def scalar_type_to_python_type(
stype: s_types.Type,
schema: s_schema.Schema,
) -> type:
for basetype_name, pytype in typemap.items():
basetype = schema.get(basetype_name, type=s_obj.InheritingObject)
if stype.issubclass(schema, basetype):
return pytype
if stype.is_enum(schema):
return str
raise UnsupportedExpressionError(
f'{stype.get_displayname(schema)} is not representable in Python')
def compile_cast(
ir_expr: Union[irast.Set, irast.Expr],
new_stype: s_types.Type,
*,
srcctx: Optional[parsing.ParserContext],
ctx: context.ContextLevel,
cardinality_mod: Optional[qlast.CardinalityModifier] = None
) -> irast.Set:
if isinstance(ir_expr, irast.EmptySet):
# For the common case of casting an empty set, we simply
# generate a new EmptySet node of the requested type.
return setgen.new_empty_set(
stype=new_stype,
alias=ir_expr.path_id.target_name_hint.name,
ctx=ctx,
srcctx=ir_expr.context)
elif irutils.is_untyped_empty_array_expr(ir_expr):
# Ditto for empty arrays.
new_typeref = typegen.type_to_typeref(new_stype, ctx.env)
return setgen.ensure_set(irast.Array(elements=[], typeref=new_typeref),
ctx=ctx)
ir_set = setgen.ensure_set(ir_expr, ctx=ctx)
orig_stype = setgen.get_set_type(ir_set, ctx=ctx)
if (orig_stype == new_stype
and cardinality_mod is not qlast.CardinalityModifier.Required):
return ir_set
elif orig_stype.is_object_type() and new_stype.is_object_type():
# Object types cannot be cast between themselves,
# as cast is a _constructor_ operation, and the only
# valid way to construct an object is to INSERT it.
raise errors.QueryError(
f'cannot cast object type '
f'{orig_stype.get_displayname(ctx.env.schema)!r} '
f'to {new_stype.get_displayname(ctx.env.schema)!r}, use '
f'`...[IS {new_stype.get_displayname(ctx.env.schema)}]` instead',
context=srcctx)
if isinstance(ir_set.expr, irast.Array):
return _cast_array_literal(ir_set,
orig_stype,
new_stype,
srcctx=srcctx,
ctx=ctx)
elif orig_stype.is_tuple(ctx.env.schema):
return _cast_tuple(ir_set,
orig_stype,
new_stype,
srcctx=srcctx,
ctx=ctx)
elif orig_stype.issubclass(ctx.env.schema, new_stype):
# The new type is a supertype of the old type,
# and is always a wider domain, so we simply reassign
# the stype.
return _inheritance_cast_to_ir(ir_set,
orig_stype,
new_stype,
cardinality_mod=cardinality_mod,
ctx=ctx)
elif new_stype.issubclass(ctx.env.schema, orig_stype):
# The new type is a subtype, so may potentially have
# a more restrictive domain, generate a cast call.
return _inheritance_cast_to_ir(ir_set,
orig_stype,
new_stype,
cardinality_mod=cardinality_mod,
ctx=ctx)
elif orig_stype.is_array():
return _cast_array(ir_set,
orig_stype,
new_stype,
srcctx=srcctx,
ctx=ctx)
else:
json_t = ctx.env.get_track_schema_type('std::json')
if (new_stype.issubclass(ctx.env.schema, json_t)
and ir_set.path_id.is_objtype_path()):
# JSON casts of objects are special: we want the full shape
# and not just an identity.
with ctx.new() as subctx:
subctx.implicit_id_in_shapes = False
subctx.implicit_tid_in_shapes = False
viewgen.compile_view_shapes(ir_set, ctx=subctx)
elif (orig_stype.issubclass(ctx.env.schema, json_t)
and new_stype.is_enum(ctx.env.schema)):
# Casts from json to enums need some special handling
# here, where we have access to the enum type. Just turn
# it into json->str and str->enum.
str_typ = ctx.env.get_track_schema_type('std::str')
str_ir = compile_cast(ir_expr, str_typ, srcctx=srcctx, ctx=ctx)
return compile_cast(str_ir,
new_stype,
cardinality_mod=cardinality_mod,
srcctx=srcctx,
ctx=ctx)
elif (orig_stype.issubclass(ctx.env.schema, json_t)
and isinstance(new_stype, s_types.Array)
and not new_stype.get_subtypes(ctx.env.schema)[0].issubclass(
ctx.env.schema, json_t)):
# Turn casts from json->array<T> into json->array<json>
# and array<json>->array<T>.
ctx.env.schema, json_array_typ = s_types.Array.from_subtypes(
ctx.env.schema, [json_t])
json_array_ir = compile_cast(ir_expr,
json_array_typ,
srcctx=srcctx,
ctx=ctx)
return compile_cast(json_array_ir,
new_stype,
cardinality_mod=cardinality_mod,
srcctx=srcctx,
ctx=ctx)
elif (orig_stype.issubclass(ctx.env.schema, json_t)
and isinstance(new_stype, s_types.Tuple)):
return _cast_json_to_tuple(ir_set,
orig_stype,
new_stype,
srcctx=srcctx,
ctx=ctx)
return _compile_cast(ir_expr,
orig_stype,
new_stype,
cardinality_mod=cardinality_mod,
srcctx=srcctx,
ctx=ctx)
