diff options
Diffstat (limited to 'scripts/qapi/schema.py')
| -rw-r--r-- | scripts/qapi/schema.py | 460 |
1 files changed, 248 insertions, 212 deletions
diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py index d759308b4e..78309a00f0 100644 --- a/scripts/qapi/schema.py +++ b/scripts/qapi/schema.py @@ -53,13 +53,13 @@ class QAPISchemaEntity: seen = {} for f in self.features: f.check_clash(self.info, seen) - if self.doc: - self.doc.connect_feature(f) - self._checked = True def connect_doc(self, doc=None): - pass + doc = doc or self.doc + if doc: + for f in self.features: + doc.connect_feature(f) def check_doc(self): if self.doc: @@ -109,29 +109,29 @@ class QAPISchemaVisitor: def visit_builtin_type(self, name, info, json_type): pass - def visit_enum_type(self, name, info, ifcond, members, prefix): + def visit_enum_type(self, name, info, ifcond, features, members, prefix): pass def visit_array_type(self, name, info, ifcond, element_type): pass - def visit_object_type(self, name, info, ifcond, base, members, variants, - features): + def visit_object_type(self, name, info, ifcond, features, + base, members, variants): pass - def visit_object_type_flat(self, name, info, ifcond, members, variants, - features): + def visit_object_type_flat(self, name, info, ifcond, features, + members, variants): pass - def visit_alternate_type(self, name, info, ifcond, variants): + def visit_alternate_type(self, name, info, ifcond, features, variants): pass - def visit_command(self, name, info, ifcond, arg_type, ret_type, gen, - success_response, boxed, allow_oob, allow_preconfig, - features): + def visit_command(self, name, info, ifcond, features, + arg_type, ret_type, gen, success_response, boxed, + allow_oob, allow_preconfig): pass - def visit_event(self, name, info, ifcond, arg_type, boxed): + def visit_event(self, name, info, ifcond, features, arg_type, boxed): pass @@ -193,6 +193,12 @@ class QAPISchemaType(QAPISchemaEntity): return None return self.name + def check(self, schema): + QAPISchemaEntity.check(self, schema) + if 'deprecated' in [f.name for f in self.features]: + raise QAPISemError( + self.info, "feature 'deprecated' is not supported for types") + def describe(self): assert self.meta return "%s type '%s'" % (self.meta, self.name) @@ -234,8 +240,8 @@ class QAPISchemaBuiltinType(QAPISchemaType): class QAPISchemaEnumType(QAPISchemaType): meta = 'enum' - def __init__(self, name, info, doc, ifcond, members, prefix): - super().__init__(name, info, doc, ifcond) + def __init__(self, name, info, doc, ifcond, features, members, prefix): + super().__init__(name, info, doc, ifcond, features) for m in members: assert isinstance(m, QAPISchemaEnumMember) m.set_defined_in(name) @@ -250,10 +256,10 @@ class QAPISchemaEnumType(QAPISchemaType): m.check_clash(self.info, seen) def connect_doc(self, doc=None): + super().connect_doc(doc) doc = doc or self.doc - if doc: - for m in self.members: - doc.connect_member(m) + for m in self.members: + m.connect_doc(doc) def is_implicit(self): # See QAPISchema._make_implicit_enum_type() and ._def_predefineds() @@ -270,15 +276,16 @@ class QAPISchemaEnumType(QAPISchemaType): def visit(self, visitor): super().visit(visitor) - visitor.visit_enum_type(self.name, self.info, self.ifcond, - self.members, self.prefix) + visitor.visit_enum_type( + self.name, self.info, self.ifcond, self.features, + self.members, self.prefix) class QAPISchemaArrayType(QAPISchemaType): meta = 'array' def __init__(self, name, info, element_type): - super().__init__(name, info, None, None) + super().__init__(name, info, None) assert isinstance(element_type, str) self._element_type_name = element_type self.element_type = None @@ -324,8 +331,8 @@ class QAPISchemaArrayType(QAPISchemaType): class QAPISchemaObjectType(QAPISchemaType): - def __init__(self, name, info, doc, ifcond, - base, local_members, variants, features): + def __init__(self, name, info, doc, ifcond, features, + base, local_members, variants): # struct has local_members, optional base, and no variants # flat union has base, variants, and no local_members # simple union has local_members, variants, and no base @@ -336,7 +343,7 @@ class QAPISchemaObjectType(QAPISchemaType): assert isinstance(m, QAPISchemaObjectTypeMember) m.set_defined_in(name) if variants is not None: - assert isinstance(variants, QAPISchemaObjectTypeVariants) + assert isinstance(variants, QAPISchemaVariants) variants.set_defined_in(name) self._base_name = base self.base = None @@ -392,12 +399,12 @@ class QAPISchemaObjectType(QAPISchemaType): m.check_clash(info, seen) def connect_doc(self, doc=None): + super().connect_doc(doc) doc = doc or self.doc - if doc: - if self.base and self.base.is_implicit(): - self.base.connect_doc(doc) - for m in self.local_members: - doc.connect_member(m) + if self.base and self.base.is_implicit(): + self.base.connect_doc(doc) + for m in self.local_members: + m.connect_doc(doc) @property def ifcond(self): @@ -433,93 +440,82 @@ class QAPISchemaObjectType(QAPISchemaType): def visit(self, visitor): super().visit(visitor) - visitor.visit_object_type(self.name, self.info, self.ifcond, - self.base, self.local_members, self.variants, - self.features) - visitor.visit_object_type_flat(self.name, self.info, self.ifcond, - self.members, self.variants, - self.features) - - -class QAPISchemaMember: - """ Represents object members, enum members and features """ - role = 'member' - - def __init__(self, name, info, ifcond=None): - assert isinstance(name, str) - self.name = name - self.info = info - self.ifcond = ifcond or [] - self.defined_in = None - - def set_defined_in(self, name): - assert not self.defined_in - self.defined_in = name - - def check_clash(self, info, seen): - cname = c_name(self.name) - if cname in seen: - raise QAPISemError( - info, - "%s collides with %s" - % (self.describe(info), seen[cname].describe(info))) - seen[cname] = self + visitor.visit_object_type( + self.name, self.info, self.ifcond, self.features, + self.base, self.local_members, self.variants) + visitor.visit_object_type_flat( + self.name, self.info, self.ifcond, self.features, + self.members, self.variants) - def describe(self, info): - role = self.role - defined_in = self.defined_in - assert defined_in - - if defined_in.startswith('q_obj_'): - # See QAPISchema._make_implicit_object_type() - reverse the - # mapping there to create a nice human-readable description - defined_in = defined_in[6:] - if defined_in.endswith('-arg'): - # Implicit type created for a command's dict 'data' - assert role == 'member' - role = 'parameter' - elif defined_in.endswith('-base'): - # Implicit type created for a flat union's dict 'base' - role = 'base ' + role - else: - # Implicit type created for a simple union's branch - assert defined_in.endswith('-wrapper') - # Unreachable and not implemented - assert False - elif defined_in.endswith('Kind'): - # See QAPISchema._make_implicit_enum_type() - # Implicit enum created for simple union's branches - assert role == 'value' - role = 'branch' - elif defined_in != info.defn_name: - return "%s '%s' of type '%s'" % (role, self.name, defined_in) - return "%s '%s'" % (role, self.name) +class QAPISchemaAlternateType(QAPISchemaType): + meta = 'alternate' -class QAPISchemaEnumMember(QAPISchemaMember): - role = 'value' + def __init__(self, name, info, doc, ifcond, features, variants): + super().__init__(name, info, doc, ifcond, features) + assert isinstance(variants, QAPISchemaVariants) + assert variants.tag_member + variants.set_defined_in(name) + variants.tag_member.set_defined_in(self.name) + self.variants = variants + def check(self, schema): + super().check(schema) + self.variants.tag_member.check(schema) + # Not calling self.variants.check_clash(), because there's nothing + # to clash with + self.variants.check(schema, {}) + # Alternate branch names have no relation to the tag enum values; + # so we have to check for potential name collisions ourselves. + seen = {} + types_seen = {} + for v in self.variants.variants: + v.check_clash(self.info, seen) + qtype = v.type.alternate_qtype() + if not qtype: + raise QAPISemError( + self.info, + "%s cannot use %s" + % (v.describe(self.info), v.type.describe())) + conflicting = set([qtype]) + if qtype == 'QTYPE_QSTRING': + if isinstance(v.type, QAPISchemaEnumType): + for m in v.type.members: + if m.name in ['on', 'off']: + conflicting.add('QTYPE_QBOOL') + if re.match(r'[-+0-9.]', m.name): + # lazy, could be tightened + conflicting.add('QTYPE_QNUM') + else: + conflicting.add('QTYPE_QNUM') + conflicting.add('QTYPE_QBOOL') + for qt in conflicting: + if qt in types_seen: + raise QAPISemError( + self.info, + "%s can't be distinguished from '%s'" + % (v.describe(self.info), types_seen[qt])) + types_seen[qt] = v.name -class QAPISchemaFeature(QAPISchemaMember): - role = 'feature' + def connect_doc(self, doc=None): + super().connect_doc(doc) + doc = doc or self.doc + for v in self.variants.variants: + v.connect_doc(doc) + def c_type(self): + return c_name(self.name) + pointer_suffix -class QAPISchemaObjectTypeMember(QAPISchemaMember): - def __init__(self, name, info, typ, optional, ifcond=None): - super().__init__(name, info, ifcond) - assert isinstance(typ, str) - assert isinstance(optional, bool) - self._type_name = typ - self.type = None - self.optional = optional + def json_type(self): + return 'value' - def check(self, schema): - assert self.defined_in - self.type = schema.resolve_type(self._type_name, self.info, - self.describe) + def visit(self, visitor): + super().visit(visitor) + visitor.visit_alternate_type( + self.name, self.info, self.ifcond, self.features, self.variants) -class QAPISchemaObjectTypeVariants: +class QAPISchemaVariants: def __init__(self, tag_name, info, tag_member, variants): # Flat unions pass tag_name but not tag_member. # Simple unions and alternates pass tag_member but not tag_name. @@ -529,7 +525,7 @@ class QAPISchemaObjectTypeVariants: assert (isinstance(tag_name, str) or isinstance(tag_member, QAPISchemaObjectTypeMember)) for v in variants: - assert isinstance(v, QAPISchemaObjectTypeVariant) + assert isinstance(v, QAPISchemaVariant) self._tag_name = tag_name self.info = info self.tag_member = tag_member @@ -579,8 +575,8 @@ class QAPISchemaObjectTypeVariants: cases = {v.name for v in self.variants} for m in self.tag_member.type.members: if m.name not in cases: - v = QAPISchemaObjectTypeVariant(m.name, self.info, - 'q_empty', m.ifcond) + v = QAPISchemaVariant(m.name, self.info, + 'q_empty', m.ifcond) v.set_defined_in(self.tag_member.defined_in) self.variants.append(v) if not self.variants: @@ -610,86 +606,114 @@ class QAPISchemaObjectTypeVariants: v.type.check_clash(info, dict(seen)) -class QAPISchemaObjectTypeVariant(QAPISchemaObjectTypeMember): - role = 'branch' +class QAPISchemaMember: + """ Represents object members, enum members and features """ + role = 'member' - def __init__(self, name, info, typ, ifcond=None): - super().__init__(name, info, typ, False, ifcond) + def __init__(self, name, info, ifcond=None): + assert isinstance(name, str) + self.name = name + self.info = info + self.ifcond = ifcond or [] + self.defined_in = None + def set_defined_in(self, name): + assert not self.defined_in + self.defined_in = name -class QAPISchemaAlternateType(QAPISchemaType): - meta = 'alternate' + def check_clash(self, info, seen): + cname = c_name(self.name) + if cname in seen: + raise QAPISemError( + info, + "%s collides with %s" + % (self.describe(info), seen[cname].describe(info))) + seen[cname] = self + + def connect_doc(self, doc): + if doc: + doc.connect_member(self) + + def describe(self, info): + role = self.role + defined_in = self.defined_in + assert defined_in + + if defined_in.startswith('q_obj_'): + # See QAPISchema._make_implicit_object_type() - reverse the + # mapping there to create a nice human-readable description + defined_in = defined_in[6:] + if defined_in.endswith('-arg'): + # Implicit type created for a command's dict 'data' + assert role == 'member' + role = 'parameter' + elif defined_in.endswith('-base'): + # Implicit type created for a flat union's dict 'base' + role = 'base ' + role + else: + # Implicit type created for a simple union's branch + assert defined_in.endswith('-wrapper') + # Unreachable and not implemented + assert False + elif defined_in.endswith('Kind'): + # See QAPISchema._make_implicit_enum_type() + # Implicit enum created for simple union's branches + assert role == 'value' + role = 'branch' + elif defined_in != info.defn_name: + return "%s '%s' of type '%s'" % (role, self.name, defined_in) + return "%s '%s'" % (role, self.name) + + +class QAPISchemaEnumMember(QAPISchemaMember): + role = 'value' + + +class QAPISchemaFeature(QAPISchemaMember): + role = 'feature' - def __init__(self, name, info, doc, ifcond, variants): - super().__init__(name, info, doc, ifcond) - assert isinstance(variants, QAPISchemaObjectTypeVariants) - assert variants.tag_member - variants.set_defined_in(name) - variants.tag_member.set_defined_in(self.name) - self.variants = variants + +class QAPISchemaObjectTypeMember(QAPISchemaMember): + def __init__(self, name, info, typ, optional, ifcond=None, features=None): + super().__init__(name, info, ifcond) + assert isinstance(typ, str) + assert isinstance(optional, bool) + for f in features or []: + assert isinstance(f, QAPISchemaFeature) + f.set_defined_in(name) + self._type_name = typ + self.type = None + self.optional = optional + self.features = features or [] def check(self, schema): - super().check(schema) - self.variants.tag_member.check(schema) - # Not calling self.variants.check_clash(), because there's nothing - # to clash with - self.variants.check(schema, {}) - # Alternate branch names have no relation to the tag enum values; - # so we have to check for potential name collisions ourselves. + assert self.defined_in + self.type = schema.resolve_type(self._type_name, self.info, + self.describe) seen = {} - types_seen = {} - for v in self.variants.variants: - v.check_clash(self.info, seen) - qtype = v.type.alternate_qtype() - if not qtype: - raise QAPISemError( - self.info, - "%s cannot use %s" - % (v.describe(self.info), v.type.describe())) - conflicting = set([qtype]) - if qtype == 'QTYPE_QSTRING': - if isinstance(v.type, QAPISchemaEnumType): - for m in v.type.members: - if m.name in ['on', 'off']: - conflicting.add('QTYPE_QBOOL') - if re.match(r'[-+0-9.]', m.name): - # lazy, could be tightened - conflicting.add('QTYPE_QNUM') - else: - conflicting.add('QTYPE_QNUM') - conflicting.add('QTYPE_QBOOL') - for qt in conflicting: - if qt in types_seen: - raise QAPISemError( - self.info, - "%s can't be distinguished from '%s'" - % (v.describe(self.info), types_seen[qt])) - types_seen[qt] = v.name + for f in self.features: + f.check_clash(self.info, seen) - def connect_doc(self, doc=None): - doc = doc or self.doc + def connect_doc(self, doc): + super().connect_doc(doc) if doc: - for v in self.variants.variants: - doc.connect_member(v) + for f in self.features: + doc.connect_feature(f) - def c_type(self): - return c_name(self.name) + pointer_suffix - def json_type(self): - return 'value' +class QAPISchemaVariant(QAPISchemaObjectTypeMember): + role = 'branch' - def visit(self, visitor): - super().visit(visitor) - visitor.visit_alternate_type(self.name, self.info, self.ifcond, - self.variants) + def __init__(self, name, info, typ, ifcond=None): + super().__init__(name, info, typ, False, ifcond) class QAPISchemaCommand(QAPISchemaEntity): meta = 'command' - def __init__(self, name, info, doc, ifcond, arg_type, ret_type, - gen, success_response, boxed, allow_oob, allow_preconfig, - features): + def __init__(self, name, info, doc, ifcond, features, + arg_type, ret_type, + gen, success_response, boxed, allow_oob, allow_preconfig): super().__init__(name, info, doc, ifcond, features) assert not arg_type or isinstance(arg_type, str) assert not ret_type or isinstance(ret_type, str) @@ -733,6 +757,7 @@ class QAPISchemaCommand(QAPISchemaEntity): % self.ret_type.describe()) def connect_doc(self, doc=None): + super().connect_doc(doc) doc = doc or self.doc if doc: if self.arg_type and self.arg_type.is_implicit(): @@ -740,19 +765,17 @@ class QAPISchemaCommand(QAPISchemaEntity): def visit(self, visitor): super().visit(visitor) - visitor.visit_command(self.name, self.info, self.ifcond, - self.arg_type, self.ret_type, - self.gen, self.success_response, - self.boxed, self.allow_oob, - self.allow_preconfig, - self.features) + visitor.visit_command( + self.name, self.info, self.ifcond, self.features, + self.arg_type, self.ret_type, self.gen, self.success_response, + self.boxed, self.allow_oob, self.allow_preconfig) class QAPISchemaEvent(QAPISchemaEntity): meta = 'event' - def __init__(self, name, info, doc, ifcond, arg_type, boxed): - super().__init__(name, info, doc, ifcond) + def __init__(self, name, info, doc, ifcond, features, arg_type, boxed): + super().__init__(name, info, doc, ifcond, features) assert not arg_type or isinstance(arg_type, str) self._arg_type_name = arg_type self.arg_type = None @@ -775,6 +798,7 @@ class QAPISchemaEvent(QAPISchemaEntity): % self.arg_type.describe()) def connect_doc(self, doc=None): + super().connect_doc(doc) doc = doc or self.doc if doc: if self.arg_type and self.arg_type.is_implicit(): @@ -782,8 +806,9 @@ class QAPISchemaEvent(QAPISchemaEntity): def visit(self, visitor): super().visit(visitor) - visitor.visit_event(self.name, self.info, self.ifcond, - self.arg_type, self.boxed) + visitor.visit_event( + self.name, self.info, self.ifcond, self.features, + self.arg_type, self.boxed) class QAPISchema: @@ -888,7 +913,7 @@ class QAPISchema: ('null', 'null', 'QNull' + pointer_suffix)]: self._def_builtin_type(*t) self.the_empty_object_type = QAPISchemaObjectType( - 'q_empty', None, None, None, None, [], None, []) + 'q_empty', None, None, None, None, None, [], None) self._def_entity(self.the_empty_object_type) qtypes = ['none', 'qnull', 'qnum', 'qstring', 'qdict', 'qlist', @@ -896,10 +921,12 @@ class QAPISchema: qtype_values = self._make_enum_members( [{'name': n} for n in qtypes], None) - self._def_entity(QAPISchemaEnumType('QType', None, None, None, + self._def_entity(QAPISchemaEnumType('QType', None, None, None, None, qtype_values, 'QTYPE')) def _make_features(self, features, info): + if features is None: + return [] return [QAPISchemaFeature(f['name'], info, f.get('if')) for f in features] @@ -911,7 +938,8 @@ class QAPISchema: # See also QAPISchemaObjectTypeMember.describe() name = name + 'Kind' # reserved by check_defn_name_str() self._def_entity(QAPISchemaEnumType( - name, info, None, ifcond, self._make_enum_members(values, info), + name, info, None, ifcond, None, + self._make_enum_members(values, info), None)) return name @@ -939,8 +967,8 @@ class QAPISchema: # TODO kill simple unions or implement the disjunction assert (ifcond or []) == typ._ifcond # pylint: disable=protected-access else: - self._def_entity(QAPISchemaObjectType(name, info, None, ifcond, - None, members, None, [])) + self._def_entity(QAPISchemaObjectType( + name, info, None, ifcond, None, None, members, None)) return name def _def_enum_type(self, expr, info, doc): @@ -948,11 +976,12 @@ class QAPISchema: data = expr['data'] prefix = expr.get('prefix') ifcond = expr.get('if') + features = self._make_features(expr.get('features'), info) self._def_entity(QAPISchemaEnumType( - name, info, doc, ifcond, + name, info, doc, ifcond, features, self._make_enum_members(data, info), prefix)) - def _make_member(self, name, typ, ifcond, info): + def _make_member(self, name, typ, ifcond, features, info): optional = False if name.startswith('*'): name = name[1:] @@ -960,10 +989,12 @@ class QAPISchema: if isinstance(typ, list): assert len(typ) == 1 typ = self._make_array_type(typ[0], info) - return QAPISchemaObjectTypeMember(name, info, typ, optional, ifcond) + return QAPISchemaObjectTypeMember(name, info, typ, optional, ifcond, + self._make_features(features, info)) def _make_members(self, data, info): - return [self._make_member(key, value['type'], value.get('if'), info) + return [self._make_member(key, value['type'], value.get('if'), + value.get('features'), info) for (key, value) in data.items()] def _def_struct_type(self, expr, info, doc): @@ -971,15 +1002,14 @@ class QAPISchema: base = expr.get('base') data = expr['data'] ifcond = expr.get('if') - features = expr.get('features', []) + features = self._make_features(expr.get('features'), info) self._def_entity(QAPISchemaObjectType( - name, info, doc, ifcond, base, + name, info, doc, ifcond, features, base, self._make_members(data, info), - None, - self._make_features(features, info))) + None)) def _make_variant(self, case, typ, ifcond, info): - return QAPISchemaObjectTypeVariant(case, info, typ, ifcond) + return QAPISchemaVariant(case, info, typ, ifcond) def _make_simple_variant(self, case, typ, ifcond, info): if isinstance(typ, list): @@ -987,14 +1017,15 @@ class QAPISchema: typ = self._make_array_type(typ[0], info) typ = self._make_implicit_object_type( typ, info, self.lookup_type(typ), - 'wrapper', [self._make_member('data', typ, None, info)]) - return QAPISchemaObjectTypeVariant(case, info, typ, ifcond) + 'wrapper', [self._make_member('data', typ, None, None, info)]) + return QAPISchemaVariant(case, info, typ, ifcond) def _def_union_type(self, expr, info, doc): name = expr['union'] data = expr['data'] base = expr.get('base') ifcond = expr.get('if') + features = self._make_features(expr.get('features'), info) tag_name = expr.get('discriminator') tag_member = None if isinstance(base, dict): @@ -1015,22 +1046,23 @@ class QAPISchema: tag_member = QAPISchemaObjectTypeMember('type', info, typ, False) members = [tag_member] self._def_entity( - QAPISchemaObjectType(name, info, doc, ifcond, base, members, - QAPISchemaObjectTypeVariants( - tag_name, info, tag_member, variants), - [])) + QAPISchemaObjectType(name, info, doc, ifcond, features, + base, members, + QAPISchemaVariants( + tag_name, info, tag_member, variants))) def _def_alternate_type(self, expr, info, doc): name = expr['alternate'] data = expr['data'] ifcond = expr.get('if') + features = self._make_features(expr.get('features'), info) variants = [self._make_variant(key, value['type'], value.get('if'), info) for (key, value) in data.items()] tag_member = QAPISchemaObjectTypeMember('type', info, 'QType', False) self._def_entity( - QAPISchemaAlternateType(name, info, doc, ifcond, - QAPISchemaObjectTypeVariants( + QAPISchemaAlternateType(name, info, doc, ifcond, features, + QAPISchemaVariants( None, info, tag_member, variants))) def _def_command(self, expr, info, doc): @@ -1043,27 +1075,31 @@ class QAPISchema: allow_oob = expr.get('allow-oob', False) allow_preconfig = expr.get('allow-preconfig', False) ifcond = expr.get('if') - features = expr.get('features', []) + features = self._make_features(expr.get('features'), info) if isinstance(data, OrderedDict): data = self._make_implicit_object_type( - name, info, ifcond, 'arg', self._make_members(data, info)) + name, info, ifcond, + 'arg', self._make_members(data, info)) if isinstance(rets, list): assert len(rets) == 1 rets = self._make_array_type(rets[0], info) - self._def_entity(QAPISchemaCommand(name, info, doc, ifcond, data, rets, + self._def_entity(QAPISchemaCommand(name, info, doc, ifcond, features, + data, rets, gen, success_response, - boxed, allow_oob, allow_preconfig, - self._make_features(features, info))) + boxed, allow_oob, allow_preconfig)) def _def_event(self, expr, info, doc): name = expr['event'] data = expr.get('data') boxed = expr.get('boxed', False) ifcond = expr.get('if') + features = self._make_features(expr.get('features'), info) if isinstance(data, OrderedDict): data = self._make_implicit_object_type( - name, info, ifcond, 'arg', self._make_members(data, info)) - self._def_entity(QAPISchemaEvent(name, info, doc, ifcond, data, boxed)) + name, info, ifcond, + 'arg', self._make_members(data, info)) + self._def_entity(QAPISchemaEvent(name, info, doc, ifcond, features, + data, boxed)) def _def_exprs(self, exprs): for expr_elem in exprs: |