Add type intersection expressions (#948)

Given a schema:
```edgeql
type Inh_A { a: int64; };
type Inh_B { b: int64; };
type Inh_C { c: int64; };
type Inh_AB extending Inh_A, Inh_B { ab: int64; };
type Inh_AC extending Inh_A, Inh_C { ac: int64; };
type Inh_BC extending Inh_B, Inh_C { bc: int64; };
type Inh_ABC extending Inh_A, Inh_B, Inh_C { abc: int64; };
type Inh_AB_AC extending Inh_AB, Inh_AC { ab_ac: int64; };
```

Supports queries such as:
```py
client.query(
    default.Inh_A.when_type(default.Inh_B).is_(default.Inh_C)
)
client.query(
    default.Inh_AB.select(a=lambda x: x.is_(default.Inh_C).c)
)
```

Author: dnwpark

gel/_internal/_codegen/_models/_pydantic.py

@@ -2909,15 +2909,15 @@ def _write_prefix_op_method_node_ctor(
     ) -> None:
         """Generate the query node constructor for a prefix operator method.
 
-        Creates the code that builds a PrefixOp query node for unary operator
+        Creates the code that builds a UnaryOp query node for unary operator
         methods like __neg__. The operator is applied to 'self' as the
         operand.
 
         Args:
             op: The operator reflection object containing metadata
         """
         op_name = op.schemapath.name
-        node_cls = self.import_name(BASE_IMPL, "PrefixOp")
+        node_cls = self.import_name(BASE_IMPL, "UnaryOp")
 
         args = [
             "expr=self",  # The operand is always 'self' for method calls
@@ -2967,15 +2967,15 @@ def _write_prefix_op_func_node_ctor(
     ) -> None:
         """Generate the query node constructor for a prefix operator function.
 
-        Creates the code that builds a PrefixOp query node for unary operator
+        Creates the code that builds a UnaryOp query node for unary operator
         functions. Unlike method versions, this takes the operand from function
         arguments and applies special type casting for tuple parameters.
 
         Args:
             op: The operator reflection object containing metadata
         """
         op_name = op.schemapath.name
-        node_cls = self.import_name(BASE_IMPL, "PrefixOp")
+        node_cls = self.import_name(BASE_IMPL, "UnaryOp")
         expr_compat = self.import_name(BASE_IMPL, "ExprCompatible")
         cast_ = self.import_name("typing", "cast")
 

gel/_internal/_qb/__init__.py

@@ -11,6 +11,7 @@
     AbstractFieldDescriptor,
     Expr,
     PathPrefix,
+    PathTypeIntersectionPrefix,
     Scope,
     ScopeContext,
     Stmt,
@@ -36,14 +37,14 @@
     IntLiteral,
     Limit,
     Literal,
+    ObjectWhenType,
     Offset,
     OrderBy,
     OrderByElem,
     OrderByExpr,
     OrderDirection,
     OrderEmptyDirection,
     Path,
-    PrefixOp,
     SchemaSet,
     SelectStmt,
     SetLiteral,
@@ -52,11 +53,13 @@
     ShapeOp,
     Splat,
     StringLiteral,
+    UnaryOp,
     UpdateStmt,
     Variable,
     construct_infix_op_chain,
     empty_set,
     empty_set_if_none,
+    expr_uses_auto_splat,
     get_object_type_splat,
     toplevel_edgeql,
 )
@@ -95,6 +98,7 @@
     GelSchemaMetadata,
     GelSourceMetadata,
     GelTypeMetadata,
+    GelObjectTypeExprMetadata,
     GelObjectTypeMetadata,
 )
 
@@ -128,6 +132,7 @@
     "ForStmt",
     "FuncCall",
     "GelLinkMetadata",
+    "GelObjectTypeExprMetadata",
     "GelObjectTypeMetadata",
     "GelPointerReflection",
     "GelReflectionProto",
@@ -141,6 +146,7 @@
     "IntLiteral",
     "Limit",
     "Literal",
+    "ObjectWhenType",
     "Offset",
     "OrderBy",
     "OrderByElem",
@@ -150,7 +156,7 @@
     "Path",
     "PathAlias",
     "PathPrefix",
-    "PrefixOp",
+    "PathTypeIntersectionPrefix",
     "SchemaSet",
     "Scope",
     "ScopeContext",
@@ -163,6 +169,7 @@
     "Splat",
     "Stmt",
     "StringLiteral",
+    "UnaryOp",
     "UpdateStmt",
     "VarAlias",
     "Variable",
@@ -171,6 +178,7 @@
     "edgeql_qb_expr",
     "empty_set",
     "empty_set_if_none",
+    "expr_uses_auto_splat",
     "exprmethod",
     "get_object_type_splat",
     "get_origin",

gel/_internal/_qb/_abstract.py

@@ -19,7 +19,7 @@
 
 if TYPE_CHECKING:
     from collections.abc import Iterable, Iterator, Mapping
-    from gel._internal._schemapath import TypeName
+    from gel._internal._schemapath import TypeNameExpr
 
 
 @dataclass(kw_only=True, frozen=True)
@@ -89,7 +89,7 @@ class Expr(Node):
     def precedence(self) -> _edgeql.Precedence: ...
 
     @abc.abstractproperty
-    def type(self) -> TypeName: ...
+    def type(self) -> TypeNameExpr: ...
 
     @abc.abstractmethod
     def __edgeql_expr__(self, *, ctx: ScopeContext) -> str: ...
@@ -100,10 +100,10 @@ def __edgeql_qb_expr__(self) -> Self:
 
 @dataclass(kw_only=True, frozen=True)
 class TypedExpr(Expr):
-    type_: TypeName
+    type_: TypeNameExpr
 
     @property
-    def type(self) -> TypeName:
+    def type(self) -> TypeNameExpr:
         return self.type_
 
 
@@ -494,12 +494,20 @@ def compute_must_bind_refs(
         return (self,)
 
 
+@dataclass(frozen=True, kw_only=True)
+class PathTypeIntersectionPrefix(IdentLikeExpr):
+    type_filter: TypeNameExpr
+
+    def __edgeql_expr__(self, *, ctx: ScopeContext) -> str:
+        return f"[is {self.type_filter.as_quoted_schema_name()}]"
+
+
 @dataclass(kw_only=True, frozen=True)
 class ImplicitIteratorStmt(IteratorExpr, Stmt):
     """Base class for statements that are implicit iterators"""
 
     @property
-    def type(self) -> TypeName:
+    def type(self) -> TypeNameExpr:
         return self.iter_expr.type
 
     @property

gel/_internal/_qb/_expressions.py

@@ -20,7 +20,7 @@
 
 from gel._internal import _edgeql
 from gel._internal._polyfills import _strenum
-from gel._internal._schemapath import SchemaPath, TypeName
+from gel._internal._schemapath import SchemaPath, TypeName, TypeNameExpr
 
 from ._abstract import (
     AtomicExpr,
@@ -239,7 +239,7 @@ def __init__(
         /,
         *,
         op: _edgeql.Token | str,
-        type_: TypeName,
+        type_: TypeNameExpr,
     ) -> None:
         super().__init__(type_=type_)
         if not isinstance(op, _edgeql.Token):
@@ -252,15 +252,15 @@ def precedence(self) -> _edgeql.Precedence:
 
 
 @dataclass(kw_only=True, frozen=True)
-class PrefixOp(Op):
+class UnaryOp(Op):
     expr: Expr
 
     def __init__(
         self,
         *,
         expr: ExprCompatible,
         op: _edgeql.Token | str,
-        type_: TypeName,
+        type_: TypeNameExpr,
     ) -> None:
         object.__setattr__(self, "expr", edgeql_qb_expr(expr))
         super().__init__(op=op, type_=type_)
@@ -276,7 +276,7 @@ def __edgeql_expr__(self, *, ctx: ScopeContext) -> str:
 
 
 @dataclass(kw_only=True, frozen=True)
-class CastOp(PrefixOp):
+class CastOp(UnaryOp):
     def __init__(
         self,
         *,
@@ -300,6 +300,35 @@ def __edgeql_expr__(self, *, ctx: ScopeContext) -> str:
         return f"<{self.type.as_quoted_schema_name()}>{expr}"
 
 
+@dataclass(kw_only=True, frozen=True)
+class ObjectWhenType(UnaryOp):
+    type_filter: TypeNameExpr
+
+    def __init__(
+        self,
+        *,
+        expr: ExprCompatible,
+        type_filter: TypeNameExpr,
+        type_: TypeNameExpr,
+    ) -> None:
+        op = _edgeql.Token.RANGBRACKET
+        object.__setattr__(self, "type_filter", type_filter)
+        super().__init__(expr=expr, op=op, type_=type_)
+
+    @property
+    def precedence(self) -> _edgeql.Precedence:
+        return _edgeql.PRECEDENCE[_edgeql.Token.LBRACKET]
+
+    def subnodes(self) -> Iterable[Node]:
+        return (self.expr,)
+
+    def __edgeql_expr__(self, *, ctx: ScopeContext) -> str:
+        expr = edgeql(self.expr, ctx=ctx)
+        if _need_left_parens(self.precedence, self.expr):
+            expr = f"({expr})"
+        return f"{expr} [is {self.type_filter.as_quoted_schema_name()}]"
+
+
 def empty_set(type_: TypeName) -> CastOp:
     return CastOp(expr=SetLiteral(items=(), type_=type_), type_=type_)
 
@@ -319,7 +348,7 @@ def __init__(
         lexpr: ExprCompatible,
         rexpr: ExprCompatible,
         op: _edgeql.Token | str,
-        type_: TypeName,
+        type_: TypeNameExpr,
     ) -> None:
         object.__setattr__(self, "lexpr", edgeql_qb_expr(lexpr))
         object.__setattr__(self, "rexpr", edgeql_qb_expr(rexpr))
@@ -337,7 +366,7 @@ def __init__(
         lexpr: ExprCompatible,
         rexpr: ExprCompatible,
         op: _edgeql.Token | str,
-        type_: TypeName,
+        type_: TypeNameExpr,
     ) -> None:
         super().__init__(lexpr=lexpr, rexpr=rexpr, op=op, type_=type_)
 
@@ -406,7 +435,7 @@ def __init__(
         fname: str,
         args: list[ExprCompatible] | None = None,
         kwargs: dict[str, ExprCompatible] | None = None,
-        type_: TypeName,
+        type_: TypeNameExpr,
     ) -> None:
         object.__setattr__(self, "fname", fname)
         if args is not None:
@@ -508,7 +537,7 @@ def subnodes(self) -> Iterable[Node]:
         return (self.expr,)
 
     @property
-    def type(self) -> TypeName:
+    def type(self) -> TypeNameExpr:
         return self.expr.type
 
     @property
@@ -588,9 +617,15 @@ def __edgeql_expr__(self, *, ctx: ScopeContext) -> str:
 
 @dataclass(kw_only=True, frozen=True)
 class InsertStmt(Stmt, TypedExpr):
+    type_: TypeName  # insert can only deal with simple type names
+
     stmt: _edgeql.Token = _edgeql.Token.INSERT
     shape: Shape | None = None
 
+    @property
+    def type(self) -> TypeName:
+        return self.type_
+
     def subnodes(self) -> Iterable[Node | None]:
         return (self.shape,)
 
@@ -661,7 +696,7 @@ def wrap(
             kwargs = {}
             if isinstance(expr, ShapeOp):
                 kwargs["body_scope"] = expr.scope
-            elif isinstance(expr, (SchemaSet, Path)):
+            elif expr_uses_auto_splat(expr):
                 if splat_cb is not None:
                     shape = splat_cb()
                 else:
@@ -757,7 +792,7 @@ def __post_init__(self) -> None:
         object.__setattr__(self, "var", var)
 
     @property
-    def type(self) -> TypeName:
+    def type(self) -> TypeNameExpr:
         return self.body.type
 
     def subnodes(self) -> Iterable[Node]:
@@ -786,7 +821,7 @@ class Splat(_strenum.StrEnum):
 @dataclass(kw_only=True, frozen=True)
 class ShapeElement(Node):
     name: str | Splat
-    origin: TypeName
+    origin: TypeNameExpr
     expr: Expr | None = None
 
     def subnodes(self) -> Iterable[Node]:
@@ -798,7 +833,7 @@ def subnodes(self) -> Iterable[Node]:
     @classmethod
     def splat(
         cls,
-        source: TypeName,
+        source: TypeNameExpr,
         *,
         kind: Splat = Splat.STAR,
     ) -> Self:
@@ -815,14 +850,23 @@ def subnodes(self) -> Iterable[Node]:
     @classmethod
     def splat(
         cls,
-        source: TypeName,
+        source: TypeNameExpr,
         *,
         kind: Splat = Splat.STAR,
     ) -> Self:
         elements = [ShapeElement.splat(source=source, kind=kind)]
         return cls(elements=elements)
 
 
+def expr_uses_auto_splat(expr: Expr) -> bool:
+    if isinstance(expr, (SchemaSet, Path)):
+        return True
+    elif isinstance(expr, ObjectWhenType):
+        return expr_uses_auto_splat(expr.expr)
+    else:
+        return False
+
+
 def _render_shape(
     shape: Shape,
     source: Expr,
@@ -873,7 +917,7 @@ def subnodes(self) -> Iterable[Node]:
         return (self.iter_expr, self.shape)
 
     @property
-    def type(self) -> TypeName:
+    def type(self) -> TypeNameExpr:
         return self.iter_expr.type
 
     @property