| 1 | """Module symbol-table generator"""
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| 2 | from __future__ import print_function
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| 3 |
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| 4 | from . import ast
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| 5 | from .consts import SC_LOCAL, SC_GLOBAL_IMPLICIT, SC_GLOBAL_EXPLICIT, \
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| 6 | SC_FREE, SC_CELL, SC_UNKNOWN
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| 7 | from .misc import mangle
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| 8 | import types
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| 9 |
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| 10 |
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| 11 | import sys
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| 12 |
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| 13 | MANGLE_LEN = 256
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| 14 |
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| 15 | class Scope:
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| 16 | # XXX how much information do I need about each name?
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| 17 | def __init__(self, name, module, klass=None):
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| 18 | self.name = name
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| 19 | self.module = module
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| 20 | self.defs = {}
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| 21 | self.uses = {}
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| 22 | self.globals = {}
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| 23 | self.params = {}
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| 24 | self.frees = {}
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| 25 | self.cells = {}
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| 26 | self.children = []
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| 27 | # nested is true if the class could contain free variables,
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| 28 | # i.e. if it is nested within another function.
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| 29 | self.nested = None
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| 30 | self.generator = None
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| 31 | self.klass = None
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| 32 | if klass is not None:
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| 33 | for i in range(len(klass)):
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| 34 | if klass[i] != '_':
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| 35 | self.klass = klass[i:]
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| 36 | break
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| 37 |
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| 38 | def __repr__(self):
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| 39 | return "<%s: %s>" % (self.__class__.__name__, self.name)
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| 40 |
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| 41 | def mangle(self, name):
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| 42 | if self.klass is None:
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| 43 | return name
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| 44 | return mangle(name, self.klass)
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| 45 |
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| 46 | def add_def(self, name):
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| 47 | self.defs[self.mangle(name)] = 1
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| 48 |
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| 49 | def add_use(self, name):
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| 50 | self.uses[self.mangle(name)] = 1
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| 51 |
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| 52 | def add_global(self, name):
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| 53 | name = self.mangle(name)
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| 54 | if name in self.uses or name in self.defs:
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| 55 | pass # XXX warn about global following def/use
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| 56 | if name in self.params:
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| 57 | raise SyntaxError, "%s in %s is global and parameter" % \
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| 58 | (name, self.name)
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| 59 | self.globals[name] = 1
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| 60 | self.module.add_def(name)
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| 61 |
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| 62 | def add_param(self, name):
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| 63 | name = self.mangle(name)
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| 64 | self.defs[name] = 1
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| 65 | self.params[name] = 1
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| 66 |
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| 67 | def get_names(self):
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| 68 | d = {}
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| 69 | d.update(self.defs)
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| 70 | d.update(self.uses)
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| 71 | d.update(self.globals)
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| 72 | return d.keys()
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| 73 |
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| 74 | def add_child(self, child):
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| 75 | self.children.append(child)
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| 76 |
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| 77 | def get_children(self):
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| 78 | return self.children
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| 79 |
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| 80 | def DEBUG(self):
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| 81 | print(self.name, self.nested and "nested" or "", file=sys.stderr)
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| 82 | print("\tglobals: ", self.globals, file=sys.stderr)
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| 83 | print("\tcells: ", self.cells, file=sys.stderr)
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| 84 | print("\tdefs: ", self.defs, file=sys.stderr)
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| 85 | print("\tuses: ", self.uses, file=sys.stderr)
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| 86 | print("\tfrees:", self.frees, file=sys.stderr)
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| 87 |
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| 88 | def check_name(self, name):
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| 89 | """Return scope of name.
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| 90 |
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| 91 | The scope of a name could be LOCAL, GLOBAL, FREE, or CELL.
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| 92 | """
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| 93 | if name in self.globals:
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| 94 | return SC_GLOBAL_EXPLICIT
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| 95 | if name in self.cells:
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| 96 | return SC_CELL
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| 97 | if name in self.defs:
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| 98 | return SC_LOCAL
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| 99 | if self.nested and (name in self.frees or name in self.uses):
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| 100 | return SC_FREE
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| 101 | if self.nested:
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| 102 | return SC_UNKNOWN
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| 103 | else:
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| 104 | return SC_GLOBAL_IMPLICIT
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| 105 |
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| 106 | def get_free_vars(self):
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| 107 | if not self.nested:
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| 108 | return ()
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| 109 | free = {}
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| 110 | free.update(self.frees)
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| 111 | for name in self.uses.keys():
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| 112 | if name not in self.defs and name not in self.globals:
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| 113 | free[name] = 1
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| 114 | return free.keys()
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| 115 |
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| 116 | def handle_children(self):
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| 117 | for child in self.children:
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| 118 | frees = child.get_free_vars()
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| 119 | globals = self.add_frees(frees)
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| 120 | for name in globals:
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| 121 | child.force_global(name)
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| 122 |
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| 123 | def force_global(self, name):
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| 124 | """Force name to be global in scope.
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| 125 |
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| 126 | Some child of the current node had a free reference to name.
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| 127 | When the child was processed, it was labelled a free
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| 128 | variable. Now that all its enclosing scope have been
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| 129 | processed, the name is known to be a global or builtin. So
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| 130 | walk back down the child chain and set the name to be global
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| 131 | rather than free.
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| 132 |
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| 133 | Be careful to stop if a child does not think the name is
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| 134 | free.
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| 135 | """
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| 136 | self.globals[name] = 1
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| 137 | if name in self.frees:
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| 138 | del self.frees[name]
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| 139 | for child in self.children:
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| 140 | if child.check_name(name) == SC_FREE:
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| 141 | child.force_global(name)
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| 142 |
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| 143 | def add_frees(self, names):
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| 144 | """Process list of free vars from nested scope.
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| 145 |
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| 146 | Returns a list of names that are either 1) declared global in the
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| 147 | parent or 2) undefined in a top-level parent. In either case,
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| 148 | the nested scope should treat them as globals.
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| 149 | """
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| 150 | child_globals = []
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| 151 | for name in names:
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| 152 | sc = self.check_name(name)
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| 153 | if self.nested:
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| 154 | if sc == SC_UNKNOWN or sc == SC_FREE \
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| 155 | or isinstance(self, ClassScope):
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| 156 | self.frees[name] = 1
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| 157 | elif sc == SC_GLOBAL_IMPLICIT:
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| 158 | child_globals.append(name)
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| 159 | elif isinstance(self, FunctionScope) and sc == SC_LOCAL:
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| 160 | self.cells[name] = 1
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| 161 | elif sc != SC_CELL:
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| 162 | child_globals.append(name)
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| 163 | else:
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| 164 | if sc == SC_LOCAL:
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| 165 | self.cells[name] = 1
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| 166 | elif sc != SC_CELL:
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| 167 | child_globals.append(name)
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| 168 | return child_globals
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| 169 |
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| 170 | def get_cell_vars(self):
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| 171 | return self.cells.keys()
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| 172 |
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| 173 | class ModuleScope(Scope):
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| 174 | __super_init = Scope.__init__
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| 175 |
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| 176 | def __init__(self):
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| 177 | self.__super_init("global", self)
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| 178 |
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| 179 | class FunctionScope(Scope):
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| 180 | pass
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| 181 |
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| 182 | class GenExprScope(Scope):
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| 183 | __super_init = Scope.__init__
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| 184 |
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| 185 | __counter = 1
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| 186 |
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| 187 | def __init__(self, module, klass=None):
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| 188 | i = self.__counter
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| 189 | self.__counter += 1
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| 190 | self.__super_init("generator expression<%d>"%i, module, klass)
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| 191 | self.add_param('.0')
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| 192 |
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| 193 | def get_names(self):
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| 194 | keys = Scope.get_names(self)
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| 195 | return keys
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| 196 |
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| 197 | class LambdaScope(FunctionScope):
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| 198 | __super_init = Scope.__init__
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| 199 |
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| 200 | __counter = 1
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| 201 |
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| 202 | def __init__(self, module, klass=None):
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| 203 | i = self.__counter
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| 204 | self.__counter += 1
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| 205 | self.__super_init("lambda.%d" % i, module, klass)
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| 206 |
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| 207 | class ClassScope(Scope):
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| 208 | __super_init = Scope.__init__
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| 209 |
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| 210 | def __init__(self, name, module):
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| 211 | self.__super_init(name, module, name)
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| 212 |
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| 213 | class SymbolVisitor:
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| 214 | def __init__(self):
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| 215 | self.scopes = {}
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| 216 | self.klass = None
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| 217 |
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| 218 | # node that define new scopes
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| 219 |
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| 220 | def visitModule(self, node):
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| 221 | scope = self.module = self.scopes[node] = ModuleScope()
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| 222 | self.visit(node.node, scope)
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| 223 |
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| 224 | visitExpression = visitModule
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| 225 |
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| 226 | def visitFunction(self, node, parent):
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| 227 | if node.decorators:
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| 228 | self.visit(node.decorators, parent)
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| 229 | parent.add_def(node.name)
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| 230 | for n in node.defaults:
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| 231 | self.visit(n, parent)
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| 232 | scope = FunctionScope(node.name, self.module, self.klass)
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| 233 | if parent.nested or isinstance(parent, FunctionScope):
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| 234 | scope.nested = 1
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| 235 | self.scopes[node] = scope
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| 236 | self._do_args(scope, node.argnames)
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| 237 | self.visit(node.code, scope)
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| 238 | self.handle_free_vars(scope, parent)
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| 239 |
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| 240 | def visitGenExpr(self, node, parent):
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| 241 | scope = GenExprScope(self.module, self.klass);
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| 242 | if parent.nested or isinstance(parent, FunctionScope) \
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| 243 | or isinstance(parent, GenExprScope):
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| 244 | scope.nested = 1
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| 245 |
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| 246 | self.scopes[node] = scope
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| 247 | self.visit(node.code, scope)
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| 248 |
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| 249 | self.handle_free_vars(scope, parent)
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| 250 |
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| 251 | def visitGenExprInner(self, node, scope):
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| 252 | for genfor in node.quals:
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| 253 | self.visit(genfor, scope)
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| 254 |
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| 255 | self.visit(node.expr, scope)
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| 256 |
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| 257 | def visitGenExprFor(self, node, scope):
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| 258 | self.visit(node.assign, scope, 1)
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| 259 | self.visit(node.iter, scope)
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| 260 | for if_ in node.ifs:
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| 261 | self.visit(if_, scope)
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| 262 |
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| 263 | def visitGenExprIf(self, node, scope):
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| 264 | self.visit(node.test, scope)
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| 265 |
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| 266 | def visitLambda(self, node, parent, assign=0):
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| 267 | # Lambda is an expression, so it could appear in an expression
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| 268 | # context where assign is passed. The transformer should catch
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| 269 | # any code that has a lambda on the left-hand side.
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| 270 | assert not assign
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| 271 |
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| 272 | for n in node.defaults:
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| 273 | self.visit(n, parent)
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| 274 | scope = LambdaScope(self.module, self.klass)
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| 275 | if parent.nested or isinstance(parent, FunctionScope):
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| 276 | scope.nested = 1
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| 277 | self.scopes[node] = scope
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| 278 | self._do_args(scope, node.argnames)
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| 279 | self.visit(node.code, scope)
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| 280 | self.handle_free_vars(scope, parent)
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| 281 |
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| 282 | def _do_args(self, scope, args):
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| 283 | for name in args:
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| 284 | if type(name) == types.TupleType:
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| 285 | self._do_args(scope, name)
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| 286 | else:
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| 287 | scope.add_param(name)
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| 288 |
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| 289 | def handle_free_vars(self, scope, parent):
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| 290 | parent.add_child(scope)
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| 291 | scope.handle_children()
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| 292 |
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| 293 | def visitClass(self, node, parent):
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| 294 | parent.add_def(node.name)
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| 295 | for n in node.bases:
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| 296 | self.visit(n, parent)
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| 297 | scope = ClassScope(node.name, self.module)
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| 298 | if parent.nested or isinstance(parent, FunctionScope):
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| 299 | scope.nested = 1
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| 300 | if node.doc is not None:
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| 301 | scope.add_def('__doc__')
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| 302 | scope.add_def('__module__')
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| 303 | self.scopes[node] = scope
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| 304 | prev = self.klass
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| 305 | self.klass = node.name
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| 306 | self.visit(node.code, scope)
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| 307 | self.klass = prev
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| 308 | self.handle_free_vars(scope, parent)
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| 309 |
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| 310 | # name can be a def or a use
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| 311 |
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| 312 | # XXX a few calls and nodes expect a third "assign" arg that is
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| 313 | # true if the name is being used as an assignment. only
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| 314 | # expressions contained within statements may have the assign arg.
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| 315 |
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| 316 | def visitName(self, node, scope, assign=0):
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| 317 | if assign:
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| 318 | scope.add_def(node.name)
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| 319 | else:
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| 320 | scope.add_use(node.name)
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| 321 |
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| 322 | # operations that bind new names
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| 323 |
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| 324 | def visitFor(self, node, scope):
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| 325 | self.visit(node.assign, scope, 1)
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| 326 | self.visit(node.list, scope)
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| 327 | self.visit(node.body, scope)
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| 328 | if node.else_:
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| 329 | self.visit(node.else_, scope)
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| 330 |
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| 331 | def visitFrom(self, node, scope):
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| 332 | for name, asname in node.names:
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| 333 | if name == "*":
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| 334 | continue
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| 335 | scope.add_def(asname or name)
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| 336 |
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| 337 | def visitImport(self, node, scope):
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| 338 | for name, asname in node.names:
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| 339 | i = name.find(".")
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| 340 | if i > -1:
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| 341 | name = name[:i]
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| 342 | scope.add_def(asname or name)
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| 343 |
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| 344 | def visitGlobal(self, node, scope):
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| 345 | for name in node.names:
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| 346 | scope.add_global(name)
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| 347 |
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| 348 | def visitAssign(self, node, scope):
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| 349 | """Propagate assignment flag down to child nodes.
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| 350 |
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| 351 | The Assign node doesn't itself contains the variables being
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| 352 | assigned to. Instead, the children in node.nodes are visited
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| 353 | with the assign flag set to true. When the names occur in
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| 354 | those nodes, they are marked as defs.
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| 355 |
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| 356 | Some names that occur in an assignment target are not bound by
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| 357 | the assignment, e.g. a name occurring inside a slice. The
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| 358 | visitor handles these nodes specially; they do not propagate
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| 359 | the assign flag to their children.
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| 360 | """
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| 361 | for n in node.nodes:
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| 362 | self.visit(n, scope, 1)
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| 363 | self.visit(node.expr, scope)
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| 364 |
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| 365 | def visitAssName(self, node, scope, assign=1):
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| 366 | scope.add_def(node.name)
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| 367 |
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| 368 | def visitAssAttr(self, node, scope, assign=0):
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| 369 | self.visit(node.expr, scope, 0)
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| 370 |
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| 371 | def visitSubscript(self, node, scope, assign=0):
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| 372 | self.visit(node.expr, scope, 0)
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| 373 | for n in node.subs:
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| 374 | self.visit(n, scope, 0)
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| 375 |
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| 376 | def visitSlice(self, node, scope, assign=0):
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| 377 | self.visit(node.expr, scope, 0)
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| 378 | if node.lower:
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| 379 | self.visit(node.lower, scope, 0)
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| 380 | if node.upper:
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| 381 | self.visit(node.upper, scope, 0)
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| 382 |
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| 383 | def visitAugAssign(self, node, scope):
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| 384 | # If the LHS is a name, then this counts as assignment.
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| 385 | # Otherwise, it's just use.
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| 386 | self.visit(node.node, scope)
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| 387 | if isinstance(node.node, ast.Name):
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| 388 | self.visit(node.node, scope, 1) # XXX worry about this
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| 389 | self.visit(node.expr, scope)
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| 390 |
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| 391 | # prune if statements if tests are false
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| 392 |
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| 393 | _const_types = types.StringType, types.IntType, types.FloatType
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| 394 |
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| 395 | def visitIf(self, node, scope):
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| 396 | for test, body in node.tests:
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| 397 | if isinstance(test, ast.Const):
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| 398 | if type(test.value) in self._const_types:
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| 399 | if not test.value:
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| 400 | continue
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| 401 | self.visit(test, scope)
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| 402 | self.visit(body, scope)
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| 403 | if node.else_:
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| 404 | self.visit(node.else_, scope)
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| 405 |
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| 406 | # a yield statement signals a generator
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| 407 |
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| 408 | def visitYield(self, node, scope):
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| 409 | scope.generator = 1
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| 410 | self.visit(node.value, scope)
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