|
1 | | -"Usage: unparse.py <path to source file>" |
2 | | -import sys |
3 | | - |
4 | | -class Unparser: |
5 | | - """Methods in this class recursively traverse an AST and |
6 | | - output source code for the abstract syntax; original formatting |
7 | | - is disregarged. """ |
8 | | - |
9 | | - def __init__(self, tree, file = sys.stdout): |
10 | | - """Unparser(tree, file=sys.stdout) -> None. |
11 | | - Print the source for tree to file.""" |
12 | | - self.f = file |
13 | | - self._indent = 0 |
14 | | - self.dispatch(tree) |
15 | | - self.f.flush() |
16 | | - |
17 | | - def fill(self, text = ""): |
18 | | - "Indent a piece of text, according to the current indentation level" |
19 | | - self.f.write("\n"+" "*self._indent + text) |
20 | | - |
21 | | - def write(self, text): |
22 | | - "Append a piece of text to the current line." |
23 | | - self.f.write(text) |
24 | | - |
25 | | - def enter(self): |
26 | | - "Print ':', and increase the indentation." |
27 | | - self.write(":") |
28 | | - self._indent += 1 |
29 | | - |
30 | | - def leave(self): |
31 | | - "Decrease the indentation level." |
32 | | - self._indent -= 1 |
33 | | - |
34 | | - def dispatch(self, tree): |
35 | | - "Dispatcher function, dispatching tree type T to method _T." |
36 | | - if isinstance(tree, list): |
37 | | - for t in tree: |
38 | | - self.dispatch(t) |
39 | | - return |
40 | | - meth = getattr(self, "_"+tree.__class__.__name__) |
41 | | - meth(tree) |
42 | | - |
43 | | - |
44 | | - ############### Unparsing methods ###################### |
45 | | - # There should be one method per concrete grammar type # |
46 | | - # Constructors should be grouped by sum type. Ideally, # |
47 | | - # this would follow the order in the grammar, but # |
48 | | - # currently doesn't. # |
49 | | - ######################################################## |
50 | | - |
51 | | - def _Module(self, tree): |
52 | | - for stmt in tree.body: |
53 | | - self.dispatch(stmt) |
54 | | - |
55 | | - # stmt |
56 | | - def _Expr(self, tree): |
57 | | - self.fill() |
58 | | - self.dispatch(tree.value) |
59 | | - |
60 | | - def _Import(self, t): |
61 | | - self.fill("import ") |
62 | | - first = True |
63 | | - for a in t.names: |
64 | | - if first: |
65 | | - first = False |
66 | | - else: |
67 | | - self.write(", ") |
68 | | - self.write(a.name) |
69 | | - if a.asname: |
70 | | - self.write(" as "+a.asname) |
71 | | - |
72 | | - def _Assign(self, t): |
73 | | - self.fill() |
74 | | - for target in t.targets: |
75 | | - self.dispatch(target) |
76 | | - self.write(" = ") |
77 | | - self.dispatch(t.value) |
78 | | - |
79 | | - def _ClassDef(self, t): |
80 | | - self.write("\n") |
81 | | - self.fill("class "+t.name) |
82 | | - if t.bases: |
83 | | - self.write("(") |
84 | | - for a in t.bases: |
85 | | - self.dispatch(a) |
86 | | - self.write(", ") |
87 | | - self.write(")") |
88 | | - self.enter() |
89 | | - self.dispatch(t.body) |
90 | | - self.leave() |
91 | | - |
92 | | - def _FunctionDef(self, t): |
93 | | - self.write("\n") |
94 | | - self.fill("def "+t.name + "(") |
95 | | - self.dispatch(t.args) |
96 | | - self.enter() |
97 | | - self.dispatch(t.body) |
98 | | - self.leave() |
99 | | - |
100 | | - def _If(self, t): |
101 | | - self.fill("if ") |
102 | | - self.dispatch(t.test) |
103 | | - self.enter() |
104 | | - # XXX elif? |
105 | | - self.dispatch(t.body) |
106 | | - self.leave() |
107 | | - if t.orelse: |
108 | | - self.fill("else") |
109 | | - self.enter() |
110 | | - self.dispatch(t.orelse) |
111 | | - self.leave() |
112 | | - |
113 | | - # expr |
114 | | - def _Str(self, tree): |
115 | | - self.write(repr(tree.s)) |
116 | | - |
117 | | - def _Name(self, t): |
118 | | - self.write(t.id) |
119 | | - |
120 | | - def _List(self, t): |
121 | | - self.write("[") |
122 | | - for e in t.elts: |
123 | | - self.dispatch(e) |
124 | | - self.write(", ") |
125 | | - self.write("]") |
126 | | - |
127 | | - unop = {"Invert":"~", "Not": "not", "UAdd":"+", "USub":"-"} |
128 | | - def _UnaryOp(self, t): |
129 | | - self.write(self.unop[t.op.__class__.__name__]) |
130 | | - self.write("(") |
131 | | - self.dispatch(t.operand) |
132 | | - self.write(")") |
133 | | - |
134 | | - # others |
135 | | - def _arguments(self, t): |
136 | | - first = True |
137 | | - # XXX t.defaults |
138 | | - for a in t.args: |
139 | | - if first:first = False |
140 | | - else: self.write(", ") |
141 | | - self.dispatch(a) |
142 | | - if t.vararg: |
143 | | - if first:first = False |
144 | | - else: self.write(", ") |
145 | | - self.write("*"+t.vararg) |
146 | | - if t.kwarg: |
147 | | - if first:first = False |
148 | | - else: self.write(", ") |
149 | | - self.write("**"+self.kwarg) |
150 | | - self.write(")") |
151 | | - |
152 | | -def roundtrip(filename): |
153 | | - source = open(filename).read() |
154 | | - tree = compile(source, filename, "exec", 0x400) |
155 | | - Unparser(tree) |
156 | | - |
157 | | -if __name__=='__main__': |
158 | | - roundtrip(sys.argv[1]) |
| 1 | +"Usage: unparse.py <path to source file>" |
| 2 | +import sys |
| 3 | + |
| 4 | +class Unparser: |
| 5 | + """Methods in this class recursively traverse an AST and |
| 6 | + output source code for the abstract syntax; original formatting |
| 7 | + is disregarged. """ |
| 8 | + |
| 9 | + def __init__(self, tree, file = sys.stdout): |
| 10 | + """Unparser(tree, file=sys.stdout) -> None. |
| 11 | + Print the source for tree to file.""" |
| 12 | + self.f = file |
| 13 | + self._indent = 0 |
| 14 | + self.dispatch(tree) |
| 15 | + self.f.flush() |
| 16 | + |
| 17 | + def fill(self, text = ""): |
| 18 | + "Indent a piece of text, according to the current indentation level" |
| 19 | + self.f.write("\n"+" "*self._indent + text) |
| 20 | + |
| 21 | + def write(self, text): |
| 22 | + "Append a piece of text to the current line." |
| 23 | + self.f.write(text) |
| 24 | + |
| 25 | + def enter(self): |
| 26 | + "Print ':', and increase the indentation." |
| 27 | + self.write(":") |
| 28 | + self._indent += 1 |
| 29 | + |
| 30 | + def leave(self): |
| 31 | + "Decrease the indentation level." |
| 32 | + self._indent -= 1 |
| 33 | + |
| 34 | + def dispatch(self, tree): |
| 35 | + "Dispatcher function, dispatching tree type T to method _T." |
| 36 | + if isinstance(tree, list): |
| 37 | + for t in tree: |
| 38 | + self.dispatch(t) |
| 39 | + return |
| 40 | + meth = getattr(self, "_"+tree.__class__.__name__) |
| 41 | + meth(tree) |
| 42 | + |
| 43 | + |
| 44 | + ############### Unparsing methods ###################### |
| 45 | + # There should be one method per concrete grammar type # |
| 46 | + # Constructors should be grouped by sum type. Ideally, # |
| 47 | + # this would follow the order in the grammar, but # |
| 48 | + # currently doesn't. # |
| 49 | + ######################################################## |
| 50 | + |
| 51 | + def _Module(self, tree): |
| 52 | + for stmt in tree.body: |
| 53 | + self.dispatch(stmt) |
| 54 | + |
| 55 | + # stmt |
| 56 | + def _Expr(self, tree): |
| 57 | + self.fill() |
| 58 | + self.dispatch(tree.value) |
| 59 | + |
| 60 | + def _Import(self, t): |
| 61 | + self.fill("import ") |
| 62 | + first = True |
| 63 | + for a in t.names: |
| 64 | + if first: |
| 65 | + first = False |
| 66 | + else: |
| 67 | + self.write(", ") |
| 68 | + self.write(a.name) |
| 69 | + if a.asname: |
| 70 | + self.write(" as "+a.asname) |
| 71 | + |
| 72 | + def _Assign(self, t): |
| 73 | + self.fill() |
| 74 | + for target in t.targets: |
| 75 | + self.dispatch(target) |
| 76 | + self.write(" = ") |
| 77 | + self.dispatch(t.value) |
| 78 | + |
| 79 | + def _ClassDef(self, t): |
| 80 | + self.write("\n") |
| 81 | + self.fill("class "+t.name) |
| 82 | + if t.bases: |
| 83 | + self.write("(") |
| 84 | + for a in t.bases: |
| 85 | + self.dispatch(a) |
| 86 | + self.write(", ") |
| 87 | + self.write(")") |
| 88 | + self.enter() |
| 89 | + self.dispatch(t.body) |
| 90 | + self.leave() |
| 91 | + |
| 92 | + def _FunctionDef(self, t): |
| 93 | + self.write("\n") |
| 94 | + self.fill("def "+t.name + "(") |
| 95 | + self.dispatch(t.args) |
| 96 | + self.enter() |
| 97 | + self.dispatch(t.body) |
| 98 | + self.leave() |
| 99 | + |
| 100 | + def _If(self, t): |
| 101 | + self.fill("if ") |
| 102 | + self.dispatch(t.test) |
| 103 | + self.enter() |
| 104 | + # XXX elif? |
| 105 | + self.dispatch(t.body) |
| 106 | + self.leave() |
| 107 | + if t.orelse: |
| 108 | + self.fill("else") |
| 109 | + self.enter() |
| 110 | + self.dispatch(t.orelse) |
| 111 | + self.leave() |
| 112 | + |
| 113 | + # expr |
| 114 | + def _Str(self, tree): |
| 115 | + self.write(repr(tree.s)) |
| 116 | + |
| 117 | + def _Name(self, t): |
| 118 | + self.write(t.id) |
| 119 | + |
| 120 | + def _List(self, t): |
| 121 | + self.write("[") |
| 122 | + for e in t.elts: |
| 123 | + self.dispatch(e) |
| 124 | + self.write(", ") |
| 125 | + self.write("]") |
| 126 | + |
| 127 | + unop = {"Invert":"~", "Not": "not", "UAdd":"+", "USub":"-"} |
| 128 | + def _UnaryOp(self, t): |
| 129 | + self.write(self.unop[t.op.__class__.__name__]) |
| 130 | + self.write("(") |
| 131 | + self.dispatch(t.operand) |
| 132 | + self.write(")") |
| 133 | + |
| 134 | + # others |
| 135 | + def _arguments(self, t): |
| 136 | + first = True |
| 137 | + # XXX t.defaults |
| 138 | + for a in t.args: |
| 139 | + if first:first = False |
| 140 | + else: self.write(", ") |
| 141 | + self.dispatch(a) |
| 142 | + if t.vararg: |
| 143 | + if first:first = False |
| 144 | + else: self.write(", ") |
| 145 | + self.write("*"+t.vararg) |
| 146 | + if t.kwarg: |
| 147 | + if first:first = False |
| 148 | + else: self.write(", ") |
| 149 | + self.write("**"+self.kwarg) |
| 150 | + self.write(")") |
| 151 | + |
| 152 | +def roundtrip(filename): |
| 153 | + source = open(filename).read() |
| 154 | + tree = compile(source, filename, "exec", 0x400) |
| 155 | + Unparser(tree) |
| 156 | + |
| 157 | +if __name__=='__main__': |
| 158 | + roundtrip(sys.argv[1]) |
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