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
|
from rpython.tool.pairtype import (
pairtype, pair, extendabletype, pairmro, DoubleDispatchRegistry,
doubledispatch)
def test_binop():
### Binary operation example
class __extend__(pairtype(int, int)):
def add((x, y)):
return 'integer: %s+%s' % (x, y)
def sub((x, y)):
return 'integer: %s-%s' % (x, y)
class __extend__(pairtype(bool, bool)):
def add((x, y)):
return 'bool: %s+%s' % (x, y)
assert pair(3, 4).add() == 'integer: 3+4'
assert pair(3, 4).sub() == 'integer: 3-4'
assert pair(3, True).add() == 'integer: 3+True'
assert pair(3, True).sub() == 'integer: 3-True'
assert pair(False, 4).add() == 'integer: False+4'
assert pair(False, 4).sub() == 'integer: False-4'
assert pair(False, True).add() == 'bool: False+True'
assert pair(False, True).sub() == 'integer: False-True'
def test_somebuiltin():
### Operation on built-in types
class MiniPickler:
def __init__(self):
self.data = []
def emit(self, datum):
self.data.append(datum)
class __extend__(pairtype(MiniPickler, int)):
def write((pickler, x)):
pickler.emit('I%d' % x)
class __extend__(pairtype(MiniPickler, str)):
def write((pickler, x)):
pickler.emit('S%s' % x)
class __extend__(pairtype(MiniPickler, list)):
def write((pickler, x)):
for item in x:
pair(pickler, item).write()
pickler.emit('L%d' % len(x))
p = MiniPickler()
pair(p, [1, 2, ['hello', 3]]).write()
assert p.data == ['I1', 'I2', 'Shello', 'I3', 'L2', 'L3']
def test_some_multimethod():
### Another multimethod example
class Block:
def __init__(self, exit):
self.exit = exit
class Jump:
pass
class Switch:
pass
class C_Generator:
def __init__(self):
self.lines = []
class __extend__(pairtype(C_Generator, Block)):
def emit((gen, block), inputvars):
gen.lines.append("C code for block")
outputvars = inputvars + ['v4', 'v5']
pair(gen, block.exit).emit(outputvars)
class __extend__(pairtype(C_Generator, Jump)):
def emit((gen, jump), inputvars):
gen.lines.append("goto xyz")
class __extend__(pairtype(C_Generator, Switch)):
def emit((gen, jump), inputvars):
gen.lines.append("switch (%s) { ... }" % inputvars[-1])
g = C_Generator()
pair(g, Block(Switch())).emit(['v1', 'v2'])
assert g.lines == ["C code for block", "switch (v5) { ... }"]
class Lisp_Generator:
def __init__(self):
self.progn = []
class __extend__(pairtype(Lisp_Generator, Block)):
def emit((gen, block), inputvars):
gen.progn.append("(do 'something)")
g = Lisp_Generator()
pair(g, Block(Switch())).emit(['v1', 'v2'])
assert g.progn == ["(do 'something)"]
def test_multiple_extend():
class A:
__metaclass__ = extendabletype
class B:
__metaclass__ = extendabletype
class __extend__(A, B):
def f(self):
pass
assert hasattr(A, 'f')
assert hasattr(B, 'f')
def test_pairmro():
class A(object): pass
class A2(A): pass
class A3(A2): pass
class B(object): pass
class B2(B): pass
parent_pairtypes = pairtype(A3, B2).__mro__[:-2]
assert (tuple(pairtype(a, b) for a, b in pairmro(A3, B2)) == parent_pairtypes)
def test_doubledispatch_registry():
class A(object): pass
class A2(A): pass
class A3(A2): pass
class B(object): pass
class B2(B): pass
reg = DoubleDispatchRegistry()
reg[object, object] = "default"
assert reg[A3, B2] == "default"
reg[A2, B2] = "A2-B2"
assert reg[A, B2] == "default"
assert reg[A3, B2] == "A2-B2"
reg[A3, B] = "A3-B"
assert reg[A3, B2] == "A2-B2" # note that A2,B2 wins over A3,B
def test_doubledispatch_function():
@doubledispatch
def f(x, y, z):
return z
@f.register(int, int)
def f_int(x, y, z):
return 42
assert f(1., 1., 0) == 0
assert f(1, 1, 0) == 42
|
