1 """Adjust some old Python 2 idioms to their modern counterparts.
2
3 * Change some type comparisons to isinstance() calls:
4 type(x) == T -> isinstance(x, T)
5 type(x) is T -> isinstance(x, T)
6 type(x) != T -> not isinstance(x, T)
7 type(x) is not T -> not isinstance(x, T)
8
9 * Change "while 1:" into "while True:".
10
11 * Change both
12
13 v = list(EXPR)
14 v.sort()
15 foo(v)
16
17 and the more general
18
19 v = EXPR
20 v.sort()
21 foo(v)
22
23 into
24
25 v = sorted(EXPR)
26 foo(v)
27 """
28 # Author: Jacques Frechet, Collin Winter
29
30 # Local imports
31 from .. import fixer_base
32 from ..fixer_util import Call, Comma, Name, Node, BlankLine, syms
33
34 CMP = "(n='!=' | '==' | 'is' | n=comp_op< 'is' 'not' >)"
35 TYPE = "power< 'type' trailer< '(' x=any ')' > >"
36
37 class ESC[4;38;5;81mFixIdioms(ESC[4;38;5;149mfixer_baseESC[4;38;5;149m.ESC[4;38;5;149mBaseFix):
38 explicit = True # The user must ask for this fixer
39
40 PATTERN = r"""
41 isinstance=comparison< %s %s T=any >
42 |
43 isinstance=comparison< T=any %s %s >
44 |
45 while_stmt< 'while' while='1' ':' any+ >
46 |
47 sorted=any<
48 any*
49 simple_stmt<
50 expr_stmt< id1=any '='
51 power< list='list' trailer< '(' (not arglist<any+>) any ')' > >
52 >
53 '\n'
54 >
55 sort=
56 simple_stmt<
57 power< id2=any
58 trailer< '.' 'sort' > trailer< '(' ')' >
59 >
60 '\n'
61 >
62 next=any*
63 >
64 |
65 sorted=any<
66 any*
67 simple_stmt< expr_stmt< id1=any '=' expr=any > '\n' >
68 sort=
69 simple_stmt<
70 power< id2=any
71 trailer< '.' 'sort' > trailer< '(' ')' >
72 >
73 '\n'
74 >
75 next=any*
76 >
77 """ % (TYPE, CMP, CMP, TYPE)
78
79 def match(self, node):
80 r = super(FixIdioms, self).match(node)
81 # If we've matched one of the sort/sorted subpatterns above, we
82 # want to reject matches where the initial assignment and the
83 # subsequent .sort() call involve different identifiers.
84 if r and "sorted" in r:
85 if r["id1"] == r["id2"]:
86 return r
87 return None
88 return r
89
90 def transform(self, node, results):
91 if "isinstance" in results:
92 return self.transform_isinstance(node, results)
93 elif "while" in results:
94 return self.transform_while(node, results)
95 elif "sorted" in results:
96 return self.transform_sort(node, results)
97 else:
98 raise RuntimeError("Invalid match")
99
100 def transform_isinstance(self, node, results):
101 x = results["x"].clone() # The thing inside of type()
102 T = results["T"].clone() # The type being compared against
103 x.prefix = ""
104 T.prefix = " "
105 test = Call(Name("isinstance"), [x, Comma(), T])
106 if "n" in results:
107 test.prefix = " "
108 test = Node(syms.not_test, [Name("not"), test])
109 test.prefix = node.prefix
110 return test
111
112 def transform_while(self, node, results):
113 one = results["while"]
114 one.replace(Name("True", prefix=one.prefix))
115
116 def transform_sort(self, node, results):
117 sort_stmt = results["sort"]
118 next_stmt = results["next"]
119 list_call = results.get("list")
120 simple_expr = results.get("expr")
121
122 if list_call:
123 list_call.replace(Name("sorted", prefix=list_call.prefix))
124 elif simple_expr:
125 new = simple_expr.clone()
126 new.prefix = ""
127 simple_expr.replace(Call(Name("sorted"), [new],
128 prefix=simple_expr.prefix))
129 else:
130 raise RuntimeError("should not have reached here")
131 sort_stmt.remove()
132
133 btwn = sort_stmt.prefix
134 # Keep any prefix lines between the sort_stmt and the list_call and
135 # shove them right after the sorted() call.
136 if "\n" in btwn:
137 if next_stmt:
138 # The new prefix should be everything from the sort_stmt's
139 # prefix up to the last newline, then the old prefix after a new
140 # line.
141 prefix_lines = (btwn.rpartition("\n")[0], next_stmt[0].prefix)
142 next_stmt[0].prefix = "\n".join(prefix_lines)
143 else:
144 assert list_call.parent
145 assert list_call.next_sibling is None
146 # Put a blank line after list_call and set its prefix.
147 end_line = BlankLine()
148 list_call.parent.append_child(end_line)
149 assert list_call.next_sibling is end_line
150 # The new prefix should be everything up to the first new line
151 # of sort_stmt's prefix.
152 end_line.prefix = btwn.rpartition("\n")[0]