Files
midas/midas/checker/frames/frame_methods.py

744 lines
23 KiB
Python

from __future__ import annotations
import ast
from dataclasses import dataclass
from typing import TYPE_CHECKING, Optional
import midas.ast.python as p
from midas.ast.location import Location
from midas.checker.dispatcher import CallResult
from midas.checker.frames.utils import MethodRegistry, method
from midas.checker.types import (
ColumnType,
DataFrameType,
FrameGroupBy,
Function,
OverloadedFunction,
ParamSpec,
TopType,
Type,
UnitType,
UnknownType,
unfold_type,
)
if TYPE_CHECKING:
from midas.checker.python import TypedExpr
@dataclass(frozen=True, kw_only=True)
class Call:
"""A frame method call, implements :class:`utils.MethodCall`"""
location: Location
call_expr: p.Expr
frame: DataFrameType
frame_expr: p.Expr
positional: list[TypedExpr]
keywords: dict[str, TypedExpr]
@property
def subject(self) -> TypedExpr:
return (self.frame_expr, self.frame)
class FrameMethodRegistry(MethodRegistry[Call]):
"""The method registry for frame types"""
def _simple_call(self, call: Call, function: Type) -> Type:
"""Get the result of calling a simple method
This function is a simple wrapper around :func:`dispatcher.CallDispatcher.get_result`
Args:
call (Call): the call that triggered this resolution
function (Type): the function type
Returns:
Type: the return type
"""
result: CallResult = self.dispatcher.get_result(
location=call.location,
callee=function,
positional=call.positional,
keywords=call.keywords,
)
return result.result
def _get_method_result(
self,
call: Call,
column1: ColumnType,
column2: ColumnType,
method: str,
) -> ColumnType:
"""Get the result of calling a method on a column, passing a second
This function delegates to the main typer the resolution of the method
member, as well as computing the result type. Because we don't have any
AST expression for the individual columns, the frame expressions are
used instead.
Args:
call (Call): the call that triggered this resolution
column1 (ColumnType): the first column, i.e. left operand
column2 (ColumnType): the second column, i.e. right operand
method (str): the method name
Returns:
ColumnType: the resulting column.
If the operation is invalid / doesn't exist,
`ColumnType(type=UnknownType())` is returned
"""
result: Type = self.typer.result_of_binary_op(
location=call.location,
expr=call.call_expr,
left=(call.frame_expr, column1),
right=(call.positional[0][0], column2),
method=method,
)
if not isinstance(result, ColumnType):
return ColumnType(type=UnknownType())
return result
def _element_binary_op(self, call: Call, method: str) -> tuple[Type, bool]:
"""Compute the result of an element-wise binary operation
This function delegates to the matching columns for computing resulting
types. Any column only present in one of the frames is forwarded as a
generic `ColumnType(type=UnknownType())`. Columns only in the second
frame are append at the end of the schema.
Args:
call (Call): the call that triggered this resolution
method (str): the method name
Returns:
tuple[Type, bool]: the resulting type and a boolean indicating
whether the operand is a frame
"""
if len(call.positional) == 0:
return UnknownType(), False
operand: TypedExpr = call.positional[0]
new_columns: list[DataFrameType.Column] = []
by_name: dict[str, DataFrameType.Column] = {}
frame2: Optional[DataFrameType] = None
# Get map of operand's columns by name, if the operand is a dataframe
unfolded_other: Type = unfold_type(operand[1])
frame_operand: bool = isinstance(unfolded_other, DataFrameType)
if frame_operand:
frame2 = unfolded_other
by_name = {col.name: col for col in frame2.columns if col.name is not None}
# Compute new schema:
# Step 1: for all columns in frame1:
# - if present in frame2 -> delegate operation to columns
# - if not -> add to schema as unknown
in_frame1: set[str] = set()
for column in call.frame.columns:
if column.name is not None:
in_frame1.add(column.name)
col_type1: ColumnType = column.type
col_type: ColumnType = ColumnType(type=UnknownType())
col_type2: Optional[ColumnType] = None
# Operand is a frame -> lookup column with the same name
if frame2 is not None:
if column.name in by_name:
column2 = by_name[column.name]
col_type2 = column2.type
# Operand is not a frame -> scalar operation -> ad-hoc column
else:
col_type2 = ColumnType(type=operand[1])
if col_type2 is not None:
with self.reporter.with_context(f"in column '{column.name}'"):
col_type = self._get_method_result(
call, col_type1, col_type2, method
)
new_column = DataFrameType.Column(
index=column.index,
name=column.name,
type=col_type,
)
new_columns.append(new_column)
# Step 2: for all columns in frame2
# - if not in frame1 -> add to schema as unknown
if frame2 is not None:
for column in frame2.columns:
if column.name in in_frame1:
continue
new_columns.append(
DataFrameType.Column(
index=len(new_columns),
name=column.name,
type=ColumnType(type=UnknownType()),
)
)
return DataFrameType(columns=new_columns), frame_operand
def _element_wise(self, call: Call, method: str) -> Type:
"""Compute the result of an element-wise method call
If the call is valid, this method also generates an assertion to check
that both operands have the same length at runtime
Args:
call (Call): the call object
method (str): the method's name
Returns:
Type: the result type
"""
# TODO: support sequence, Series, dict operand
returns, frame_operand = self._element_binary_op(call, method)
# Build signature with new schema and generic operand
signature = Function(
params=ParamSpec(
mixed=[
Function.Parameter(
pos=0,
name="other",
type=TopType(),
required=True,
),
],
),
returns=returns,
)
# Map arguments and compute result type
result: CallResult = self.dispatcher.get_result(
location=call.location,
callee=signature,
positional=call.positional,
keywords=call.keywords,
)
if result.is_valid and frame_operand:
self._assert_same_length(
call.call_expr, call.frame_expr, call.positional[0][0]
)
return result.result
@method()
def copy(self, call: Call) -> Type:
return self._simple_call(
call,
Function(
params=ParamSpec(
mixed=[
Function.Parameter(
pos=0,
name="deep",
type=self.types.get_type("bool"),
required=False,
)
]
),
returns=call.frame,
),
)
@method()
def info(self, call: Call) -> Type:
def make_overload(memory_usage: Type, required: bool = False) -> Type:
return Function(
params=ParamSpec(
mixed=[
Function.Parameter(
pos=0,
name="verbose",
type=self.types.get_type("bool"),
required=False,
),
Function.Parameter(
pos=1,
name="buf",
type=TopType(),
required=False,
),
Function.Parameter(
pos=2,
name="max_cols",
type=self.types.get_type("int"),
required=False,
),
Function.Parameter(
pos=3,
name="memory_usage",
type=memory_usage,
required=required,
),
Function.Parameter(
pos=4,
name="show_counts",
type=self.types.get_type("bool"),
required=False,
),
]
),
returns=UnitType(),
)
return self._simple_call(
call,
OverloadedFunction(
overloads=[
make_overload(self.types.get_type("bool"), False),
make_overload(self.types.get_type("str"), True),
],
),
)
@method("add", "__add__")
def add(self, call: Call) -> Type:
return self._element_wise(call, "__add__")
@method("sub", "__sub__")
def sub(self, call: Call) -> Type:
return self._element_wise(call, "__sub__")
@method("mul", "__mul__")
def mul(self, call: Call) -> Type:
return self._element_wise(call, "__mul__")
@method("div", "truediv", "__truediv__")
def truediv(self, call: Call) -> Type:
return self._element_wise(call, "__truediv__")
@method("floordiv", "__floordiv__")
def floordiv(self, call: Call) -> Type:
return self._element_wise(call, "__floordiv__")
@method("mod", "__mod__")
def mod(self, call: Call) -> Type:
return self._element_wise(call, "__mod__")
@method("pow", "__pow__")
def pow(self, call: Call) -> Type:
return self._element_wise(call, "__pow__")
@method("lt", "__lt__")
def lt(self, call: Call) -> Type:
return self._element_wise(call, "__lt__")
@method("gt", "__gt__")
def gt(self, call: Call) -> Type:
return self._element_wise(call, "__gt__")
@method("le", "__le__")
def le(self, call: Call) -> Type:
return self._element_wise(call, "__le__")
@method("ge", "__ge__")
def ge(self, call: Call) -> Type:
return self._element_wise(call, "__ge__")
@method("ne", "__ne__")
def ne(self, call: Call) -> Type:
return self._element_wise(call, "__ne__")
@method("eq", "__eq__")
def eq(self, call: Call) -> Type:
return self._element_wise(call, "__eq__")
def _aggregate(self, call: Call, kwargs: list[Function.Parameter] = []) -> Type:
"""Compute the result type of an aggregate method call
Args:
call (Call): the call object
kwargs (list[Function.Parameter], optional): a list of extra
keyword-only parameters. Defaults to [].
Returns:
Type: the result type
"""
with_axis = Function(
params=ParamSpec(
kw=[
Function.Parameter(
pos=0,
name="axis",
type=self.types.get_type("int"),
required=False,
),
*kwargs,
],
),
returns=ColumnType(type=TopType()),
)
without_axis = Function(
params=ParamSpec(
kw=[
Function.Parameter(
pos=0,
name="axis",
type=self.types.get_type("None"),
required=True,
),
*kwargs,
],
),
returns=TopType(),
)
overload = OverloadedFunction(
overloads=[
with_axis,
without_axis,
]
)
result: CallResult = self.dispatcher.get_result(
location=call.location,
callee=overload,
positional=call.positional,
keywords=call.keywords,
)
return result.result
@method("kurtosis", "kurt")
def kurtosis(self, call: Call) -> Type:
return self._aggregate(call)
@method()
def max(self, call: Call) -> Type:
return self._aggregate(call)
@method()
def mean(self, call: Call) -> Type:
return self._aggregate(call)
@method()
def median(self, call: Call) -> Type:
return self._aggregate(call)
@method()
def min(self, call: Call) -> Type:
return self._aggregate(call)
@method()
def mode(self, call: Call) -> Type:
return self._aggregate(call)
@method("product", "prod")
def product(self, call: Call) -> Type:
return self._aggregate(call)
@method()
def std(self, call: Call) -> Type:
return self._aggregate(
call,
[
Function.Parameter(
pos=1,
name="ddof",
type=self.types.get_type("int"),
required=False,
)
],
)
@method()
def sum(self, call: Call) -> Type:
return self._aggregate(call)
@method()
def var(self, call: Call) -> Type:
return self._aggregate(
call,
[
Function.Parameter(
pos=1,
name="var",
type=self.types.get_type("int"),
required=False,
)
],
)
@method()
def head(self, call: Call) -> Type:
signature = Function(
params=ParamSpec(
mixed=[
Function.Parameter(
pos=0,
name="n",
type=self.types.get_type("int"),
required=False,
),
],
),
returns=call.frame,
)
result: CallResult = self.dispatcher.get_result(
location=call.location,
callee=signature,
positional=call.positional,
keywords=call.keywords,
)
return result.result
@method()
def tail(self, call: Call) -> Type:
signature = Function(
params=ParamSpec(
mixed=[
Function.Parameter(
pos=0,
name="n",
type=self.types.get_type("int"),
required=False,
),
],
),
returns=call.frame,
)
result: CallResult = self.dispatcher.get_result(
location=call.location,
callee=signature,
positional=call.positional,
keywords=call.keywords,
)
return result.result
@method()
def sort_values(self, call: Call) -> Type:
str_ = self.types.get_type("str")
bool_ = self.types.get_type("bool")
def make_overload(by: Type, ascending: Type) -> Function:
return Function(
params=ParamSpec(
mixed=[
Function.Parameter(
pos=0,
name="by",
type=by,
required=True,
),
],
kw=[
Function.Parameter(
pos=1,
name="axis",
type=TopType(),
required=False,
),
Function.Parameter(
pos=2,
name="ascending",
type=ascending,
required=False,
),
Function.Parameter(
pos=3,
name="inplace",
type=bool_,
required=False,
unsupported=True,
),
Function.Parameter(
pos=4,
name="kind",
type=str_,
required=False,
),
Function.Parameter(
pos=5,
name="na_position",
type=str_,
required=False,
),
Function.Parameter(
pos=6,
name="ignore_index",
type=bool_,
required=False,
),
Function.Parameter(
pos=7,
name="key",
type=TopType(),
required=False,
),
],
),
returns=call.frame,
)
list_of = self.types.list_of
overloads: list[Type] = [
make_overload(by=str_, ascending=bool_),
make_overload(by=list_of(str_), ascending=bool_),
make_overload(by=str_, ascending=list_of(bool_)),
make_overload(by=list_of(str_), ascending=list_of(bool_)),
]
# TODO: check that literal strings in `by` are valid columns
result: CallResult = self.dispatcher.get_result(
location=call.location,
callee=OverloadedFunction(overloads=overloads),
positional=call.positional,
keywords=call.keywords,
)
return result.result
def _filter_groupby_columns(
self, frame: DataFrameType, by: TypedExpr
) -> DataFrameType:
by_columns: list[str] = []
by_expr, _ = by
if not isinstance(by_expr, p.ListExpr):
return frame
for item in by_expr.items:
match item:
case p.LiteralExpr(value=str() as name):
by_columns.append(name)
new_columns: list[DataFrameType.Column] = []
for column in frame.columns:
if column.name in by_columns:
continue
new_columns.append(
DataFrameType.Column(
index=len(new_columns),
name=column.name,
type=column.type,
)
)
return DataFrameType(columns=new_columns)
@method()
def groupby(self, call: Call) -> Type:
new_frame: DataFrameType = call.frame
by: Optional[TypedExpr] = None
if len(call.positional) != 0:
by = call.positional[0]
elif "by" in call.keywords:
by = call.keywords["by"]
if by is not None:
new_frame = self._filter_groupby_columns(call.frame, by)
bool_: Type = self.types.get_type("bool")
function: Function = Function(
params=ParamSpec(
mixed=[
Function.Parameter(
pos=0,
name="by",
type=TopType(),
required=False,
),
Function.Parameter(
pos=1,
name="level",
type=TopType(),
required=False,
),
],
kw=[
Function.Parameter(
pos=i + 2,
name=name,
type=bool_,
required=False,
)
for i, name in enumerate(
["as_index", "sort", "group_keys", "observed", "dropna"]
)
],
),
returns=FrameGroupBy(frame=new_frame),
)
result: CallResult = self.dispatcher.get_result(
location=call.location,
callee=function,
positional=call.positional,
keywords=call.keywords,
)
return result.result
def _assert_same_length(self, call_expr: p.Expr, frame1: p.Expr, frame2: p.Expr):
"""Generate an assertion to check that two frames have the same length
Args:
call_expr (p.Expr): the call expression, to insert the assertion
at the right place
frame1 (p.Expr): the first frame expression
frame2 (p.Expr): the second frame expression
"""
func_name: str = "__midas_frame_same_length__"
# Efficiently compute length
# https://stackoverflow.com/a/15943975/11109181
def len_of_df(df: ast.expr) -> ast.expr:
return ast.Call(
func=ast.Name(id="len"),
args=[
ast.Attribute(
value=df,
attr="index",
)
],
keywords=[],
)
self.assertions.define(
func_name,
ast.FunctionDef(
name=func_name,
args=ast.arguments(
posonlyargs=[],
args=[
ast.arg(arg="frame1"),
ast.arg(arg="frame2"),
],
kwonlyargs=[],
defaults=[],
kw_defaults=[],
),
body=[
ast.Return(
value=ast.Compare(
left=len_of_df(ast.Name(id="frame1")),
ops=[ast.Eq()],
comparators=[len_of_df(ast.Name(id="frame2"))],
)
)
],
decorator_list=[],
),
)
self.assertions.add(
bound_expr=call_expr,
inputs=[frame1, frame2],
builder=lambda f1, f2: ast.Call(
func=ast.Name(id=func_name),
args=[f1, f2],
keywords=[],
),
message="DataFrames must have the same length",
)