[rustc.git] / src / etc / gdb_providers.py

from sys import version_info

import gdb
from gdb import lookup_type

if version_info[0] >= 3:
    xrange = range

ZERO_FIELD = "__0"
FIRST_FIELD = "__1"


def unwrap_unique_or_non_null(unique_or_nonnull):
    # BACKCOMPAT: rust 1.32
    # https://github.com/rust-lang/rust/commit/7a0911528058e87d22ea305695f4047572c5e067
    ptr = unique_or_nonnull["pointer"]
    return ptr if ptr.type.code == gdb.TYPE_CODE_PTR else ptr[ZERO_FIELD]


class EnumProvider:
    def __init__(self, valobj):
        content = valobj[valobj.type.fields()[0]]
        fields = content.type.fields()
        self.empty = len(fields) == 0
        if not self.empty:
            if len(fields) == 1:
                discriminant = 0
            else:
                discriminant = int(content[fields[0]]) + 1
            self.active_variant = content[fields[discriminant]]
            self.name = fields[discriminant].name
            self.full_name = "{}::{}".format(valobj.type.name, self.name)
        else:
            self.full_name = valobj.type.name

    def to_string(self):
        return self.full_name

    def children(self):
        if not self.empty:
            yield self.name, self.active_variant


class StdStringProvider:
    def __init__(self, valobj):
        self.valobj = valobj
        vec = valobj["vec"]
        self.length = int(vec["len"])
        self.data_ptr = unwrap_unique_or_non_null(vec["buf"]["ptr"])

    def to_string(self):
        return self.data_ptr.lazy_string(encoding="utf-8", length=self.length)

    @staticmethod
    def display_hint():
        return "string"


class StdOsStringProvider:
    def __init__(self, valobj):
        self.valobj = valobj
        buf = self.valobj["inner"]["inner"]
        is_windows = "Wtf8Buf" in buf.type.name
        vec = buf[ZERO_FIELD] if is_windows else buf

        self.length = int(vec["len"])
        self.data_ptr = unwrap_unique_or_non_null(vec["buf"]["ptr"])

    def to_string(self):
        return self.data_ptr.lazy_string(encoding="utf-8", length=self.length)

    def display_hint(self):
        return "string"


class StdStrProvider:
    def __init__(self, valobj):
        self.valobj = valobj
        self.length = int(valobj["length"])
        self.data_ptr = valobj["data_ptr"]

    def to_string(self):
        return self.data_ptr.lazy_string(encoding="utf-8", length=self.length)

    @staticmethod
    def display_hint():
        return "string"


class StdVecProvider:
    def __init__(self, valobj):
        self.valobj = valobj
        self.length = int(valobj["len"])
        self.data_ptr = unwrap_unique_or_non_null(valobj["buf"]["ptr"])

    def to_string(self):
        return "Vec(size={})".format(self.length)

    def children(self):
        saw_inaccessible = False
        for index in xrange(self.length):
            element_ptr = self.data_ptr + index
            if saw_inaccessible:
                return
            try:
                # rust-lang/rust#64343: passing deref expr to `str` allows
                # catching exception on garbage pointer
                str(element_ptr.dereference())
                yield "[{}]".format(index), element_ptr.dereference()
            except RuntimeError:
                saw_inaccessible = True
                yield str(index), "inaccessible"

    @staticmethod
    def display_hint():
        return "array"


class StdVecDequeProvider:
    def __init__(self, valobj):
        self.valobj = valobj
        self.head = int(valobj["head"])
        self.tail = int(valobj["tail"])
        self.cap = int(valobj["buf"]["cap"])
        self.data_ptr = unwrap_unique_or_non_null(valobj["buf"]["ptr"])
        if self.head >= self.tail:
            self.size = self.head - self.tail
        else:
            self.size = self.cap + self.head - self.tail

    def to_string(self):
        return "VecDeque(size={})".format(self.size)

    def children(self):
        for index in xrange(0, self.size):
            value = (self.data_ptr + ((self.tail + index) % self.cap)).dereference()
            yield "[{}]".format(index), value

    @staticmethod
    def display_hint():
        return "array"


class StdRcProvider:
    def __init__(self, valobj, is_atomic=False):
        self.valobj = valobj
        self.is_atomic = is_atomic
        self.ptr = unwrap_unique_or_non_null(valobj["ptr"])
        self.value = self.ptr["data" if is_atomic else "value"]
        self.strong = self.ptr["strong"]["v" if is_atomic else "value"]["value"]
        self.weak = self.ptr["weak"]["v" if is_atomic else "value"]["value"] - 1

    def to_string(self):
        if self.is_atomic:
            return "Arc(strong={}, weak={})".format(int(self.strong), int(self.weak))
        else:
            return "Rc(strong={}, weak={})".format(int(self.strong), int(self.weak))

    def children(self):
        yield "value", self.value
        yield "strong", self.strong
        yield "weak", self.weak


class StdCellProvider:
    def __init__(self, valobj):
        self.value = valobj["value"]["value"]

    def to_string(self):
        return "Cell"

    def children(self):
        yield "value", self.value


class StdRefProvider:
    def __init__(self, valobj):
        self.value = valobj["value"].dereference()
        self.borrow = valobj["borrow"]["borrow"]["value"]["value"]

    def to_string(self):
        borrow = int(self.borrow)
        if borrow >= 0:
            return "Ref(borrow={})".format(borrow)
        else:
            return "Ref(borrow_mut={})".format(-borrow)

    def children(self):
        yield "*value", self.value
        yield "borrow", self.borrow


class StdRefCellProvider:
    def __init__(self, valobj):
        self.value = valobj["value"]["value"]
        self.borrow = valobj["borrow"]["value"]["value"]

    def to_string(self):
        borrow = int(self.borrow)
        if borrow >= 0:
            return "RefCell(borrow={})".format(borrow)
        else:
            return "RefCell(borrow_mut={})".format(-borrow)

    def children(self):
        yield "value", self.value
        yield "borrow", self.borrow


# Yield each key (and optionally value) from a BoxedNode.
def children_of_node(boxed_node, height, want_values):
    def cast_to_internal(node):
        internal_type_name = str(node.type.target()).replace("LeafNode", "InternalNode", 1)
        internal_type = lookup_type(internal_type_name)
        return node.cast(internal_type.pointer())

    node_ptr = unwrap_unique_or_non_null(boxed_node["ptr"])
    node_ptr = cast_to_internal(node_ptr) if height > 0 else node_ptr
    leaf = node_ptr["data"] if height > 0 else node_ptr.dereference()
    keys = leaf["keys"]
    values = leaf["vals"]
    length = int(leaf["len"])

    for i in xrange(0, length + 1):
        if height > 0:
            child_ptr = node_ptr["edges"][i]["value"]["value"]
            for child in children_of_node(child_ptr, height - 1, want_values):
                yield child
        if i < length:
            if want_values:
                yield keys[i]["value"]["value"], values[i]["value"]["value"]
            else:
                yield keys[i]["value"]["value"]


class StdBTreeSetProvider:
    def __init__(self, valobj):
        self.valobj = valobj

    def to_string(self):
        return "BTreeSet(size={})".format(self.valobj["map"]["length"])

    def children(self):
        inner_map = self.valobj["map"]
        if inner_map["length"] > 0:
            root = inner_map["root"]
            if "core::option::Option<" in root.type.name:
                type_name = str(root.type.name).replace("core::option::Option<", "", 1)[:-1]
                root = root.cast(gdb.lookup_type(type_name))

            node_ptr = root["node"]
            for i, child in enumerate(children_of_node(node_ptr, root["height"], False)):
                yield "[{}]".format(i), child

    @staticmethod
    def display_hint():
        return "array"


class StdBTreeMapProvider:
    def __init__(self, valobj):
        self.valobj = valobj

    def to_string(self):
        return "BTreeMap(size={})".format(self.valobj["length"])

    def children(self):
        if self.valobj["length"] > 0:
            root = self.valobj["root"]
            if "core::option::Option<" in root.type.name:
                type_name = str(root.type.name).replace("core::option::Option<", "", 1)[:-1]
                root = root.cast(gdb.lookup_type(type_name))

            node_ptr = root["node"]
            for i, child in enumerate(children_of_node(node_ptr, root["height"], True)):
                yield "key{}".format(i), child[0]
                yield "val{}".format(i), child[1]

    @staticmethod
    def display_hint():
        return "map"


# BACKCOMPAT: rust 1.35
class StdOldHashMapProvider:
    def __init__(self, valobj, show_values=True):
        self.valobj = valobj
        self.show_values = show_values

        self.table = self.valobj["table"]
        self.size = int(self.table["size"])
        self.hashes = self.table["hashes"]
        self.hash_uint_type = self.hashes.type
        self.hash_uint_size = self.hashes.type.sizeof
        self.modulo = 2 ** self.hash_uint_size
        self.data_ptr = self.hashes[ZERO_FIELD]["pointer"]

        self.capacity_mask = int(self.table["capacity_mask"])
        self.capacity = (self.capacity_mask + 1) % self.modulo

        marker = self.table["marker"].type
        self.pair_type = marker.template_argument(0)
        self.pair_type_size = self.pair_type.sizeof

        self.valid_indices = []
        for idx in range(self.capacity):
            data_ptr = self.data_ptr.cast(self.hash_uint_type.pointer())
            address = data_ptr + idx
            hash_uint = address.dereference()
            hash_ptr = hash_uint[ZERO_FIELD]["pointer"]
            if int(hash_ptr) != 0:
                self.valid_indices.append(idx)

    def to_string(self):
        if self.show_values:
            return "HashMap(size={})".format(self.size)
        else:
            return "HashSet(size={})".format(self.size)

    def children(self):
        start = int(self.data_ptr) & ~1

        hashes = self.hash_uint_size * self.capacity
        align = self.pair_type_size
        len_rounded_up = (((((hashes + align) % self.modulo - 1) % self.modulo) & ~(
                (align - 1) % self.modulo)) % self.modulo - hashes) % self.modulo

        pairs_offset = hashes + len_rounded_up
        pairs_start = gdb.Value(start + pairs_offset).cast(self.pair_type.pointer())

        for index in range(self.size):
            table_index = self.valid_indices[index]
            idx = table_index & self.capacity_mask
            element = (pairs_start + idx).dereference()
            if self.show_values:
                yield "key{}".format(index), element[ZERO_FIELD]
                yield "val{}".format(index), element[FIRST_FIELD]
            else:
                yield "[{}]".format(index), element[ZERO_FIELD]

    def display_hint(self):
        return "map" if self.show_values else "array"


class StdHashMapProvider:
    def __init__(self, valobj, show_values=True):
        self.valobj = valobj
        self.show_values = show_values

        table = self.valobj["base"]["table"]
        capacity = int(table["bucket_mask"]) + 1
        ctrl = table["ctrl"]["pointer"]

        self.size = int(table["items"])
        self.pair_type = table.type.template_argument(0)

        self.new_layout = not table.type.has_key("data")
        if self.new_layout:
            self.data_ptr = ctrl.cast(self.pair_type.pointer())
        else:
            self.data_ptr = table["data"]["pointer"]

        self.valid_indices = []
        for idx in range(capacity):
            address = ctrl + idx
            value = address.dereference()
            is_presented = value & 128 == 0
            if is_presented:
                self.valid_indices.append(idx)

    def to_string(self):
        if self.show_values:
            return "HashMap(size={})".format(self.size)
        else:
            return "HashSet(size={})".format(self.size)

    def children(self):
        pairs_start = self.data_ptr

        for index in range(self.size):
            idx = self.valid_indices[index]
            if self.new_layout:
                idx = -(idx + 1)
            element = (pairs_start + idx).dereference()
            if self.show_values:
                yield "key{}".format(index), element[ZERO_FIELD]
                yield "val{}".format(index), element[FIRST_FIELD]
            else:
                yield "[{}]".format(index), element[ZERO_FIELD]

    def display_hint(self):
        return "map" if self.show_values else "array"
Commit	Line	Data
f035d41b XL	1	from sys import version_info
	2
	3	import gdb
	4	from gdb import lookup_type
	5
	6	if version_info[0] >= 3:
	7	xrange = range
	8
	9	ZERO_FIELD = "__0"
	10	FIRST_FIELD = "__1"
	11
	12
	13	def unwrap_unique_or_non_null(unique_or_nonnull):
	14	# BACKCOMPAT: rust 1.32
	15	# https://github.com/rust-lang/rust/commit/7a0911528058e87d22ea305695f4047572c5e067
	16	ptr = unique_or_nonnull["pointer"]
	17	return ptr if ptr.type.code == gdb.TYPE_CODE_PTR else ptr[ZERO_FIELD]
	18
	19
	20	class EnumProvider:
	21	def __init__(self, valobj):
	22	content = valobj[valobj.type.fields()[0]]
	23	fields = content.type.fields()
	24	self.empty = len(fields) == 0
	25	if not self.empty:
	26	if len(fields) == 1:
	27	discriminant = 0
	28	else:
	29	discriminant = int(content[fields[0]]) + 1
	30	self.active_variant = content[fields[discriminant]]
	31	self.name = fields[discriminant].name
	32	self.full_name = "{}::{}".format(valobj.type.name, self.name)
	33	else:
	34	self.full_name = valobj.type.name
	35
	36	def to_string(self):
	37	return self.full_name
	38
	39	def children(self):
	40	if not self.empty:
	41	yield self.name, self.active_variant
	42
	43
	44	class StdStringProvider:
	45	def __init__(self, valobj):
	46	self.valobj = valobj
	47	vec = valobj["vec"]
	48	self.length = int(vec["len"])
	49	self.data_ptr = unwrap_unique_or_non_null(vec["buf"]["ptr"])
	50
	51	def to_string(self):
	52	return self.data_ptr.lazy_string(encoding="utf-8", length=self.length)
	53
	54	@staticmethod
	55	def display_hint():
	56	return "string"
	57
	58
	59	class StdOsStringProvider:
	60	def __init__(self, valobj):
	61	self.valobj = valobj
	62	buf = self.valobj["inner"]["inner"]
	63	is_windows = "Wtf8Buf" in buf.type.name
	64	vec = buf[ZERO_FIELD] if is_windows else buf
65
66	self.length = int(vec["len"])
67	self.data_ptr = unwrap_unique_or_non_null(vec["buf"]["ptr"])
68
69	def to_string(self):
70	return self.data_ptr.lazy_string(encoding="utf-8", length=self.length)
71
72	def display_hint(self):
73	return "string"
74
75
76	class StdStrProvider:
77	def __init__(self, valobj):
78	self.valobj = valobj
79	self.length = int(valobj["length"])
80	self.data_ptr = valobj["data_ptr"]
81
82	def to_string(self):
83	return self.data_ptr.lazy_string(encoding="utf-8", length=self.length)
84
85	@staticmethod
86	def display_hint():
87	return "string"
88
89
90	class StdVecProvider:
91	def __init__(self, valobj):
92	self.valobj = valobj
93	self.length = int(valobj["len"])
94	self.data_ptr = unwrap_unique_or_non_null(valobj["buf"]["ptr"])
95
96	def to_string(self):
97	return "Vec(size={})".format(self.length)
98
99	def children(self):
100	saw_inaccessible = False
101	for index in xrange(self.length):
102	element_ptr = self.data_ptr + index
103	if saw_inaccessible:
104	return
105	try:
106	# rust-lang/rust#64343: passing deref expr to `str` allows
107	# catching exception on garbage pointer
108	str(element_ptr.dereference())
109	yield "[{}]".format(index), element_ptr.dereference()
110	except RuntimeError:
111	saw_inaccessible = True
112	yield str(index), "inaccessible"
113
114	@staticmethod
115	def display_hint():
116	return "array"
117
118
119	class StdVecDequeProvider:
120	def __init__(self, valobj):
121	self.valobj = valobj
122	self.head = int(valobj["head"])
123	self.tail = int(valobj["tail"])
124	self.cap = int(valobj["buf"]["cap"])
125	self.data_ptr = unwrap_unique_or_non_null(valobj["buf"]["ptr"])
126	if self.head >= self.tail:
127	self.size = self.head - self.tail
128	else:
129	self.size = self.cap + self.head - self.tail
130
131	def to_string(self):
132	return "VecDeque(size={})".format(self.size)
133
134	def children(self):
135	for index in xrange(0, self.size):
136	value = (self.data_ptr + ((self.tail + index) % self.cap)).dereference()
137	yield "[{}]".format(index), value
138
139	@staticmethod
140	def display_hint():
141	return "array"
142
143
144	class StdRcProvider:
145	def __init__(self, valobj, is_atomic=False):
146	self.valobj = valobj
147	self.is_atomic = is_atomic
148	self.ptr = unwrap_unique_or_non_null(valobj["ptr"])
149	self.value = self.ptr["data" if is_atomic else "value"]
150	self.strong = self.ptr["strong"]["v" if is_atomic else "value"]["value"]
151	self.weak = self.ptr["weak"]["v" if is_atomic else "value"]["value"] - 1
152
153	def to_string(self):
154	if self.is_atomic:
155	return "Arc(strong={}, weak={})".format(int(self.strong), int(self.weak))
156	else:
157	return "Rc(strong={}, weak={})".format(int(self.strong), int(self.weak))
158
159	def children(self):
160	yield "value", self.value
161	yield "strong", self.strong
162	yield "weak", self.weak
163
164
165	class StdCellProvider:
166	def __init__(self, valobj):
167	self.value = valobj["value"]["value"]
168
169	def to_string(self):
170	return "Cell"
171
172	def children(self):
173	yield "value", self.value
174
175
176	class StdRefProvider:
177	def __init__(self, valobj):
178	self.value = valobj["value"].dereference()
179	self.borrow = valobj["borrow"]["borrow"]["value"]["value"]
180
181	def to_string(self):
182	borrow = int(self.borrow)
183	if borrow >= 0:
184	return "Ref(borrow={})".format(borrow)
185	else:
186	return "Ref(borrow_mut={})".format(-borrow)
187
188	def children(self):
189	yield "*value", self.value
190	yield "borrow", self.borrow
191
192
193	class StdRefCellProvider:
194	def __init__(self, valobj):
195	self.value = valobj["value"]["value"]
196	self.borrow = valobj["borrow"]["value"]["value"]
197
198	def to_string(self):
199	borrow = int(self.borrow)
200	if borrow >= 0:
201	return "RefCell(borrow={})".format(borrow)
202	else:
203	return "RefCell(borrow_mut={})".format(-borrow)
204
205	def children(self):
206	yield "value", self.value
207	yield "borrow", self.borrow
208
209
210	# Yield each key (and optionally value) from a BoxedNode.
211	def children_of_node(boxed_node, height, want_values):
212	def cast_to_internal(node):
213	internal_type_name = str(node.type.target()).replace("LeafNode", "InternalNode", 1)
214	internal_type = lookup_type(internal_type_name)
215	return node.cast(internal_type.pointer())
216
217	node_ptr = unwrap_unique_or_non_null(boxed_node["ptr"])
218	node_ptr = cast_to_internal(node_ptr) if height > 0 else node_ptr
219	leaf = node_ptr["data"] if height > 0 else node_ptr.dereference()
220	keys = leaf["keys"]
221	values = leaf["vals"]
222	length = int(leaf["len"])
223
224	for i in xrange(0, length + 1):
225	if height > 0:
226	child_ptr = node_ptr["edges"][i]["value"]["value"]
227	for child in children_of_node(child_ptr, height - 1, want_values):
228	yield child
229	if i < length:
230	if want_values:
231	yield keys[i]["value"]["value"], values[i]["value"]["value"]
232	else:
233	yield keys[i]["value"]["value"]
234
235
236	class StdBTreeSetProvider:
237	def __init__(self, valobj):
238	self.valobj = valobj
239
240	def to_string(self):
241	return "BTreeSet(size={})".format(self.valobj["map"]["length"])
242
243	def children(self):
244	inner_map = self.valobj["map"]
245	if inner_map["length"] > 0:
246	root = inner_map["root"]
247	if "core::option::Option<" in root.type.name:
248	type_name = str(root.type.name).replace("core::option::Option<", "", 1)[:-1]
249	root = root.cast(gdb.lookup_type(type_name))
250
251	node_ptr = root["node"]
252	for i, child in enumerate(children_of_node(node_ptr, root["height"], False)):
253	yield "[{}]".format(i), child
254
255	@staticmethod
256	def display_hint():
257	return "array"
258
259
260	class StdBTreeMapProvider:
261	def __init__(self, valobj):
262	self.valobj = valobj
263
264	def to_string(self):
265	return "BTreeMap(size={})".format(self.valobj["length"])
266
267	def children(self):
268	if self.valobj["length"] > 0:
269	root = self.valobj["root"]
270	if "core::option::Option<" in root.type.name:
271	type_name = str(root.type.name).replace("core::option::Option<", "", 1)[:-1]
272	root = root.cast(gdb.lookup_type(type_name))
273
274	node_ptr = root["node"]
275	for i, child in enumerate(children_of_node(node_ptr, root["height"], True)):
276	yield "key{}".format(i), child[0]
277	yield "val{}".format(i), child[1]
278
279	@staticmethod
280	def display_hint():
281	return "map"
282
283
284	# BACKCOMPAT: rust 1.35
285	class StdOldHashMapProvider:
286	def __init__(self, valobj, show_values=True):
287	self.valobj = valobj
288	self.show_values = show_values
289
290	self.table = self.valobj["table"]
291	self.size = int(self.table["size"])
292	self.hashes = self.table["hashes"]
293	self.hash_uint_type = self.hashes.type
294	self.hash_uint_size = self.hashes.type.sizeof
295	self.modulo = 2 ** self.hash_uint_size
296	self.data_ptr = self.hashes[ZERO_FIELD]["pointer"]
297
298	self.capacity_mask = int(self.table["capacity_mask"])
299	self.capacity = (self.capacity_mask + 1) % self.modulo
300
301	marker = self.table["marker"].type
302	self.pair_type = marker.template_argument(0)
303	self.pair_type_size = self.pair_type.sizeof
304
305	self.valid_indices = []
306	for idx in range(self.capacity):
307	data_ptr = self.data_ptr.cast(self.hash_uint_type.pointer())
308	address = data_ptr + idx
309	hash_uint = address.dereference()
310	hash_ptr = hash_uint[ZERO_FIELD]["pointer"]
311	if int(hash_ptr) != 0:
312	self.valid_indices.append(idx)
313
314	def to_string(self):
315	if self.show_values:
316	return "HashMap(size={})".format(self.size)
317	else:
318	return "HashSet(size={})".format(self.size)
319
320	def children(self):
321	start = int(self.data_ptr) & ~1
322
323	hashes = self.hash_uint_size * self.capacity
324	align = self.pair_type_size
325	len_rounded_up = (((((hashes + align) % self.modulo - 1) % self.modulo) & ~(
326	(align - 1) % self.modulo)) % self.modulo - hashes) % self.modulo
327
328	pairs_offset = hashes + len_rounded_up
329	pairs_start = gdb.Value(start + pairs_offset).cast(self.pair_type.pointer())
330
331	for index in range(self.size):
332	table_index = self.valid_indices[index]
333	idx = table_index & self.capacity_mask
334	element = (pairs_start + idx).dereference()
335	if self.show_values:
336	yield "key{}".format(index), element[ZERO_FIELD]
337	yield "val{}".format(index), element[FIRST_FIELD]
338	else:
339	yield "[{}]".format(index), element[ZERO_FIELD]
340
341	def display_hint(self):
342	return "map" if self.show_values else "array"
343
344
345	class StdHashMapProvider:
346	def __init__(self, valobj, show_values=True):
347	self.valobj = valobj
348	self.show_values = show_values
349
350	table = self.valobj["base"]["table"]
351	capacity = int(table["bucket_mask"]) + 1
352	ctrl = table["ctrl"]["pointer"]
353
354	self.size = int(table["items"])
3dfed10e XL	355	self.pair_type = table.type.template_argument(0)
	356
	357	self.new_layout = not table.type.has_key("data")
	358	if self.new_layout:
	359	self.data_ptr = ctrl.cast(self.pair_type.pointer())
	360	else:
	361	self.data_ptr = table["data"]["pointer"]
f035d41b XL	362
	363	self.valid_indices = []
	364	for idx in range(capacity):
	365	address = ctrl + idx
	366	value = address.dereference()
	367	is_presented = value & 128 == 0
	368	if is_presented:
	369	self.valid_indices.append(idx)
	370
	371	def to_string(self):
	372	if self.show_values:
	373	return "HashMap(size={})".format(self.size)
	374	else:
	375	return "HashSet(size={})".format(self.size)
	376
	377	def children(self):
	378	pairs_start = self.data_ptr
	379
	380	for index in range(self.size):
	381	idx = self.valid_indices[index]
3dfed10e XL	382	if self.new_layout:
3dfed10e XL	383	idx = -(idx + 1)
f035d41b XL	384	element = (pairs_start + idx).dereference()
	385	if self.show_values:
	386	yield "key{}".format(index), element[ZERO_FIELD]
	387	yield "val{}".format(index), element[FIRST_FIELD]
	388	else:
	389	yield "[{}]".format(index), element[ZERO_FIELD]
	390
	391	def display_hint(self):
	392	return "map" if self.show_values else "array"