chore: clean up casting

ibis/backends/base/sql/alchemy/registry.py

@@ -163,18 +163,18 @@ def _exists_subquery(t, op):
 def _cast(t, op):
     arg = op.arg
     typ = op.to
+    arg_dtype = arg.output_dtype
 
     sa_arg = t.translate(arg)
-    sa_type = t.get_sqla_type(typ)
 
-    if isinstance(arg, ir.CategoryValue) and typ == dt.int32:
+    if arg_dtype.is_category() and typ.is_int32():
         return sa_arg
 
     # specialize going from an integer type to a timestamp
-    if arg.output_dtype.is_integer() and isinstance(sa_type, sa.DateTime):
+    if arg_dtype.is_integer() and typ.is_timestamp():
         return t.integer_to_timestamp(sa_arg)
 
-    if arg.output_dtype.is_binary() and typ.is_string():
+    if arg_dtype.is_binary() and typ.is_string():
         return sa.func.encode(sa_arg, 'escape')
 
     if typ.is_binary():
@@ -185,10 +185,7 @@ def _cast(t, op):
     if typ.is_json() and not t.native_json_type:
         return sa_arg
 
-    ignore_cast_types = t._ignore_cast_types
-    if ignore_cast_types and isinstance(typ, ignore_cast_types):
-        return sa_arg
-    return sa.cast(sa_arg, sa_type)
+    return t.cast(sa_arg, typ)
 
 
 def _contains(func):

ibis/backends/base/sql/alchemy/translator.py

@@ -45,7 +45,6 @@ class AlchemyExprTranslator(ExprTranslator):
     integer_to_timestamp = sa.func.to_timestamp
     native_json_type = True
     _always_quote_columns = False
-    _ignore_cast_types = ()
 
     _require_order_by = (
         ops.DenseRank,
@@ -89,6 +88,9 @@ def _reduction(self, sa_func, op):
 
         return sa_func(*sa_args)
 
+    def cast(self, sa_expr, ibis_type: dt.DataType):
+        return sa.cast(sa_expr, self.get_sqla_type(ibis_type))
+
 
 rewrites = AlchemyExprTranslator.rewrites
 

ibis/backends/snowflake/__init__.py

@@ -40,7 +40,11 @@ class SnowflakeExprTranslator(AlchemyExprTranslator):
         ops.Lead,
     )
     _require_order_by = (*AlchemyExprTranslator._require_order_by, ops.Reduction)
-    _ignore_cast_types = (dt.Map, dt.Array)
+
+    def cast(self, sa_expr, ibis_type: dt.DataType):
+        if ibis_type.is_array() or ibis_type.is_map() or ibis_type.is_struct():
+            return sa.type_coerce(sa_expr, self.get_sqla_type(ibis_type))
+        return super().cast(sa_expr, ibis_type)
 
 
 class SnowflakeCompiler(AlchemyCompiler):