move type system docs content from old location (flyteorg#206)

* move type system docs content from old location

Signed-off-by: cosmicBboy <niels.bantilan@gmail.com>

* Update README.rst

Signed-off-by: cosmicBboy <niels.bantilan@gmail.com>

Co-authored-by: SandraGH5 <80421934+SandraGH5@users.noreply.github.com>

cookbook/type_system/README.rst

@@ -1,8 +1,143 @@
 .. _type system:
 
 Type System
--------------------------------------------------------------------------------------
+------------
 
-.. NOTE::
+.. currentmodule:: core
 
-    Coming soon 🛠
+.. _flyte_type_system:
+
+Flyte is a data-aware DAG scheduling system. The Graph itself is derived automatically from the flow of data and this
+closely resembles how a functional programming language passes data between methods.
+
+Data awareness is powered by Flyte's own type system, which closely maps most programming languages. These types are
+what power Flyte's magic of:
+
+- Data lineage
+- Memoization
+- Auto parallelization
+- Simplifying access to data
+- Auto generated CLI and Launch UI
+
+It also opens up possibilities of future optimizations.
+
+.. _flytekit_to_flyte_type_mapping:
+
+Mapping of Types between Python and Flyte - using Flytekit
+###########################################################
+
+FlyteKit automatically maps Python types to Flyte types. This section provides details of the mappings, but for the most
+part you can skip this section, as almost all of Python types are mapped automatically.
+
+The following table provides a quick overview of how types are converted from the type-hints (python native) to Flyte-understood, cross-language types.
+
+.. list-table:: Supported Python types and mapping to underlying Flyte Type
+   :widths: auto
+   :header-rows: 1
+
+   * - Python Type
+     - Flyte Type
+     - Conversion
+     - Comment
+   * - int
+     - Integer
+     - Automatic
+     - just use python 3 type hints
+   * - float
+     - Float
+     - Automatic
+     - just use python 3 type hints
+   * - str
+     - String
+     - Automatic
+     - just use python 3 type hints
+   * - bool
+     - Boolean
+     - Automatic
+     - just use python 3 type hints
+   * - bytes/bytearray
+     - binary
+     - Not Supported
+     - Let us know if this is an interesting usecase that you can currently support using your own transformers.
+   * - complex
+     - NA
+     - Not Supported
+     - Let us know if this is an interesting usecase that you can currently support using your own transformers.
+   * - datetime.timedelta
+     - Duration
+     - Automatic
+     - just use python 3 type hints
+   * - datetime.datetime
+     - Datetime
+     - Automatic
+     - just use python 3 type hints
+   * - Univariate List / typing.List
+     - Collection [ type ]
+     - Automatic
+     - Use python 3 type hints e.g ``typing.List[T], where T can be one of the other supported types in the table``
+   * - file / file-like / os.PathLike / flytekit.types.file.FlyteFile
+     - Blob - Single
+     - Automatic
+     - Use python 3 type hints. if using ``file / os.PathLike`` objects then, Flyte will default to binary protocol for the file. If using FlyteFile["protocol"], it is assumed that the file is in the specified protocol. e.g. "jpg", "png", "hdf5" etc
+   * - Directory / flytekit.types.directory.FlyteDirectory
+     - Blob - MultiPart
+     - Automatic
+     - Use python 3 type hints. If using FlyteDirectory["protocol"] it is assumed that all the files are of the specified protocol
+   * - Typed dictionary with str key - typing.Dict[str, V]
+     - Map[str, V]
+     - Automatic
+     - Use python 3 type hints e.g ``typing.Dict[str, V], where V can be one of the other supported types in the table even another Dictionary (nested)``
+   * - Untyped dictionary - dict
+     - JSON (struct.pb)
+     - Automatic
+     - Use python 3 type hints e.g ``dict``, it will be assumed that we can convert the dict to json. This may not always be possible and will cause a RuntimeError
+   * - Dataclasses ``@dataclass``
+     - Struct
+     - Automatic
+     - Use python 3 type hints. The class should be a pure value class and should be annotated with ``@dataclass and @dataclass_json``.
+   * - pandas.DataFrame
+     - Schema
+     - Automatic
+     - Use python 3 type hints. Pandas column types are not preserved
+   * - pyspark.DataFrame
+     - Schema
+     - Automatic
+     - Use python 3 type hints. Column types are not preserved. Install ``flytekitplugins-spark`` plugin using pip
+   * - FlyteSchema[Columns, format]
+     - Schema
+     - Automatic
+     - Use python 3 type hints. Column types are not preserved
+   * - User defined types
+     - Any
+     - Custom Transformers
+     - Use python 3 type hints, but need to provide custom transformers. Refer to :ref:`advanced_custom_types`.
+
+
+.. prompt:: bash
+
+    flyte-cli -h localhost:30081 -i list-launch-plan-versions -p flytesnacks -d development | grep PrimitiveDemoWorkflow
+    flyte-cli -h localhost:30081 -i execute-launch-plan -p flytesnacks -d development -u <urn> -r user -- x=10 y=10.0 s="Hello" b=True
+
+To retrieve the right LaunchPlan Urn:
+
+.. prompt:: bash
+
+    flyte-cli -h localhost:30081 -i list-launch-plan-versions -p flytesnacks -d development | grep TimeDemoWorkflow
+
+Then take the URN and plug here
+
+.. prompt:: bash
+
+    flyte-cli -h localhost:30081 -i execute-launch-plan -p flytesnacks -d development -u <urn> -r kumare -- dt=20200707T00:00Z duration=10H
+
+The CLI accepts *datetime* and *duration* fields in [RFC3339](https://tools.ietf.org/html/rfc3339 ) formats, which is
+usually of the form **YYYYMMDDTHH:MM:SSZ** ``(z -> timezone)``. Duration is of the format **10H** (for 10 hours) or **10S**
+or **2D** (days etc)
+
+.. prompt:: bash
+
+    flyte-cli -p flytesnacks \
+        -d development execute-launch-plan \
+        -u lp:flytesnacks:development:types.generic.GenericDemoWorkflow:version \
+        -r demo \
+        -- a='{"a": "hello", "b": "how are you", "c": ["array"], "d": {"nested": "value"}}'