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Dialects for Python Syntax Sugar

This page contains the dialects designed to represent Python syntax sugar. They provide an implementation of lowering transform from the corresponding Python AST to the dialects' statements. All the statements are typed Any thus one can always use a custom rewrite pass after type inference to support the desired syntax sugar.

Reference

Indexing

kirin.dialects.py.indexing

The indexing dialect for Python.

This module contains the dialect for the Python indexing syntax, including:

  • The GetItem statement class.
  • A base class Subscript for indexing statements.
  • A trait GetItemLike for indexing statements.
  • The lowering pass for the indexing statement.
  • The concrete implementation of the indexing statement.
  • The constant propagation implementation (special case) of the indexing statement.
  • The type inference implementation of the indexing statement.
  • A canonical rewrite rule for the rewriting of a given getitem-like statement to another getitem-like statement.

GetItemLikeStmt module-attribute 

GetItemLikeStmt = TypeVar(
    "GetItemLikeStmt", bound=Statement
)

PyGetItemLikeStmt module-attribute 

PyGetItemLikeStmt = TypeVar(
    "PyGetItemLikeStmt", bound="GetItem"
)

dialect module-attribute 

dialect = Dialect('py.indexing')

Concrete dataclass 

Concrete()

Bases: MethodTable

getindex 

getindex(interp, frame: interp.Frame, stmt: GetItem)
Source code in src/kirin/dialects/py/indexing.py 
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@interp.impl(GetItem)
def getindex(self, interp, frame: interp.Frame, stmt: GetItem):
    return (frame.get(stmt.obj)[frame.get(stmt.index)],)

ConstProp dataclass 

ConstProp()

Bases: MethodTable

getitem 

getitem(
    _: const.Propagate, frame: const.Frame, stmt: GetItem
) -> interp.StatementResult[const.Result]
Source code in src/kirin/dialects/py/indexing.py 
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@interp.impl(GetItem)
def getitem(
    self,
    _: const.Propagate,
    frame: const.Frame,
    stmt: GetItem,
) -> interp.StatementResult[const.Result]:
    obj = frame.get(stmt.obj)
    index = frame.get(stmt.index)
    if not isinstance(index, const.Value):
        return (const.Unknown(),)

    if isinstance(obj, const.Value):
        return (const.Value(obj.data[index.data]),)
    elif isinstance(obj, const.PartialTuple):
        obj = obj.data
        if isinstance(index.data, int) and 0 <= index.data < len(obj):
            return (obj[index.data],)
        elif isinstance(index.data, slice):
            start, stop, step = index.data.indices(len(obj))
            return (const.PartialTuple(obj[start:stop:step]),)
    return (const.Unknown(),)

GetItem kirin-statement 

GetItem(obj: ir.SSAValue, index: ir.SSAValue)

Bases: Subscript

index kirin-argument 

index: SSAValue = argument(print=False)

name class-attribute instance-attribute 

name = 'getitem'

obj kirin-argument 

obj: SSAValue = argument(print=False)

result kirin-result 

result: ResultValue = result(Any)

traits class-attribute instance-attribute 

traits = frozenset(
    {Pure(), PyGetItemLike(), FromPythonCall()}
)

GetItemLike dataclass 

GetItemLike()

Bases: StmtTrait, Generic[GetItemLikeStmt]

get_index abstractmethod 

get_index(stmt: GetItemLikeStmt) -> ir.SSAValue
Source code in src/kirin/dialects/py/indexing.py 
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@abstractmethod
def get_index(self, stmt: GetItemLikeStmt) -> ir.SSAValue: ...

get_object abstractmethod 

get_object(stmt: GetItemLikeStmt) -> ir.SSAValue
Source code in src/kirin/dialects/py/indexing.py 
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@abstractmethod
def get_object(self, stmt: GetItemLikeStmt) -> ir.SSAValue: ...

new abstractmethod 

new(
    stmt_type: type[GetItemLikeStmt],
    obj: ir.SSAValue,
    index: ir.SSAValue,
) -> GetItemLikeStmt
Source code in src/kirin/dialects/py/indexing.py 
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@abstractmethod
def new(
    self, stmt_type: type[GetItemLikeStmt], obj: ir.SSAValue, index: ir.SSAValue
) -> GetItemLikeStmt: ...

Lowering

Bases: FromPythonAST

lower_Subscript 

lower_Subscript(
    state: lowering.LoweringState, node: ast.Subscript
) -> lowering.Result
Source code in src/kirin/dialects/py/indexing.py 
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def lower_Subscript(
    self, state: lowering.LoweringState, node: ast.Subscript
) -> lowering.Result:
    value = state.visit(node.value).expect_one()
    slice = state.visit(node.slice).expect_one()
    if isinstance(node.ctx, ast.Load):
        stmt = GetItem(obj=value, index=slice)
    else:
        raise exceptions.DialectLoweringError(
            f"unsupported subscript context {node.ctx}"
        )
    state.append_stmt(stmt)
    return lowering.Result(stmt)

PyGetItemLike dataclass 

PyGetItemLike()

Bases: GetItemLike[PyGetItemLikeStmt]

get_index 

get_index(stmt: PyGetItemLikeStmt) -> ir.SSAValue
Source code in src/kirin/dialects/py/indexing.py 
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def get_index(self, stmt: PyGetItemLikeStmt) -> ir.SSAValue:
    return stmt.index

get_object 

get_object(stmt: PyGetItemLikeStmt) -> ir.SSAValue
Source code in src/kirin/dialects/py/indexing.py 
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def get_object(self, stmt: PyGetItemLikeStmt) -> ir.SSAValue:
    return stmt.obj

new 

new(
    stmt_type: type[PyGetItemLikeStmt],
    obj: ir.SSAValue,
    index: ir.SSAValue,
) -> PyGetItemLikeStmt
Source code in src/kirin/dialects/py/indexing.py 
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def new(
    self, stmt_type: type[PyGetItemLikeStmt], obj: ir.SSAValue, index: ir.SSAValue
) -> PyGetItemLikeStmt:
    return stmt_type(obj=obj, index=index)

RewriteGetItem dataclass 

RewriteGetItem(
    stmt_type: type[GetItemLikeStmt],
    obj_type: types.TypeAttribute,
)

Bases: RewriteRule, Generic[GetItemLikeStmt]

Source code in src/kirin/dialects/py/indexing.py 
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def __init__(self, stmt_type: type[GetItemLikeStmt], obj_type: types.TypeAttribute):
    trait = stmt_type.get_trait(GetItemLike)
    if trait is None:
        raise ValueError(f"{stmt_type} does not have GetItemLike trait")

    self.obj_type = obj_type
    self.target_stmt_type = stmt_type
    self.getitem_like = trait

getitem_like instance-attribute 

getitem_like: GetItemLike[GetItemLikeStmt] = trait

obj_type instance-attribute 

obj_type: TypeAttribute = obj_type

target_stmt_type instance-attribute 

target_stmt_type: type[GetItemLikeStmt] = stmt_type

rewrite_Statement 

rewrite_Statement(node: ir.Statement) -> RewriteResult
Source code in src/kirin/dialects/py/indexing.py 
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def rewrite_Statement(self, node: ir.Statement) -> RewriteResult:
    if not isinstance(node, GetItem):
        return RewriteResult()

    if not node.obj.type.is_subseteq(self.obj_type):
        return RewriteResult()

    node.replace_by(
        self.getitem_like.new(self.target_stmt_type, node.obj, node.index)
    )
    return RewriteResult(has_done_something=True)

Subscript kirin-statement 

Subscript()

Bases: Statement

TypeInfer dataclass 

TypeInfer()

Bases: MethodTable

getitem 

getitem(
    interp: TypeInference,
    frame: interp.Frame[types.TypeAttribute],
    stmt: GetItem,
)
Source code in src/kirin/dialects/py/indexing.py 
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@interp.impl(GetItem)
def getitem(
    self,
    interp: TypeInference,
    frame: interp.Frame[types.TypeAttribute],
    stmt: GetItem,
):
    obj = frame.get(stmt.obj)
    index: types.TypeAttribute = frame.get(stmt.index)
    # TODO: replace this when we can multiple dispatch
    if obj.is_subseteq(types.Tuple):
        return self.getitem_tuple(interp, stmt, obj, index)
    elif obj.is_subseteq(types.String):
        return (types.String,)
    else:
        return (types.Any,)

getitem_tuple 

getitem_tuple(
    interp,
    stmt: GetItem,
    obj: types.TypeAttribute,
    index: types.TypeAttribute,
)
Source code in src/kirin/dialects/py/indexing.py 
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def getitem_tuple(
    self,
    interp,
    stmt: GetItem,
    obj: types.TypeAttribute,
    index: types.TypeAttribute,
):
    if isinstance(obj, types.Generic):
        if index.is_subseteq(types.Int):
            return self.getitem_tuple_index(interp, stmt, obj, index)
        elif index.is_subseteq(types.Slice):
            return self.getitem_tuple_slice(interp, stmt, obj, index)
        else:
            return (types.Bottom,)
    elif isinstance(obj, types.PyClass):
        return (types.Any,)
    else:
        return (types.Bottom,)

getitem_tuple_index 

getitem_tuple_index(
    interp: TypeInference,
    stmt: GetItem,
    obj: types.Generic,
    index: types.TypeAttribute,
)
Source code in src/kirin/dialects/py/indexing.py 
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def getitem_tuple_index(
    self,
    interp: TypeInference,
    stmt: GetItem,
    obj: types.Generic,
    index: types.TypeAttribute,
):
    if index_ := interp.maybe_const(stmt.index, int):
        if obj.vararg and (index_ >= len(obj.vars) or -len(obj.vars) <= index_ < 0):
            return (obj.vararg.typ,)
        elif obj.vars and (
            0 <= index_ < len(obj.vars) or -len(obj.vars) <= index_ < 0
        ):
            return (obj.vars[index_],)
        else:
            return (types.Bottom,)
    else:
        return (self.getitem_tuple_union(obj),)

getitem_tuple_slice 

getitem_tuple_slice(
    interp: TypeInference,
    stmt: GetItem,
    obj: types.Generic,
    index: types.TypeAttribute,
)
Source code in src/kirin/dialects/py/indexing.py 
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def getitem_tuple_slice(
    self,
    interp: TypeInference,
    stmt: GetItem,
    obj: types.Generic,
    index: types.TypeAttribute,
):
    if index_ := interp.maybe_const(stmt.index, slice):
        if obj.vararg and index_.stop >= len(obj.vars):
            return (
                types.Union(
                    *obj.vars[slice(index_.start, len(obj.vars), index_.step)],
                    obj.vararg.typ,
                ),
            )
        elif index_.stop is None or index_.stop < len(obj.vars):
            return (
                types.Tuple.where(
                    obj.vars[slice(index_.start, index_.stop, index_.step)]
                ),
            )
        else:  # out of bounds
            return (types.Bottom,)
    else:
        return (types.Tuple[types.Vararg(self.getitem_tuple_union(obj))],)

getitem_tuple_union 

getitem_tuple_union(obj: types.Generic)
Source code in src/kirin/dialects/py/indexing.py 
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def getitem_tuple_union(self, obj: types.Generic):
    if obj.vararg:
        return types.Union(*obj.vars, obj.vararg.typ)
    else:
        return types.Union(*obj.vars)

Attribute

kirin.dialects.py.attr

Attribute access dialect for Python.

This module contains the dialect for the Python attribute access statement, including:

  • The GetAttr statement class.
  • The lowering pass for the attribute access statement.
  • The concrete implementation of the attribute access statement.

This dialect maps ast.Attribute nodes to the GetAttr statement.

dialect module-attribute 

dialect = Dialect('py.attr')

Concrete dataclass 

Concrete()

Bases: MethodTable

getattr 

getattr(
    interp: interp.Interpreter,
    frame: interp.Frame,
    stmt: GetAttr,
)
Source code in src/kirin/dialects/py/attr.py 
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@interp.impl(GetAttr)
def getattr(self, interp: interp.Interpreter, frame: interp.Frame, stmt: GetAttr):
    return (getattr(frame.get(stmt.obj), stmt.attrname),)

GetAttr kirin-statement 

GetAttr(obj: ir.SSAValue, *, attrname: str)

Bases: Statement

attrname kirin-attribute kw-only 

attrname: str = attribute()

name class-attribute instance-attribute 

name = 'getattr'

obj kirin-argument 

obj: SSAValue = argument(print=False)

result kirin-result 

result: ResultValue = result()

traits class-attribute instance-attribute 

traits = frozenset({FromPythonCall()})

Lowering

Bases: FromPythonAST

lower_Attribute 

lower_Attribute(
    state: lowering.LoweringState, node: ast.Attribute
) -> lowering.Result
Source code in src/kirin/dialects/py/attr.py 
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def lower_Attribute(
    self, state: lowering.LoweringState, node: ast.Attribute
) -> lowering.Result:
    from kirin.dialects.py import Constant

    if not isinstance(node.ctx, ast.Load):
        raise exceptions.DialectLoweringError(
            f"unsupported attribute context {node.ctx}"
        )

    # NOTE: eagerly load global variables
    value = state.get_global_nothrow(node)
    if value is not None:
        stmt = state.append_stmt(Constant(value.unwrap()))
        return lowering.Result(stmt)

    value = state.visit(node.value).expect_one()
    stmt = GetAttr(obj=value, attrname=node.attr)
    state.append_stmt(stmt)
    return lowering.Result(stmt)