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] = []) -> (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)