1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
|
from dataclasses import MISSING
from .sexp import *
SEXP_END = type('SEXP_END', (), {})
class AtomChoice:
def __init__(self, *choices):
self.choices = choices
def __contains__(self, value):
return value in self.choices
def __atoms__(self):
return self.choices
def __map__(self, obj, parent=None):
obj, = obj
if obj not in self:
raise TypeError(f'Invalid atom {obj} for {type(self)}, valid choices are: {", ".join(map(str, self.choices))}')
return obj
def __sexp__(self, value):
yield value
class Flag:
def __init__(self, atom=None, invert=None):
self.atom, self.invert = atom, invert
def __bind_field__(self, field):
if self.atom is None:
self.atom = Atom(field.name)
if self.invert is None:
self.invert = bool(field.default)
def __atoms__(self):
return [self.atom]
def __map__(self, obj, parent=None):
return not self.invert
def __sexp__(self, value):
if bool(value) == (not self.invert):
yield self.atom
def sexp(t, v):
if v is None:
return []
elif t in (int, float, str, Atom):
return [t(v)]
elif hasattr(t, '__sexp__'):
return list(t.__sexp__(v))
elif isinstance(t, list):
t, = t
return [sexp(t, elem) for elem in v]
else:
raise TypeError(f'Python type {t} has no defined s-expression serialization')
def map_sexp(t, v, parent=None):
if t is not Atom and hasattr(t, '__map__'):
return t.__map__(v, parent=parent)
elif t in (int, float, str, Atom):
v, = v
if not isinstance(v, t):
types = set({type(v), t})
if types == {int, float} or types == {str, Atom}:
v = t(v)
else:
raise TypeError(f'Cannot map s-expression value {v} of type {type(v)} to Python type {t}')
return v
elif isinstance(t, list):
t, = t
return [map_sexp(t, elem, parent=parent) for elem in v]
else:
raise TypeError(f'Python type {t} has no defined s-expression deserialization')
class WrapperType:
def __init__(self, next_type):
self.next_type = next_type
def __bind_field__(self, field):
self.field = field
getattr(self.next_type, '__bind_field__', lambda x: None)(field)
def __atoms__(self):
if hasattr(self, 'name_atom'):
return [self.name_atom]
elif self.next_type is Atom:
return []
else:
return getattr(self.next_type, '__atoms__', lambda: [])()
class Named(WrapperType):
def __init__(self, next_type, name=None):
super().__init__(next_type)
self.name_atom = Atom(name) if name else None
def __bind_field__(self, field):
if self.next_type is not Atom:
getattr(self.next_type, '__bind_field__', lambda x: None)(field)
if self.name_atom is None:
self.name_atom = Atom(field.name)
def __map__(self, obj, parent=None):
k, *obj = obj
if self.next_type in (int, float, str, Atom) or isinstance(self.next_type, AtomChoice):
return map_sexp(self.next_type, [*obj], parent=parent)
else:
return map_sexp(self.next_type, obj, parent=parent)
def __sexp__(self, value):
value = sexp(self.next_type, value)
if value is not None:
yield [self.name_atom, *value]
class Rename(WrapperType):
def __init__(self, next_type, name=None):
super().__init__(next_type)
self.name_atom = Atom(name) if name else None
def __bind_field__(self, field):
if self.name_atom is None:
self.name_atom = Atom(field.name)
def __map__(self, obj, parent=None):
return map_sexp(self.next_type, obj, parent=parent)
def __sexp__(self, value):
value, = sexp(self.next_type, value)
if self.next_type in (str, float, int, Atom):
yield [self.name_atom, *value]
else:
key, *rest = value
yield [self.name_atom, *rest]
class OmitDefault(WrapperType):
def __bind_field__(self, field):
getattr(self.next_type, '__bind_field__', lambda x: None)(field)
if field.default_factory != MISSING:
self.default = field.default_factory()
else:
self.default = field.default
def __map__(self, obj, parent=None):
return map_sexp(self.next_type, obj, parent=parent)
def __sexp__(self, value):
if value != self.default:
yield from sexp(self.next_type, value)
class YesNoAtom:
def __init__(self, yes=Atom.yes, no=Atom.no):
self.yes, self.no = yes, no
def __map__(self, value, parent=None):
value, = value
return value == self.yes
def __sexp__(self, value):
yield self.yes if value else self.no
class Wrap(WrapperType):
def __map__(self, value, parent=None):
value, = value
return map_sexp(self.next_type, value, parent=parent)
def __sexp__(self, value):
for inner in sexp(self.next_type, value):
yield [inner]
class Array(WrapperType):
def __map__(self, value, parent=None):
return [map_sexp(self.next_type, [elem], parent=parent) for elem in value]
def __sexp__(self, value):
for e in value:
yield from sexp(self.next_type, e)
class List(WrapperType):
def __bind_field__(self, field):
self.attr = field.name
def __map__(self, value, parent):
l = getattr(parent, self.attr, [])
mapped = map_sexp(self.next_type, value, parent=parent)
l.append(mapped)
setattr(parent, self.attr, l)
def __sexp__(self, value):
for elem in value:
yield from sexp(self.next_type, elem)
class _SexpTemplate:
@staticmethod
def __atoms__(kls):
return [kls.name_atom]
@staticmethod
def __map__(kls, value, *args, parent=None, **kwargs):
positional = iter(kls.positional)
inst = kls(*args, **kwargs)
for v in value[1:]: # skip key
if isinstance(v, Atom) and v in kls.keys:
name, etype = kls.keys[v]
mapped = map_sexp(etype, [v], parent=inst)
if mapped is not None:
setattr(inst, name, mapped)
elif isinstance(v, list):
name, etype = kls.keys[v[0]]
mapped = map_sexp(etype, v, parent=inst)
if mapped is not None:
setattr(inst, name, mapped)
else:
try:
pos_key = next(positional)
setattr(inst, pos_key.name, v)
except StopIteration:
raise TypeError(f'Unhandled positional argument {v!r} while parsing {kls}')
getattr(inst, '__after_parse__', lambda x: None)(parent)
return inst
@staticmethod
def __sexp__(kls, value):
getattr(value, '__before_sexp__', lambda: None)()
out = [kls.name_atom]
for f in fields(kls):
if f.type is SEXP_END:
break
out += sexp(f.type, getattr(value, f.name))
yield out
@staticmethod
def parse(kls, data, *args, **kwargs):
return kls.__map__(parse_sexp(data), *args, **kwargs)
@staticmethod
def sexp(self):
return next(self.__sexp__(self))
def sexp_type(name=None):
def register(cls):
cls = dataclass(cls)
cls.name_atom = Atom(name) if name is not None else None
for key in '__sexp__', '__map__', '__atoms__', 'parse':
if not hasattr(cls, key):
setattr(cls, key, classmethod(getattr(_SexpTemplate, key)))
if not hasattr(cls, 'sexp'):
setattr(cls, 'sexp', getattr(_SexpTemplate, 'sexp'))
cls.positional = []
cls.keys = {}
for f in fields(cls):
f_type = f.type
if f_type is SEXP_END:
break
if hasattr(f_type, '__bind_field__'):
f_type.__bind_field__(f)
atoms = getattr(f_type, '__atoms__', lambda: [])
atoms = list(atoms())
for atom in atoms:
cls.keys[atom] = (f.name, f_type)
if not atoms:
cls.positional.append(f)
return cls
return register
|
