def mutate(e: syntax.Exp, op: syntax.Stm) -> syntax.Exp:
"""Return the new value of `e` after executing `op`."""
if isinstance(op, syntax.SNoOp):
return e
elif isinstance(op, syntax.SAssign):
return _do_assignment(op.lhs, op.rhs, e)
elif isinstance(op, syntax.SCall):
if op.func == "add":
return mutate(
e,
syntax.SCall(op.target, "add_all", (syntax.ESingleton(
op.args[0]).with_type(op.target.type), )))
elif op.func == "add_all":
return mutate(
e,
syntax.SAssign(
op.target,
syntax.EBinOp(op.target, "+",
op.args[0]).with_type(op.target.type)))
elif op.func == "remove":
return mutate(
e,
syntax.SCall(op.target, "remove_all", (syntax.ESingleton(
op.args[0]).with_type(op.target.type), )))
elif op.func == "remove_all":
return mutate(
e,
syntax.SAssign(
op.target,
syntax.EBinOp(op.target, "-",
op.args[0]).with_type(op.target.type)))
else:
raise Exception("Unknown func: {}".format(op.func))
elif isinstance(op, syntax.SIf):
then_branch = mutate(e, op.then_branch)
else_branch = mutate(e, op.else_branch)
if alpha_equivalent(then_branch, else_branch):
return then_branch
return syntax.ECond(op.cond, then_branch,
else_branch).with_type(e.type)
elif isinstance(op, syntax.SSeq):
if isinstance(op.s1, syntax.SSeq):
return mutate(e, syntax.SSeq(op.s1.s1,
syntax.SSeq(op.s1.s2, op.s2)))
e2 = mutate(mutate(e, op.s2), op.s1)
if isinstance(op.s1, syntax.SDecl):
e2 = subst(e2, {op.s1.id: op.s1.val})
return e2
elif isinstance(op, syntax.SDecl):
return e
else:
raise NotImplementedError(type(op))
def _fix_map(m: target_syntax.EMap) -> syntax.Exp:
return m
from cozy.simplification import simplify
m = simplify(m)
if not isinstance(m, target_syntax.EMap):
return m
elem_type = m.e.type.t
assert m.f.body.type == elem_type
changed = target_syntax.EFilter(
m.e,
mk_lambda(
elem_type, lambda x: syntax.ENot(
syntax.EBinOp(x, "===", m.f.apply_to(x)).with_type(syntax.BOOL)
))).with_type(m.e.type)
e = syntax.EBinOp(
syntax.EBinOp(m.e, "-", changed).with_type(m.e.type), "+",
target_syntax.EMap(changed,
m.f).with_type(m.e.type)).with_type(m.e.type)
if not valid(syntax.EEq(m, e)):
print("WARNING: rewrite failed")
print("_fix_map({!r})".format(m))
return m
return e
def p_exp(p):
"""exp : NUM
| FLOAT
| WORD
| WORD OP_OPEN_PAREN exp_list OP_CLOSE_PAREN
| KW_TRUE
| KW_FALSE
| exp OP_PLUS exp
| exp OP_MINUS exp
| exp OP_TIMES exp
| exp OP_EQ exp
| exp OP_NE exp
| exp OP_LT exp
| exp OP_LE exp
| exp OP_GT exp
| exp OP_GE exp
| exp KW_AND exp
| exp KW_OR exp
| exp OP_IMPLIES exp
| exp OP_QUESTION exp OP_COLON exp
| exp OP_OPEN_BRACKET slice OP_CLOSE_BRACKET
| KW_NOT exp
| OP_MINUS exp
| exp KW_IN exp
| KW_UNIQUE exp
| KW_DISTINCT exp
| KW_EMPTY exp
| KW_THE exp
| KW_MIN exp
| KW_MAX exp
| KW_ARGMIN lambda exp
| KW_ARGMAX lambda exp
| KW_SUM exp
| KW_LEN exp
| KW_ANY exp
| KW_ALL exp
| KW_EXISTS exp
| KW_REVERSED exp
| exp OP_DOT NUM
| exp OP_DOT WORD
| OP_OPEN_PAREN exp_list OP_CLOSE_PAREN
| OP_OPEN_BRACE record_fields OP_CLOSE_BRACE
| OP_OPEN_BRACKET exp OP_CLOSE_BRACKET
| OP_OPEN_BRACKET exp OP_VBAR comprehension_body OP_CLOSE_BRACKET"""
if len(p) == 2:
if type(p[1]) is syntax.ENum:
p[0] = p[1]
elif p[1] == "true":
p[0] = syntax.EBool(True)
elif p[1] == "false":
p[0] = syntax.EBool(False)
else:
p[0] = syntax.EVar(p[1])
elif len(p) == 3:
if p[1] == "min":
p[0] = syntax.EArgMin(
p[2], syntax.ELambda(syntax.EVar("x"), syntax.EVar("x")))
elif p[1] == "max":
p[0] = syntax.EArgMax(
p[2], syntax.ELambda(syntax.EVar("x"), syntax.EVar("x")))
else:
p[0] = syntax.EUnaryOp(p[1], p[2])
elif len(p) == 4:
if p[1] == "(":
exps = p[2]
if len(exps) == 0:
raise Exception("illegal ()")
elif len(exps) == 1:
p[0] = exps[0]
elif len(exps) > 1:
p[0] = syntax.ETuple(tuple(exps))
elif p[1] == "[":
p[0] = syntax.ESingleton(p[2])
elif p[1] == "{":
p[0] = syntax.EMakeRecord(p[2])
elif p[2] == ".":
if isinstance(p[3], syntax.ENum):
p[0] = syntax.ETupleGet(p[1], p[3].val)
else:
p[0] = syntax.EGetField(p[1], p[3])
elif p[1] == "argmin":
p[0] = syntax.EArgMin(p[3], p[2])
elif p[1] == "argmax":
p[0] = syntax.EArgMax(p[3], p[2])
else:
p[0] = syntax.EBinOp(p[1], p[2], p[3])
else:
if p[2] == "?":
p[0] = syntax.ECond(p[1], p[3], p[5])
elif p[2] == "[":
if isinstance(p[3], syntax.Exp):
p[0] = syntax.EListGet(p[1], p[3])
elif isinstance(p[3], tuple):
start = p[3][0]
end = p[3][1]
if start is None:
start = syntax.ZERO
if end is None:
end = syntax.ELen(p[1])
p[0] = syntax.EListSlice(p[1], start, end)
elif p[1] == "[":
p[0] = syntax.EListComprehension(p[2], p[4])
elif p[2] == "(":
p[0] = syntax.ECall(p[1], p[3])
else:
assert False, "unknown case: {}".format(repr(p[1:]))
def sketch_update(
lval: syntax.Exp,
old_value: syntax.Exp,
new_value: syntax.Exp,
ctx: [syntax.EVar],
assumptions: [syntax.Exp] = [],
invariants: [syntax.Exp] = []) -> (syntax.Stm, [syntax.Query]):
"""
Write code to update `lval` when it changes from `old_value` to `new_value`.
Variables in `ctx` are assumed to be part of the data structure abstract
state, and `assumptions` will be appended to all generated subgoals.
This function returns a statement (code to update `lval`) and a list of
subgoals (new queries that appear in the code).
"""
if valid(
syntax.EImplies(
syntax.EAll(itertools.chain(assumptions, invariants)),
syntax.EEq(old_value, new_value))):
return (syntax.SNoOp(), [])
subgoals = []
new_value = strip_EStateVar(new_value)
def make_subgoal(e, a=[], docstring=None):
if skip_stateless_synthesis.value and not any(v in ctx
for v in free_vars(e)):
return e
query_name = fresh_name("query")
query = syntax.Query(query_name, syntax.Visibility.Internal, [],
assumptions + a, e, docstring)
query_vars = [v for v in free_vars(query) if v not in ctx]
query.args = [(arg.id, arg.type) for arg in query_vars]
subgoals.append(query)
return syntax.ECall(query_name, tuple(query_vars)).with_type(e.type)
def recurse(*args, **kwargs):
(code, sgs) = sketch_update(*args, **kwargs)
subgoals.extend(sgs)
return code
t = lval.type
if isinstance(t, syntax.TBag) or isinstance(t, syntax.TSet):
to_add = make_subgoal(syntax.EBinOp(new_value, "-",
old_value).with_type(t),
docstring="additions to {}".format(pprint(lval)))
to_del = make_subgoal(
syntax.EBinOp(old_value, "-", new_value).with_type(t),
docstring="deletions from {}".format(pprint(lval)))
v = fresh_var(t.t)
stm = syntax.seq([
syntax.SForEach(v, to_del, syntax.SCall(lval, "remove", [v])),
syntax.SForEach(v, to_add, syntax.SCall(lval, "add", [v]))
])
elif is_numeric(t) and update_numbers_with_deltas.value:
change = make_subgoal(syntax.EBinOp(new_value, "-",
old_value).with_type(t),
docstring="delta for {}".format(pprint(lval)))
stm = syntax.SAssign(lval,
syntax.EBinOp(lval, "+", change).with_type(t))
elif isinstance(t, syntax.TTuple):
get = lambda val, i: syntax.ETupleGet(val, i).with_type(t.ts[i])
stm = syntax.seq([
recurse(get(lval, i),
get(old_value, i),
get(new_value, i),
ctx,
assumptions,
invariants=invariants) for i in range(len(t.ts))
])
elif isinstance(t, syntax.TRecord):
get = lambda val, i: syntax.EGetField(val, t.fields[i][0]).with_type(
t.fields[i][1])
stm = syntax.seq([
recurse(get(lval, i),
get(old_value, i),
get(new_value, i),
ctx,
assumptions,
invariants=invariants) for i in range(len(t.fields))
])
elif isinstance(t, syntax.TMap):
k = fresh_var(lval.type.k)
v = fresh_var(lval.type.v)
key_bag = syntax.TBag(lval.type.k)
old_keys = target_syntax.EMapKeys(old_value).with_type(key_bag)
new_keys = target_syntax.EMapKeys(new_value).with_type(key_bag)
# (1) exit set
deleted_keys = syntax.EBinOp(old_keys, "-",
new_keys).with_type(key_bag)
s1 = syntax.SForEach(
k,
make_subgoal(deleted_keys,
docstring="keys removed from {}".format(
pprint(lval))), target_syntax.SMapDel(lval, k))
# (2) enter/mod set
new_or_modified = target_syntax.EFilter(
new_keys,
syntax.ELambda(
k,
syntax.EAny([
syntax.ENot(syntax.EIn(k, old_keys)),
syntax.ENot(
syntax.EEq(value_at(old_value, k),
value_at(new_value, k)))
]))).with_type(key_bag)
update_value = recurse(v,
value_at(old_value, k),
value_at(new_value, k),
ctx=ctx,
assumptions=assumptions + [
syntax.EIn(k, new_or_modified),
syntax.EEq(v, value_at(old_value, k))
],
invariants=invariants)
s2 = syntax.SForEach(
k,
make_subgoal(new_or_modified,
docstring="new or modified keys from {}".format(
pprint(lval))),
target_syntax.SMapUpdate(lval, k, v, update_value))
stm = syntax.SSeq(s1, s2)
else:
# Fallback rule: just compute a new value from scratch
stm = syntax.SAssign(
lval,
make_subgoal(new_value,
docstring="new value for {}".format(pprint(lval))))
return (stm, subgoals)
def _delta_form(res: {str: syntax.Exp}, op: syntax.Stm) -> {str: syntax.Exp}:
if isinstance(op, syntax.SNoOp):
pass
elif isinstance(op, syntax.SCall):
update = _rewriter(op.target)
if op.func == "add":
update(
res, lambda old: syntax.EBinOp(
old, "+",
syntax.ESingleton(op.args[0]).with_type(old.type)).
with_type(old.type))
elif op.func == "add_back":
update(
res, lambda old: syntax.EBinOp(
old, "+",
syntax.ESingleton(op.args[0]).with_type(old.type)).
with_type(old.type))
elif op.func == "add_front":
update(
res, lambda old: syntax.EBinOp(
syntax.ESingleton(op.args[0]).with_type(old.type), "+", old
).with_type(old.type))
elif op.func == "remove_back":
update(
res,
lambda old: target_syntax.EDropBack(old).with_type(old.type))
elif op.func == "remove_front":
update(
res,
lambda old: target_syntax.EDropFront(old).with_type(old.type))
elif op.func == "remove":
update(
res, lambda old: syntax.EBinOp(
old, "-",
syntax.ESingleton(op.args[0]).with_type(old.type)).
with_type(old.type))
elif op.func == "remove_all":
update(
res, lambda old: syntax.EBinOp(old, "-", op.args[0]).with_type(
old.type))
else:
raise Exception("Unknown func: {}".format(op.func))
elif isinstance(op, syntax.SAssign):
update = _rewriter(op.lhs)
update(res, lambda old: op.rhs)
elif isinstance(op, syntax.SIf):
res_then = res.copy()
_delta_form(res_then, op.then_branch)
res_else = res.copy()
_delta_form(res_else, op.else_branch)
for key in res:
then_val = res_then[key]
else_val = res_else[key]
if then_val == else_val:
res[key] = then_val
else:
# Substatements differ; need to defer to ECond evaluation.
res[key] = syntax.ECond(op.cond, then_val,
else_val).with_type(then_val.type)
elif isinstance(op, syntax.SSeq):
_delta_form(res, op.s1)
_delta_form(res, subst(op.s2, res))
else:
raise NotImplementedError(type(op))
return res
def sketch_update(
lval: syntax.Exp,
old_value: syntax.Exp,
new_value: syntax.Exp,
ctx: [syntax.EVar],
assumptions: [syntax.Exp] = []) -> (syntax.Stm, [syntax.Query]):
"""
Write code to update `lval` when it changes from `old_value` to `new_value`.
Variables in `ctx` are assumed to be part of the data structure abstract
state, and `assumptions` will be appended to all generated subgoals.
This function returns a statement (code to update `lval`) and a list of
subgoals (new queries that appear in the code).
"""
if valid(
syntax.EImplies(syntax.EAll(assumptions),
syntax.EEq(old_value, new_value))):
return (syntax.SNoOp(), [])
subgoals = []
def make_subgoal(e, a=[], docstring=None):
e = strip_EStateVar(e)
if skip_stateless_synthesis.value and not any(v in ctx
for v in free_vars(e)):
return e
query_name = fresh_name("query")
query = syntax.Query(query_name, syntax.Visibility.Internal, [],
assumptions + a, e, docstring)
query_vars = [v for v in free_vars(query) if v not in ctx]
query.args = [(arg.id, arg.type) for arg in query_vars]
subgoals.append(query)
return syntax.ECall(query_name, tuple(query_vars)).with_type(e.type)
def recurse(*args, **kwargs):
(code, sgs) = sketch_update(*args, **kwargs)
subgoals.extend(sgs)
return code
t = lval.type
if isinstance(t, syntax.TBag) or isinstance(t, syntax.TSet):
to_add = make_subgoal(syntax.EBinOp(new_value, "-",
old_value).with_type(t),
docstring="additions to {}".format(pprint(lval)))
to_del = make_subgoal(
syntax.EBinOp(old_value, "-", new_value).with_type(t),
docstring="deletions from {}".format(pprint(lval)))
v = fresh_var(t.t)
stm = syntax.seq([
syntax.SForEach(v, to_del, syntax.SCall(lval, "remove", [v])),
syntax.SForEach(v, to_add, syntax.SCall(lval, "add", [v]))
])
# elif isinstance(t, syntax.TList):
# raise NotImplementedError()
elif is_numeric(t):
change = make_subgoal(syntax.EBinOp(new_value, "-",
old_value).with_type(t),
docstring="delta for {}".format(pprint(lval)))
stm = syntax.SAssign(lval,
syntax.EBinOp(lval, "+", change).with_type(t))
elif isinstance(t, syntax.TTuple):
get = lambda val, i: syntax.ETupleGet(val, i).with_type(t.ts[i])
stm = syntax.seq([
recurse(get(lval, i), get(old_value, i), get(new_value, i), ctx,
assumptions) for i in range(len(t.ts))
])
elif isinstance(t, syntax.TRecord):
get = lambda val, i: syntax.EGetField(val, t.fields[i][0]).with_type(
t.fields[i][1])
stm = syntax.seq([
recurse(get(lval, i), get(old_value, i), get(new_value, i), ctx,
assumptions) for i in range(len(t.fields))
])
elif isinstance(t, syntax.THandle):
# handles are tricky, and are dealt with at a higher level
stm = syntax.SNoOp()
elif isinstance(t, syntax.TMap):
value_at = lambda m, k: target_syntax.EMapGet(m, k).with_type(lval.type
.v)
k = fresh_var(lval.type.k)
v = fresh_var(lval.type.v)
key_bag = syntax.TBag(lval.type.k)
if True:
old_keys = target_syntax.EMapKeys(old_value).with_type(key_bag)
new_keys = target_syntax.EMapKeys(new_value).with_type(key_bag)
# (1) exit set
deleted_keys = target_syntax.EFilter(
old_keys,
target_syntax.ELambda(k, syntax.ENot(syntax.EIn(
k, new_keys)))).with_type(key_bag)
s1 = syntax.SForEach(
k,
make_subgoal(deleted_keys,
docstring="keys removed from {}".format(
pprint(lval))),
target_syntax.SMapDel(lval, k))
# (2) modify set
common_keys = target_syntax.EFilter(
old_keys,
target_syntax.ELambda(k,
syntax.EIn(k,
new_keys))).with_type(key_bag)
update_value = recurse(v,
value_at(old_value, k),
value_at(new_value, k),
ctx=ctx,
assumptions=assumptions + [
syntax.EIn(k, common_keys),
syntax.ENot(
syntax.EEq(value_at(old_value, k),
value_at(new_value, k)))
])
altered_keys = target_syntax.EFilter(
common_keys,
target_syntax.ELambda(
k,
syntax.ENot(
syntax.EEq(value_at(old_value, k),
value_at(new_value,
k))))).with_type(key_bag)
s2 = syntax.SForEach(
k,
make_subgoal(altered_keys,
docstring="altered keys in {}".format(
pprint(lval))),
target_syntax.SMapUpdate(lval, k, v, update_value))
# (3) enter set
fresh_keys = target_syntax.EFilter(
new_keys,
target_syntax.ELambda(k, syntax.ENot(syntax.EIn(
k, old_keys)))).with_type(key_bag)
s3 = syntax.SForEach(
k,
make_subgoal(fresh_keys,
docstring="new keys in {}".format(pprint(lval))),
target_syntax.SMapPut(
lval, k,
make_subgoal(value_at(new_value, k),
a=[syntax.EIn(k, fresh_keys)],
docstring="new value inserted at {}".format(
pprint(target_syntax.EMapGet(lval, k))))))
stm = syntax.seq([s1, s2, s3])
else:
# update_value = code to update for value v at key k (given that k is an altered key)
update_value = recurse(v,
value_at(old_value, k),
value_at(new_value, k),
ctx=ctx,
assumptions=assumptions + [
syntax.ENot(
syntax.EEq(value_at(old_value, k),
value_at(new_value, k)))
])
# altered_keys = [k | k <- distinct(lval.keys() + new_value.keys()), value_at(old_value, k) != value_at(new_value, k))]
altered_keys = make_subgoal(
target_syntax.EFilter(
syntax.EUnaryOp(
syntax.UOp.Distinct,
syntax.EBinOp(
target_syntax.EMapKeys(old_value).with_type(
key_bag), "+",
target_syntax.EMapKeys(new_value).with_type(
key_bag)).with_type(key_bag)).with_type(
key_bag),
target_syntax.ELambda(
k,
syntax.ENot(
syntax.EEq(value_at(old_value, k),
value_at(new_value,
k))))).with_type(key_bag))
stm = syntax.SForEach(
k, altered_keys,
target_syntax.SMapUpdate(lval, k, v, update_value))
else:
# Fallback rule: just compute a new value from scratch
stm = syntax.SAssign(
lval,
make_subgoal(new_value,
docstring="new value for {}".format(pprint(lval))))
return (stm, subgoals)