/usr/share/pyshared/sourcecodegen/visitor.py is in python-sourcecodegen 0.6.14-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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from compiler import ast
from cStringIO import StringIO
version = sys.version_info[:3]
def triple_quote(doc):
return '"""%s"""' % doc.replace('"""', '\"\"\"')
def format_argnames(argnames):
return ", ".join(
isinstance(name, tuple) and "(%s)" % format_argnames(name) or name \
for name in argnames)
def format_ass(node):
if isinstance(node, ast.AssTuple):
return "(%s)" % ", ".join(format_ass(ass) for ass in node)
return node.name
class prioritized(object):
def __init__(self, generator, priority):
self.generator = generator
self.priority = priority
def __iter__(self):
return self.generator
def prioritize(priority):
def decorator(func):
def visit(self, node):
return prioritized(func(self, node), priority)
return visit
return decorator
def unary(symbol, priority):
@prioritize(prioritize)
def visit(self, node):
yield symbol
child = self.visit(node.expr)
if child.priority < priority:
yield '('
yield child
yield ')'
else:
yield child
return visit
def binary(symbol, priority):
@prioritize(prioritize)
def visit(self, node):
left = self.visit(node.left)
right = self.visit(node.right)
if left.priority < priority and right.priority < priority:
yield '('
yield left
yield ' %s ' % symbol
yield right
yield ')'
else:
yield left
yield ' %s ' % symbol
yield right
return visit
def n_ary(symbol, priority):
@prioritize(prioritize)
def visit(self, node):
yield '('
for condition in tuple(node)[:-1]:
yield self.visit(condition)
yield ' %s ' % symbol
yield self.visit(tuple(node)[-1])
yield ')'
return visit
class CodeStream(object):
def __init__(self, indentation_string="\t"):
self.indentation_string = indentation_string
self.indentation = 0
self.stream = StringIO()
self.clear = True
def __call__(self, value):
if value is None:
return self.write(None)
if isinstance(value, basestring):
return self.out(value)
if isinstance(value, tuple) and self.clear is False:
self.write()
self.clear = True
self.indentation += 1
self(value)
self.indentation -= 1
else:
for part in value:
self(part)
def write(self, text=None):
if text or self.clear == False:
self.out(text)
self.stream.write('\n')
self.clear = True
def out(self, text):
if self.clear is True:
indentation = self.indentation_string * self.indentation
self.stream.write(indentation)
self.clear = False
self.stream.write(text or "")
def getvalue(self):
return self.stream.getvalue()
class ASTVisitor(object):
def __init__(self, tree):
self.tree = tree
def __call__(self):
stream = CodeStream()
stream(self.visit(self.tree))
return stream.getvalue()
def visit(self, node):
name = node.__class__.__name__
try:
func = getattr(self, 'visit%s' % name)
except AttributeError:
raise NotImplementedError(
"Unable to visit `%s`." % repr(node))
gen = func(node)
if isinstance(gen, prioritized):
return gen
return prioritized(gen, 0)
def visitModule(self, node):
if node.doc is not None:
yield triple_quote(node.doc)
yield None
for node in self.visit(node.node):
yield node
def visitStmt(self, node):
yield tuple(self.visit(child) for child in node.nodes if child is not None)
def visitIf(self, node):
for index, test in enumerate(node.tests):
if index == 0:
yield "if "
else:
yield "elif "
condition, statement = test
yield self.visit(condition)
yield ":"
yield self.visit(statement),
if node.else_:
yield "else:"
yield self.visit(node.else_),
@prioritize(-3)
def visitName(self, node):
yield node.name
def visitPass(self, node):
yield "pass"
yield None
def visitDiscard(self, node):
yield self.visit(node.expr)
yield None
def visitAssign(self, node):
for index, ass in enumerate(tuple(node.nodes)):
yield self.visit(ass)
if index < len(tuple(node.nodes)) - 1:
yield " = "
yield " = "
yield self.visit(node.expr)
yield None
def visitAssName(self, node):
if node.flags == 'OP_DELETE':
yield "del "
yield node.name
if node.flags == 'OP_DELETE':
yield None
def visitFunction(self, node):
if node.decorators:
yield self.visit(node.decorators)
yield "def %s(" % node.name
argnames = list(node.argnames)
if argnames:
if node.kwargs:
kwargs = argnames.pop()
if node.varargs:
varargs = argnames.pop()
if node.defaults:
yield format_argnames(argnames[:-len(node.defaults)])
for index, default in enumerate(node.defaults):
name = argnames[index-len(node.defaults)]
if len(argnames) > len(node.defaults) or index > 0:
yield ", %s=" % name
else:
yield "%s=" % name
yield self.visit(default)
else:
yield format_argnames(argnames)
if node.varargs:
if len(node.argnames) > 1:
yield ", "
yield "*%s" % varargs
if node.kwargs:
if len(node.argnames) > 1 or node.varargs:
yield ", "
yield "**%s" % kwargs
yield "):"
if node.doc:
yield triple_quote(node.doc),
yield self.visit(node.code),
@prioritize(0)
def visitConst(self, node):
yield repr(node.value)
def visitDecorators(self, node):
for decorator in tuple(node):
yield '@'
yield self.visit(decorator)
yield None
def visitCallFunc(self, node):
yield self.visit(node.node)
yield '('
for arg in tuple(node.args)[:-1]:
yield self.visit(arg)
yield ", "
if node.args:
yield self.visit(node.args[-1])
if node.star_args:
if node.args:
yield ", *"
else:
yield "*"
yield self.visit(node.star_args)
if node.dstar_args:
if node.args:
yield ", **"
else:
yield "**"
yield self.visit(node.dstar_args)
yield ")"
def visitKeyword(self, node):
yield "%s=" % node.name
yield self.visit(node.expr)
def visitAssTuple(self, node):
first = node
while isinstance(first, ast.AssTuple):
first = first.nodes[0]
if first.flags == 'OP_DELETE':
yield "del "
yield format_ass(node)
if first.flags == 'OP_DELETE':
yield None
@prioritize(0)
def visitTuple(self, node):
yield "("
for index, item in enumerate(tuple(node)):
yield self.visit(item)
if index < len(tuple(node)) - 1:
yield ", "
if len(node.nodes) == 1:
yield ", "
yield ")"
def visitGenExpr(self, node):
yield "("
yield self.visit(node.code)
yield ")"
def visitListComp(self, node):
yield "["
yield self.visitGenExprInner(node)
yield "]"
def visitGenExprInner(self, node):
yield self.visit(node.expr)
for qual in node.quals:
yield self.visit(qual)
def visitGenExprFor(self, node):
yield " for "
yield self.visit(node.assign)
yield " in "
yield self.visit(node.iter)
for _if in node.ifs:
yield self.visit(_if)
def visitGenExprIf(self, node):
yield " if "
yield self.visit(node.test)
def visitListCompFor(self, node):
yield " for "
yield self.visit(node.assign)
yield " in "
yield self.visit(node.list)
for _if in node.ifs:
yield self.visit(_if)
def visitListCompIf(self, node):
yield " if "
yield self.visit(node.test)
def visitCompare(self, node):
yield self.visit(node.expr)
for op, expr in node.ops:
yield ' %s ' % op
yield self.visit(expr)
def visitImport(self, node):
yield "import "
for index, (name, alias) in enumerate(node.names):
yield name
if alias is not None:
yield " as %s" % alias
if index < len(node.names) - 1:
yield ", "
yield None
def visitFrom(self, node):
yield "from %s import " % node.modname
for index, (name, alias) in enumerate(node.names):
yield name
if alias is not None:
yield " as %s" % alias
if index < len(node.names) - 1:
yield ", "
yield None
def visitReturn(self, node):
yield "return "
yield self.visit(node.value)
yield None
def visitBreak(self, node):
yield "break"
yield None
def visitContinue(self, node):
yield "continue"
yield None
def visitWhile(self, node):
yield "while "
yield self.visit(node.test)
yield ":"
yield self.visit(node.body),
if node.else_ is not None:
yield "else:"
yield self.visit(node.else_),
def visitTryExcept(self, node):
yield "try:"
yield self.visit(node.body),
for cls, var, body in node.handlers:
yield "except"
if cls is not None:
yield " "
yield self.visit(cls)
if var is not None:
if cls is None:
yield " "
else:
yield ", "
yield self.visit(var)
yield ":"
yield self.visit(body),
if node.else_:
yield "else:"
yield self.visit(node.else_),
def visitTryFinally(self, node):
if version < (2,5):
yield "try:"
yield self.visit(node.body),
yield "finally:"
yield self.visit(node.final),
else:
yield self.visit(node.body)
yield "finally:"
yield self.visit(node.final),
def visitClass(self, node):
yield "class %s" % node.name
if node.bases:
yield "("
for index, base in enumerate(node.bases):
yield self.visit(base)
if index < len(node.bases) - 1:
yield ", "
yield ")"
yield ":"
if node.doc:
yield triple_quote(node.doc), self.visit(node.code)
else:
yield self.visit(node.code)
@prioritize(-2)
def visitLambda(self, node):
yield "lambda"
argnames = list(node.argnames)
if argnames:
yield " "
if node.kwargs:
kwargs = argnames.pop()
if node.varargs:
varargs = argnames.pop()
if node.defaults:
yield format_argnames(argnames[:-len(node.defaults)])
for index, default in enumerate(node.defaults):
name = argnames[index-len(node.defaults)]
yield ", %s=" % name
yield self.visit(default)
else:
yield format_argnames(argnames)
offset = (node.varargs or 0) + (node.kwargs or 0)
if node.varargs:
if len(node.argnames) > offset:
yield ", "
yield "*%s" % varargs
if node.kwargs:
if node.varargs or len(node.argnames) > offset:
yield ", "
yield "**%s" % kwargs
yield ": "
yield self.visit(node.code)
def visitGetattr(self, node):
yield self.visit(node.expr)
yield ".%s" % node.attrname
def visitAssAttr(self, node):
if node.flags == 'OP_DELETE':
yield "del "
yield self.visit(node.expr)
yield ".%s" % node.attrname
if node.flags == 'OP_DELETE':
yield None
def visitSubscript(self, node):
if node.flags == 'OP_DELETE':
yield "del "
yield self.visit(node.expr)
yield '['
for index, sub in enumerate(node.subs):
if isinstance(sub, ast.Sliceobj):
for i, slice in enumerate(tuple(sub)):
yield self.visit(slice)
if i < len(tuple(sub)) - 1:
yield ":"
else:
yield self.visit(sub)
if index < len(node.subs) - 1:
yield ', '
yield ']'
if node.flags == 'OP_DELETE':
yield None
def visitSlice(self, node):
if node.flags == 'OP_DELETE':
yield "del "
yield self.visit(node.expr)
yield '['
if node.lower:
yield self.visit(node.lower)
yield ':'
if node.upper:
yield self.visit(node.upper)
yield ']'
if node.flags == 'OP_DELETE':
yield None
def visitSliceobj(self, node):
yield 'slice('
for index, item in enumerate(tuple(node)):
yield self.visit(item)
if index < len(tuple(node)) - 1:
yield ", "
yield ')'
def visitExec(self, node):
yield "exec "
yield self.visit(node.expr)
if node.locals:
yield " in "
yield self.visit(node.locals)
if node.globals:
yield ", "
yield self.visit(node.globals)
yield None
def visitAssert(self, node):
yield "assert "
yield self.visit(node.test)
if node.fail is not None:
yield ", "
yield self.visit(node.fail)
yield None
def visitRaise(self, node):
yield "raise "
yield self.visit(node.expr1)
if node.expr2:
yield ", "
yield self.visit(node.expr2)
if node.expr3:
yield ", "
yield self.visit(node.expr3)
def visitPrintnl(self, node):
yield "print "
if node.dest is not None:
yield ">> "
yield self.visit(node.dest)
yield ", "
for index, expr in enumerate(tuple(node.nodes)):
if expr is None:
continue
yield self.visit(expr)
if index < len(tuple(node.nodes)) - 1 and node.nodes[index+1] is not None:
yield ", "
yield None
def visitIfExp(self, node):
yield self.visit(node.then)
yield " if "
yield self.visit(node.test)
yield " else "
yield self.visit(node.else_)
def visitWith(self, node):
raise NotImplementedError(
"The `with` keyword is not supported.")
def visitAugAssign(self, node):
yield self.visit(node.node)
yield " %s " % node.op
yield self.visit(node.expr)
yield None
def visitList(self, node):
yield '['
for index, item in enumerate(node.nodes):
yield self.visit(item)
if index < len(node.nodes) - 1:
yield ", "
yield ']'
def visitDict(self, node):
yield '{'
for index, (expr, value) in enumerate(node.items):
yield self.visit(expr)
yield ': '
yield self.visit(value)
if index < len(node.items) - 1:
yield ", "
yield '}'
def visitFor(self, node):
yield "for %s in " % format_ass(node.assign)
yield self.visit(node.list)
yield ":"
yield self.visit(node.body)
if node.else_ is not None:
yield "else:"
yield self.visit(node.else_)
def visitYield(self, node):
yield "yield "
yield self.visit(node.value)
yield None
visitPower = binary('**', 10)
visitInvert = unary('~', 9)
visitUnaryAdd = unary('+', 8)
visitUnarySub = unary('-', 8)
visitMul = binary('*', 7)
visitMod = binary('%', 7)
visitDiv = binary('/', 7)
visitAdd = binary('+', 6)
visitSub = binary('-', 6)
visitLeftShift = binary('<<', 5)
visitRightShift = binary('>>', 5)
visitBitand = n_ary('&', 4)
visitBitxor = n_ary('^', 3)
visitBitor = n_ary('|', 2)
visitNot = unary('not ', 1)
visitAnd = n_ary('and', 0)
visitOr = n_ary('or', -1)
|