installed!
diff --git a/cfig/sample/usage.py b/cfig/sample/usage.py
new file mode 100644
index 0000000..a02dc1b
--- /dev/null
+++ b/cfig/sample/usage.py
@@ -0,0 +1,15 @@
+"""
+This module contains an example of how to use the values defined in a cfig definition module.
+"""
+
+from .definition import EXAMPLE_STRING, EXAMPLE_NUMBER, DATABASE_ENGINE
+
+
+if __name__ == "__main__":
+    print(f"Hey! The example string you entered was {EXAMPLE_STRING}!")
+
+    # IDEA seems to be a bit confused here
+    # noinspection PyTypeChecker
+    print(f"And the square of the example number was {EXAMPLE_NUMBER ** 2}!")
+
+    print(f"We should do something with that {DATABASE_ENGINE} we created...")
diff --git a/cfig/sources/base.py b/cfig/sources/base.py
index bf9dbb6..26a857a 100644
--- a/cfig/sources/base.py
+++ b/cfig/sources/base.py
@@ -1,3 +1,7 @@
+"""
+This module defines the :class:`.Source` abstract class.
+"""
+
 import abc
 import typing as t
 
diff --git a/cfig/sources/env.py b/cfig/sources/env.py
index fb3ac87..4fc716a 100644
--- a/cfig/sources/env.py
+++ b/cfig/sources/env.py
@@ -1,3 +1,7 @@
+"""
+This module defines the :class:`.EnvironmentSource` :class:`~cfig.sources.base.Source`.
+"""
+
 import os
 import typing as t
 from cfig.sources.base import Source
diff --git a/cfig/sources/envfile.py b/cfig/sources/envfile.py
index 77c8ef5..931bac7 100644
--- a/cfig/sources/envfile.py
+++ b/cfig/sources/envfile.py
@@ -1,3 +1,7 @@
+"""
+This module defines the :class:`.EnvironmentFileSource` :class:`~cfig.sources.base.Source`.
+"""
+
 import typing as t
 from cfig.sources.env import EnvironmentSource
 
diff --git a/docs/index.rst b/docs/index.rst
index 7f97416..f919f09 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -2,58 +2,57 @@
 cfig
 ####
 
-
-.. automodule:: cfig
+The :mod:`cfig` package provides a simple but powerful configuration manager for Python applications.
 
 
-Classes
+Goals
+=====
+
+A goal is to allow easy integration of an application with multiple configuration standards, such as environment
+variables, dotenv files, and Docker Secrets files.
+
+.. code-block:: python
+
+    @config.required()
+    def SECRET_KEY(val: str) -> str:
+        "Secret string used to manage tokens."
+        return val
+
+Another goal is to provide informative error messages to the user who is configuring the application, so that they may
+understand what they are doing wrong and fix it immediately.
+
+.. code-block:: console
+
+    $ python -m cfig.sample
+    === Configuration ===
+
+    SECRET_KEY    → Required, but not set.
+    Secret string used to manage HTTP session tokens.
+
+    HIDDEN_STRING = 'amogus'
+    A string which may be provided to silently print a string to the console.
+
+Finally, the last goal is having useful typing for developers using :mod:`cfig`, allowing them to make full use of the
+features of their IDEs.
+
+.. image:: example-typing.png
+
+
+Example
 =======
 
-:mod:`cfig.config`
-------------------
-
-.. automodule:: cfig.config
+If you'd like to learn how to use :mod:`cfig` hands-on,
+read `the source code of the cfig.sample module <https://github.com/Steffo99/cfig/tree/main/cfig/sample>`_!
 
 
-:mod:`cfig.errors`
-------------------
-
-.. automodule:: cfig.errors
-    :show-inheritance:
-
-
-Built-in sources
-----------------
-
-:mod:`cfig.sources.base`
-~~~~~~~~~~~~~~~~~~~~~~~~
-
-.. automodule:: cfig.sources.base
-
-
-:mod:`cfig.sources.env`
-~~~~~~~~~~~~~~~~~~~~~~~
-
-.. automodule:: cfig.sources.env
-    :show-inheritance:
-
-
-:mod:`cfig.sources.envfile`
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-.. automodule:: cfig.sources.envfile
-    :show-inheritance:
-
-
-Table of contents
-=================
-
-.. error::
-
-    I think I broke Sphinx, since the table of contents doesn't seem to show up...
+Pages of this documentation
+===========================
 
 .. toctree::
 
+    terminology
+    reference
+
 
 Other tables and links
 ======================
diff --git a/docs/reference.rst b/docs/reference.rst
new file mode 100644
index 0000000..897cce5
--- /dev/null
+++ b/docs/reference.rst
@@ -0,0 +1,38 @@
+#############
+API reference
+#############
+
+.. automodule:: cfig
+
+
+:mod:`cfig.config`
+------------------
+
+.. automodule:: cfig.config
+
+
+:mod:`cfig.errors`
+------------------
+
+.. automodule:: cfig.errors
+    :show-inheritance:
+
+
+:mod:`cfig.sources.base`
+------------------------
+
+.. automodule:: cfig.sources.base
+
+
+:mod:`cfig.sources.env`
+-----------------------
+
+.. automodule:: cfig.sources.env
+    :show-inheritance:
+
+
+:mod:`cfig.sources.envfile`
+---------------------------
+
+.. automodule:: cfig.sources.envfile
+    :show-inheritance:
diff --git a/docs/terminology.rst b/docs/terminology.rst
new file mode 100644
index 0000000..1b2bcbc
--- /dev/null
+++ b/docs/terminology.rst
@@ -0,0 +1,29 @@
+###########
+Terminology
+###########
+
+In this documentation, the following terms are used:
+
+.. glossary::
+
+    Key
+        The name of a configuration value, usually in SCREAMING_SNAKE_CASE.
+        For example, ``PATH``, the name of the environment variable.
+
+    Value
+        A single non-processed configuration value in :class:`str` form.
+        For example, the raw string value of an environment variable.
+
+    Source
+        A possible origin of configuration values, such as the environment, or a file.
+
+    Proxy
+        An object used to lazily and transparently resolve and cache values.
+        After resolving a value, it behaves in almost completely the same way as the object it cached.
+
+    Resolver
+        A function taking in input a value originating from a source, and emitting in output its processed representation.
+        For example, a resolver may be the :class:`int` class, which converts the value into an integer.
+
+    Configuration
+        A collection of proxies.
diff --git a/pyproject.toml b/pyproject.toml
index 0cfb960..45c3660 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "cfig"
-version = "0.1.0"
+version = "0.2.0"
 description = "A configuration manager for Python"
 authors = ["Stefano Pigozzi <me@steffo.eu>"]
 license = "MIT"