feat(gen): add base for stubs generator

This commit is contained in:
2026-06-17 12:19:32 +02:00
parent df8d71c0a9
commit e8f8a5ca2f

337
midas/generator/stubs.py Normal file
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import ast
from typing import Optional
import midas.ast.midas as m
from midas.checker.registry import Member, TypesRegistry
from midas.checker.types import (
AliasType,
AppliedType,
BaseType,
ComplexType,
ExtensionType,
Function,
GenericType,
OverloadedFunction,
TopType,
Type,
TypeVar,
UnitType,
UnknownType,
substitute_typevars,
)
Empty = ast.Constant(value=...)
class StubsGenerator:
def __init__(self, types: TypesRegistry) -> None:
self.types: TypesRegistry = types
self.stubs: list[ast.stmt] = []
self.typing_imports: set[str] = set()
self.protocol_idx: int = 0
self.stub_idx: int = 0
self.type_var_idx: int = 0
self.substitutions: dict[str, dict[str, Type]] = {}
def generate_stubs(self) -> ast.Module:
self.stubs = []
self.typing_imports = set()
for name, type in self.types._types.items():
self.generate_stub(name, type)
imports = [
ast.ImportFrom(
module="__future__",
names=[ast.alias(name="annotations")],
level=0,
)
]
if len(self.typing_imports) != 0:
imports.append(
ast.ImportFrom(
module="typing",
names=[
ast.alias(name=name) for name in sorted(self.typing_imports)
],
level=0,
)
)
return ast.Module(body=imports + self.stubs, type_ignores=[])
def generate_stub(self, name: str, type: Type):
base_type: Type = type
members: dict[str, Member] = self.types._members.get(name, {})
if isinstance(base_type, (BaseType, TopType, UnitType)) and len(members) == 0:
return
bases: list[ast.expr] = []
substitutions: dict[str, Type] = {}
bases, substitutions = self.get_bases(type)
self.substitutions[name] = substitutions
body = self.generate_body(members, substitutions)
stub = ast.ClassDef(
name=name,
bases=bases,
body=body,
keywords=[],
decorator_list=[],
)
self.add_stub(stub)
def get_bases(self, type: Type) -> tuple[list[ast.expr], dict[str, Type]]:
match type:
case AliasType(type=base):
return [self.dump_type(base)], {}
case GenericType(params=params, body=body):
self.add_typing_import("Generic")
type_vars: ast.expr
params2: list[TypeVar] = self.define_type_vars(params)
if len(params) == 1:
type_vars = ast.Name(id=params2[0].name)
else:
type_vars = ast.Tuple(
elts=[ast.Name(id=param.name) for param in params2]
)
substitutions: dict[str, TypeVar] = {
param.name: param2 for param, param2 in zip(params, params2)
}
body_bases, body_subsitutions = self.get_bases(body)
return (
body_bases
+ [
ast.Subscript(
value=ast.Name(id="Generic"),
slice=type_vars,
)
],
body_subsitutions | substitutions,
)
case _:
return [], {}
def generate_body(
self, members: dict[str, Member], substitutions: dict[str, Type]
) -> list[ast.stmt]:
if len(members) == 0:
return [ast.Expr(value=Empty)]
body: list[ast.stmt] = []
for name, member in members.items():
type: Type = member.type
type = substitute_typevars(type, substitutions)
match member.kind:
case m.MemberKind.PROPERTY:
body.append(
ast.AnnAssign(
target=ast.Name(id=name),
annotation=self.dump_type(type),
simple=1,
)
)
case m.MemberKind.METHOD:
body.extend(self.dump_method(name, type))
return body
def dump_type(self, type: Type) -> ast.expr:
match type:
case AliasType(name=name) | GenericType(name=name) if (
name in self.substitutions
):
type = substitute_typevars(type, self.substitutions[name])
match type:
case TopType() | UnknownType():
self.add_typing_import("Any")
return ast.Name(id="Any")
case BaseType(name=name):
return ast.Name(id=name)
case AliasType(name=name):
return ast.Name(id=name)
case UnitType():
return ast.Constant(value=None)
case Function():
name: str = self.define_protocol(type)
return ast.Name(id=name)
case OverloadedFunction(overloads=overloads):
if len(overloads) == 1:
return self.dump_type(overloads[0])
return ast.BinOp(
left=self.dump_type(OverloadedFunction(overloads=overloads[:-1])),
op=ast.BitOr(),
right=self.dump_type(overloads[-1]),
)
case ComplexType():
name: str = self.new_stub_name()
self.generate_stub(name, type)
return ast.Name(id=name)
case ExtensionType():
raise NotImplementedError
case TypeVar():
return ast.Name(id=type.name)
case GenericType(name=name):
params: ast.expr
if len(type.params) == 1:
params = self.dump_type(type.params[0])
else:
params = ast.Tuple(
elts=[self.dump_type(param) for param in type.params]
)
return ast.Subscript(
value=ast.Name(id=type.name),
slice=params,
)
case AppliedType():
args: ast.expr
if len(type.args) == 1:
args = self.dump_type(type.args[0])
else:
args = ast.Tuple(elts=[self.dump_type(arg) for arg in type.args])
return ast.Subscript(
value=ast.Name(id=type.name),
slice=args,
)
def dump_method(
self, name: str, method: Type, overloaded: bool = False
) -> list[ast.stmt]:
match method:
case Function():
if overloaded:
self.add_typing_import("overload")
return [
ast.FunctionDef(
name=name,
args=self.dump_args(method, with_self=True),
returns=self.dump_type(method.returns),
body=[ast.Expr(value=Empty)],
decorator_list=[ast.Name(id="overload")] if overloaded else [],
)
]
case OverloadedFunction(overloads=overloads):
stmts: list[ast.stmt] = []
for overload in overloads:
stmts.extend(self.dump_method(name, overload, True))
return stmts
case _:
return [
ast.AnnAssign(
target=ast.Name(id=name),
annotation=self.dump_type(method),
simple=1,
)
]
def dump_args(self, func: Function, with_self: bool = False) -> ast.arguments:
pos: list[ast.arg] = [
ast.arg(arg=f"_{arg.pos}", annotation=self.dump_type(arg.type))
for arg in func.pos_args
]
mixed: list[ast.arg] = [
ast.arg(arg=arg.name, annotation=self.dump_type(arg.type))
for arg in func.args
]
kw: list[ast.arg] = [
ast.arg(arg=arg.name, annotation=self.dump_type(arg.type))
for arg in func.kw_args
]
defaults: list[ast.expr] = [
Empty for arg in func.pos_args + func.args if not arg.required
]
kw_defaults: list[Optional[ast.expr]] = [
None if arg.required else Empty for arg in func.kw_args
]
if with_self:
arg = ast.arg(arg="self", annotation=None)
if len(pos) != 0:
pos.insert(0, arg)
else:
mixed.insert(0, arg)
return ast.arguments(
posonlyargs=pos,
args=mixed,
kwonlyargs=kw,
defaults=defaults,
kw_defaults=kw_defaults,
)
def define_protocol(self, func: Function) -> str:
self.add_typing_import("Protocol")
name: str = self.new_protocol_name()
protocol = ast.ClassDef(
name=name,
bases=[ast.Name(id="Protocol")],
keywords=[],
body=[
ast.FunctionDef(
name="__call__",
args=self.dump_args(func, with_self=True),
returns=self.dump_type(func.returns),
body=[ast.Expr(value=Empty)],
decorator_list=[],
),
],
decorator_list=[],
)
self.add_stub(protocol)
return name
def new_protocol_name(self) -> str:
name: str = f"_Protocol{self.protocol_idx}"
self.protocol_idx += 1
return name
def new_stub_name(self) -> str:
name: str = f"_Stub_{self.stub_idx}"
self.stub_idx += 1
return name
def new_type_var_name(self) -> str:
name: str = f"_T{self.type_var_idx}"
self.type_var_idx += 1
return name
def add_stub(self, stub: ast.stmt):
self.stubs.append(stub)
def add_typing_import(self, name: str):
self.typing_imports.add(name)
def define_type_vars(self, vars: list[TypeVar]) -> list[TypeVar]:
vars2: list[TypeVar] = []
for var in vars:
vars2.append(self.define_type_var(var))
return vars2
def define_type_var(self, var: TypeVar) -> TypeVar:
name: str = self.new_type_var_name()
self.add_typing_import("TypeVar")
self.add_stub(
ast.Assign(
targets=[ast.Name(id=name)],
value=ast.Call(
func=ast.Name(id="TypeVar"),
args=[
ast.Constant(value=name),
],
keywords=(
[]
if var.bound is None
else [
ast.keyword(
arg="bound",
value=self.dump_type(var.bound),
)
]
),
),
)
)
return TypeVar(name=name, bound=None)