Support for complex params (#30)

* Support for complex params

* More tests

* Added better parsing

* nit

* e2e tests

* nit

* Updated poetry.lock

* poetry changes

* more tests

Author: jprakash-db

poetry.lock

@@ -1,4 +1,10 @@
 from databricks.sqlalchemy.base import DatabricksDialect
-from databricks.sqlalchemy._types import TINYINT, TIMESTAMP, TIMESTAMP_NTZ
+from databricks.sqlalchemy._types import (
+    TINYINT,
+    TIMESTAMP,
+    TIMESTAMP_NTZ,
+    DatabricksArray,
+    DatabricksMap,
+)
 
-__all__ = ["TINYINT", "TIMESTAMP", "TIMESTAMP_NTZ"]
+__all__ = ["TINYINT", "TIMESTAMP", "TIMESTAMP_NTZ", "DatabricksArray", "DatabricksMap"]

src/databricks/sqlalchemy/__init__.py

@@ -5,6 +5,7 @@
 import sqlalchemy
 from sqlalchemy.engine.interfaces import Dialect
 from sqlalchemy.ext.compiler import compiles
+from sqlalchemy.types import TypeDecorator, UserDefinedType
 
 from databricks.sql.utils import ParamEscaper
 
@@ -26,6 +27,11 @@ def process_literal_param_hack(value: Any):
     return value
 
 
+def identity_processor(value):
+    """This method returns the value itself, when no other processor is provided"""
+    return value
+
+
 @compiles(sqlalchemy.types.Enum, "databricks")
 @compiles(sqlalchemy.types.String, "databricks")
 @compiles(sqlalchemy.types.Text, "databricks")
@@ -321,3 +327,73 @@ class TINYINT(sqlalchemy.types.TypeDecorator):
 @compiles(TINYINT, "databricks")
 def compile_tinyint(type_, compiler, **kw):
     return "TINYINT"
+
+
+class DatabricksArray(UserDefinedType):
+    """
+    A custom array type that can wrap any other SQLAlchemy type.
+
+    Examples:
+        DatabricksArray(String)         -> ARRAY<STRING>
+        DatabricksArray(Integer)        -> ARRAY<INT>
+        DatabricksArray(CustomType)     -> ARRAY<CUSTOM_TYPE>
+    """
+
+    def __init__(self, item_type):
+        self.item_type = item_type() if isinstance(item_type, type) else item_type
+
+    def bind_processor(self, dialect):
+        item_processor = self.item_type.bind_processor(dialect)
+        if item_processor is None:
+            item_processor = identity_processor
+
+        def process(value):
+            return [item_processor(val) for val in value]
+
+        return process
+
+
+@compiles(DatabricksArray, "databricks")
+def compile_databricks_array(type_, compiler, **kw):
+    inner = compiler.process(type_.item_type, **kw)
+
+    return f"ARRAY<{inner}>"
+
+
+class DatabricksMap(UserDefinedType):
+    """
+    A custom map type that can wrap any other SQLAlchemy types for both key and value.
+
+    Examples:
+        DatabricksMap(String, String)         -> MAP<STRING,STRING>
+        DatabricksMap(Integer, String)        -> MAP<INT,STRING>
+        DatabricksMap(String, DatabricksArray(Integer)) -> MAP<STRING,ARRAY<INT>>
+    """
+
+    def __init__(self, key_type, value_type):
+        self.key_type = key_type() if isinstance(key_type, type) else key_type
+        self.value_type = value_type() if isinstance(value_type, type) else value_type
+
+    def bind_processor(self, dialect):
+        key_processor = self.key_type.bind_processor(dialect)
+        value_processor = self.value_type.bind_processor(dialect)
+
+        if key_processor is None:
+            key_processor = identity_processor
+        if value_processor is None:
+            value_processor = identity_processor
+
+        def process(value):
+            return {
+                key_processor(key): value_processor(value)
+                for key, value in value.items()
+            }
+
+        return process
+
+
+@compiles(DatabricksMap, "databricks")
+def compile_databricks_map(type_, compiler, **kw):
+    key_type = compiler.process(type_.key_type, **kw)
+    value_type = compiler.process(type_.value_type, **kw)
+    return f"MAP<{key_type},{value_type}>"