def _cast_json_to_tuple(
ir_set: irast.Set,
orig_stype: s_types.Type,
new_stype: s_types.Tuple,
cardinality_mod: Optional[qlast.CardinalityModifier],
*,
srcctx: Optional[parsing.ParserContext],
ctx: context.ContextLevel) -> irast.Set:
with ctx.new() as subctx:
subctx.anchors = subctx.anchors.copy()
source_path = subctx.create_anchor(ir_set, 'a')
# Top-level json->tuple casts should produce an empty set on
# null inputs, but error on missing fields or null
# subelements, so filter out json nulls directly here to
# distinguish those cases.
if cardinality_mod != qlast.CardinalityModifier.Required:
pathctx.register_set_in_scope(ir_set, ctx=subctx)
check = qlast.FunctionCall(
func=('__std__', 'json_typeof'), args=[source_path]
)
filtered = qlast.SelectQuery(
result=source_path,
where=qlast.BinOp(
left=check,
op='!=',
right=qlast.StringConstant(value='null'),
)
)
filtered_ir = dispatch.compile(filtered, ctx=subctx)
source_path = subctx.create_anchor(filtered_ir, 'a')
# TODO: try using jsonb_to_record instead of a bunch of
# json_get calls and see if that is faster.
elements = []
for new_el_name, new_st in new_stype.iter_subtypes(ctx.env.schema):
val_e = qlast.FunctionCall(
func=('__std__', 'json_get'),
args=[
source_path,
qlast.StringConstant(value=new_el_name),
],
)
val = dispatch.compile(val_e, ctx=subctx)
val = compile_cast(
val, new_st,
cardinality_mod=qlast.CardinalityModifier.Required,
ctx=subctx, srcctx=srcctx)
elements.append(irast.TupleElement(name=new_el_name, val=val))
return setgen.new_tuple_set(
elements,
named=new_stype.is_named(ctx.env.schema),
ctx=subctx,
)
def eta_expand_tuple(
path: qlast.Path,
stype: s_types.Tuple,
*,
ctx: context.ContextLevel,
) -> qlast.Expr:
"""η-expansion of tuples
η-expansion of tuple types is straightforward and traditional:
EXPAND(tuple<t, s>, p) = (EXPAND(t, p.0), EXPAND(s, p.1))
is the case for pairs. n-ary and named cases are generalized in the
obvious way.
The one exception is that the expansion of the empty tuple type is
`p` and not `()`, to ensure that the path appears in the output.
"""
if not stype.get_subtypes(ctx.env.schema):
return path
els = [
qlast.TupleElement(
name=qlast.ObjectRef(name=name),
val=eta_expand(astutils.extend_path(path, name), subtype, ctx=ctx),
) for name, subtype in stype.iter_subtypes(ctx.env.schema)
]
if stype.is_named(ctx.env.schema):
return qlast.NamedTuple(elements=els)
else:
return qlast.Tuple(elements=[el.val for el in els])
def _cast_json_to_tuple(ir_set: irast.Set, orig_stype: s_types.Type,
new_stype: s_types.Tuple, *,
srcctx: Optional[parsing.ParserContext],
ctx: context.ContextLevel) -> irast.Set:
with ctx.new() as subctx:
subctx.anchors = subctx.anchors.copy()
source_alias = subctx.aliases.get('a')
subctx.anchors[source_alias] = ir_set
# TODO: try using jsonb_to_record instead of a bunch of
# json_get calls and see if that is faster.
elements = []
for new_el_name, new_st in new_stype.iter_subtypes(ctx.env.schema):
val_e = qlast.FunctionCall(
func=('__std__', 'json_get'),
args=[
qlast.Path(steps=[qlast.ObjectRef(name=source_alias)]),
qlast.StringConstant(value=new_el_name),
],
)
val = dispatch.compile(val_e, ctx=subctx)
val = compile_cast(
val,
new_st,
cardinality_mod=qlast.CardinalityModifier.Required,
ctx=subctx,
srcctx=srcctx)
elements.append(irast.TupleElement(name=new_el_name, val=val))
return setgen.new_tuple_set(
elements,
named=new_stype.is_named(ctx.env.schema),
ctx=subctx,
)