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implementing function call check

This commit is contained in:
pca006132 2020-12-18 13:03:36 +08:00 committed by pca006132
parent fe6d9cc446
commit ce031999e9
7 changed files with 233 additions and 31 deletions
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9
toy-impl/helper.py Normal file
View File

@ -0,0 +1,9 @@
class CustomError(Exception):
def __init__(self, msg):
self.msg = msg
def stringify_subst(subst):
if isinstance(subst, str):
return subst
elements = [f"{key}: {str(value)}" for key, value in subst.items()]
return "{" + ', '.join(elements) + "}"

101
toy-impl/inference.py
View File

@ -1,12 +1,15 @@
from type_def import *
from helper import *
def find_subst(ctx: dict[str, Type],
sub: dict[str, Type],
a: Type,
b: Type):
"""
Find substitution s such that ctx(a) = s(sub(ctx(b)))
return error message if type mismatch
Find substitution s such that ctx(a) = s(sub(b)).
Note that variables in a and b are considered independent.
return s.sub if such s exists (. means function composition).
return error message if type mismatch.
"""
# is error
if isinstance(sub, str):
@ -16,9 +19,7 @@ def find_subst(ctx: dict[str, Type],
a = ctx[a.name]
if isinstance(b, TypeVariable):
if b.name in ctx:
b = ctx[b.name]
elif b.name in sub:
if b.name in sub:
b = sub[b.name]
else:
if len(b.constraints) > 0:
@ -32,10 +33,6 @@ def find_subst(ctx: dict[str, Type],
else:
if a not in b.constraints:
return f"{b} cannot take value of {a}"
if a == b:
return sub
if b in a.get_vars():
return "Recursive type is not supported"
sub[b.name] = a
return sub
@ -47,8 +44,12 @@ def find_subst(ctx: dict[str, Type],
if isinstance(a, BotType):
return sub
# TODO: virtual type is not handled currently
# we need to access the class dictionary to handle this
if type(a) == type(b):
if isinstance(a, ParametricType):
if len(a.params) != len(b.params):
return f"{a} != {b}"
old = sub
for x, y in zip(a.params, b.params):
old = find_subst(ctx, old, x, y)
@ -62,4 +63,86 @@ def find_subst(ctx: dict[str, Type],
raise Exception()
return f"{a} != {b}"
def resolve_call(obj,
fn: str,
args: list[Type],
assumptions: dict[str, Type],
ctx: Context) -> tuple[Type]:
# TODO: we may want to return the substitution, for monomorphization...
f_args = None
f_result = None
if obj is not None:
obj = obj.subst(assumptions)
if obj is None:
if fn in ctx.functions:
f = ctx.functions[fn]
f_args, f_result = TupleType(f[0]), f[1]
elif fn in ctx.types:
c = ctx.types[fn]
if '__init__' in c.methods:
f = c.methods['__init__']
if not isinstance(f[0][0], SelfType) or f[1] is not None:
raise CustomError(
f'__init__ of {c} should accept self and return None'
)
f_args, f_result = TupleType(f[0][1:]), c
else:
f_args, f_result = TupleType([]), c
else:
raise CustomError(f"No such function {fn}")
elif isinstance(obj, PrimitiveType) or isinstance(obj, ClassType):
if fn in obj.methods:
f = obj.methods[fn]
if len(f[0]) == 0 or (not isinstance(f[0][0], SelfType) and \
f[0][0] != obj):
raise CustomError('{f} is not a method of {obj}')
f_args, f_result = TupleType(f[0][1:]), f[1]
else:
raise CustomError(f"No such method {fn} in {c}")
elif isinstance(obj, VirtualClassType):
# may need to emit special annotation that this is a virtual method
# call?
if fn in obj.base.methods:
f = obj.base.methods[fn]
if len(f[0]) == 0 or not isinstance(f[0][0], SelfType):
raise CustomError('{f} is not a method of {obj}')
f_args, f_result = TupleType(f[0][1:]), f[1]
else:
raise CustomError(f"No such method {fn} in {c}")
elif isinstance(obj, TypeVariable):
# if not constrained, error. otherwise, try all values, and only allow
# if the results are the same or if they are the same modulo the
# substitution.
# expensive operation, but cache should be applicable
# in order to cache this, our cache must be able to compare equality
# modulo variable naming... probably not easy either
if len(obj.constraints) == 0:
raise CustomError("no methods for unconstrained object")
results = [resolve_call(obj, fn, args, assumptions | {obj.name: v}, ctx)
for v in obj.assumptions]
for v in results[1:]:
if v != results[0]:
break
else:
# same result
return results[0]
results = [v.inv_subst([a, obj])
for v, a in zip(results, obj.assumptions)]
for v in results[1:]:
if v != results[0]:
break
else:
# same result
return results[0]
raise CustomError("Divergent type after constraints substitution")
a = TupleType(args)
subst = find_subst(assumptions, {}, a, f_args)
if isinstance(subst, str):
raise CustomError(f"type check failed: {subst}")
result = f_result.subst(subst)
if isinstance(result, SelfType):
return obj
else:
return result

60
toy-impl/test_inference.py Normal file
View File

@ -0,0 +1,60 @@
from type_def import *
from inference import *
from helper import *
types = {
'int32': PrimitiveType('int32'),
'int64': PrimitiveType('int64'),
'str': PrimitiveType('str'),
}
i32 = types['int32']
i64 = types['int64']
s = types['str']
variables = {
'X': TypeVariable('X', []),
'Y': TypeVariable('Y', []),
'I': TypeVariable('I', [i32, i64]),
'A': TypeVariable('A', [i32, i64, s]),
}
X = variables['X']
Y = variables['Y']
I = variables['I']
A = variables['A']
i32.methods['__init__'] = ([SelfType(), I], None, set())
i32.methods['__add__'] = ([SelfType(), i32], i32, set())
i32.methods['__sub__'] = ([SelfType(), i32], i32, set())
i64.methods['__init__'] = ([SelfType(), I], None, set())
i64.methods['__add__'] = ([SelfType(), i64], i64, set())
i64.methods['__sub__'] = ([SelfType(), i64], i64, set())
ctx = Context(variables, types)
def test_call(obj, fn, args, assumptions = {}):
args_str = ', '.join([str(v) for v in args])
obj_str = '' if obj is None else str(obj) + '.'
print(f'Testing {obj_str}{fn}({args_str}) w.r.t. {stringify_subst(assumptions)}')
try:
result = resolve_call(obj, fn, args, assumptions, ctx)
print(result)
except CustomError as err:
print(f'error: {err.msg}')
test_call(None, 'int32', [])
test_call(None, 'int32', [i32])
test_call(None, 'int32', [i64])
test_call(None, 'int32', [I])
test_call(None, 'int32', [A])
test_call(None, 'int32', [i32, i64])
test_call(i32, '__add__', [])
test_call(i32, '__add__', [i32])
test_call(i32, '__add__', [i64])
test_call(i32, '__add__', [i32, i32])

3
toy-impl/test_subst.py
View File

@ -1,5 +1,6 @@
from type_def import *
from inference import *
from helper import *
types = {
'int32': PrimitiveType('int32'),
@ -49,6 +50,7 @@ try_case(A, I, {})
try_case(X, I, {})
try_case(ListType(i32), TupleType([i32]), {})
try_case(TupleType([i32]), ListType(i32), {})
try_case(TupleType([i32, i32]), TupleType([i32]), {})
try_case(ListType(i32), ListType(i32), {})
try_case(TupleType([X, X]), TupleType([X, Y]), {})
try_case(TupleType([X, X]), TupleType([Y, Y]), {})
@ -57,4 +59,3 @@ try_case(TupleType([X, X]), TupleType([X, X]), {})
try_case(TupleType([X, Y]), X, {})
try_case(TupleType([i32, Y]), X, {})

4
toy-impl/test_top_level.py
View File

@ -10,7 +10,7 @@ class A:
class B(A):
a: str
def bar(a: list[list[virtual[A]]]) -> A:
def bar(self, a: list[list[virtual[A]]]) -> self:
pass
"""
@ -18,7 +18,7 @@ variables = {'X': TypeVariable('X', []), 'Y': TypeVariable('Y', [])}
types = {'int': PrimitiveType('int'), 'str': PrimitiveType('str')}
ctx = Context(variables, types)
ctx, functions, _ = parse_top_level(ctx, ast.parse(test))
ctx, _ = parse_top_level(ctx, ast.parse(test))
for name, t in ctx.types.items():
if isinstance(t, ClassType):

28
toy-impl/top_level.py
View File

@ -1,17 +1,6 @@
import ast
from type_def import *
class CustomError(Exception):
def __init__(self, msg):
self.msg = msg
class Context:
variables: dict[str, TypeVariable]
types: dict[Type]
def __init__(self, variables, types):
self.variables = variables
self.types = types
from helper import *
def parse_type(ctx: Context, ty):
@ -65,9 +54,13 @@ def parse_function(ctx: Context, base, fn: ast.FunctionDef):
ty, v = parse_type(ctx, arg.annotation)
var |= v
if name == 'self' and ty is None and base is not None:
ty = base
ty = SelfType()
args.append(ty)
result, v = parse_type(ctx, fn.returns)
if isinstance(fn.returns, ast.Name) and fn.returns.id == 'self'\
and base is not None:
result, v = SelfType(), set()
else:
result, v = parse_type(ctx, fn.returns)
if len(v - var) > 0:
raise CustomError(f"Unbounded variable in return type of {fn.name}")
return args, result, var
@ -126,7 +119,6 @@ def parse_top_level(ctx: Context, module: ast.Module):
to_be_processed.append(element)
# second pass, obtain all function types
functions = {}
function_stmts = []
for element in to_be_processed:
if isinstance(element, ast.ClassDef):
@ -135,10 +127,12 @@ def parse_top_level(ctx: Context, module: ast.Module):
name = element.name
if name in functions:
raise CustomError(f"Duplicated function name {name}")
if name in ctx.types:
raise CustomError(f"Function name {name} clashed with type name")
args, result, var = parse_function(ctx, None, element)
functions[name] = (args, result, var)
ctx.functions[name] = (args, result, var)
function_stmts += element
return ctx, functions, function_stmts
return ctx, function_stmts

59
toy-impl/type_def.py
View File

@ -1,10 +1,28 @@
import copy
class Type:
methods: dict[str, tuple[list['Type'], 'Type', set[str]]]
fields: dict[str, 'Type']
def __init__(self):
self.methods = {}
self.fields = {}
def __eq__(self, other):
return False
def get_vars(self):
return []
def subst(self, subst: dict[str, 'Type']):
return self
def inv_subst(self, subst: list[tuple['Type', 'TypeVariable']]):
for t, tv in subst:
if self == t:
return tv
return self
class BotType:
def __eq__(self, other):
@ -15,6 +33,7 @@ class PrimitiveType(Type):
name: str
def __init__(self, name: str):
super().__init__()
self.name = name
def __str__(self):
@ -32,6 +51,7 @@ class TypeVariable(Type):
constraints: list[Type]
def __init__(self, name: str, constraints: list[Type]):
super().__init__()
self.name = name
self.constraints = constraints
@ -44,6 +64,11 @@ class TypeVariable(Type):
def get_vars(self):
return [self]
def subst(self, subst: dict[str, Type]):
if self.name in subst:
return subst[self.name]
return self
class ClassType(Type):
name: str
@ -52,10 +77,9 @@ class ClassType(Type):
fields: dict[str, Type]
def __init__(self, name: str):
super().__init__()
self.name = name
self.parents = []
self.methods = {}
self.fields = {}
def __str__(self):
return self.name
@ -63,10 +87,17 @@ class ClassType(Type):
def __eq__(self, other):
return isinstance(other, ClassType) and self.name == other.name
class SelfType(Type):
def __str__(self):
return 'self'
class VirtualClassType(Type):
base: ClassType
def __init__(self, base: ClassType):
super().__init__()
self.base = base
def __str__(self):
@ -79,6 +110,7 @@ class ParametricType(Type):
params: list[Type]
def __init__(self, params: list[Type]):
super().__init__()
self.params = params
def __eq__(self, other):
@ -98,6 +130,19 @@ class ParametricType(Type):
result.append(v)
return result
def subst(self, subst: dict[str, Type]):
s = copy.copy(self)
s.params = [v.subst(subst) for v in self.params]
return s
def inv_subst(self, subst: list[tuple['Type', 'TypeVariable']]):
for t, tv in subst:
if self == t:
return tv
s = copy.copy(self)
s.params = [v.inv_subst(subst) for v in self.params]
return s
class ListType(ParametricType):
def __init__(self, param: Type):
super().__init__([param])
@ -114,3 +159,13 @@ class TupleType(ParametricType):
return f"tuple[{', '.join([str(v) for v in self.params])}]"
class Context:
variables: dict[str, TypeVariable]
types: dict[str, Type]
functions: dict[str, tuple[list[Type], Type, set[str]]]
def __init__(self, variables, types):
self.variables = variables
self.types = types
self.functions = {}