def __init__(self):
Visitor.__init__(self)
self.indenter = Indenter()
self.line = ''
self.lines = []
self.future_imports = []
class Renderer(Visitor):
"""Render an AST as nodal text
This class just renders text snippets
This class is based on the Unparser class, from
http://hg.python.org/cpython/file/3f7d5c235d82/Tools/parser/unparse.py
That file is license under the PSF License
which is available in this directory as "PYTHONLICENSE.txt"
"""
def __init__(self):
Visitor.__init__(self)
self.indenter = Indenter()
self.line = ''
self.lines = []
self.future_imports = []
def dispatch(self, node):
if isinstance(node, list):
_ = [self.visit(n) for n in node]
else:
return self.visit(node)
def new_line(self, string):
self.line = self.indenter.render(string)
def write(self, string):
if not self.line:
self.new_line(string)
self.line = self.indenter.render(string)
else:
self.line = '%s%s' % (self.line, string)
def write_line(self, string=''):
self.write(string)
if not self.line.isspace():
self.lines.append(self.line)
self.line = ''
def write_multiline_string(self, quotes, string):
self.write(quotes)
for line in string.splitlines():
self.write_line(line)
self.write(quotes)
def visit_alias(self, node):
self.write(node.name)
if node.asname:
self.write(' as %s' % node.asname)
def visit_arguments(self, node):
if node.defaults:
i = len(node.defaults)
plain_args = node.args[:-i]
default_args = node.args[-i:]
defaulted_args = zip(default_args, node.defaults)
else:
plain_args = node.args
defaulted_args = []
commas = Commas(self)
for arg in plain_args:
commas.dispatch(arg)
for arg, default in defaulted_args:
commas.dispatch(arg)
self.write('=')
self.dispatch(default)
if node.vararg:
commas.write('*')
self.dispatch(node.vararg)
if node.kwarg:
commas.write('**')
self.dispatch(node.kwarg)
def visit_body(self, node):
for child in node:
self.dispatch(child)
if not isinstance(child, (ast.ClassDef, ast.FunctionDef, BlankLine)):
self.write_line()
def visit_comprehension(self, node):
self.write(' for ')
self.dispatch(node.target)
self.write(' in ')
self.dispatch(node.iter)
for if_clause in node.ifs:
self.write(' if ')
self.dispatch(if_clause)
def visit_block(self, values, line_number):
value = values[0]
if isinstance(value, Comment) and value.lineno == line_number:
string = ': %s' % value.s
values = values[1:]
else:
string = ':'
self.write_line(string)
self.indenter.indent()
self.visit_body(values)
self.indenter.dedent()
def visit_decorators(self, node):
if not node.decorator_list:
return
for decorator in node.decorator_list:
self.write('@')
self.dispatch(decorator)
self.write_line()
def visit_keyword(self, node):
self.write(node.arg)
self.write('=')
self.dispatch(node.value)
def visit_str(self, string):
self.write(string)
def visit_Assert(self, node):
self.write('assert ')
self.dispatch(node.test)
if node.msg:
self.write(', ')
self.dispatch(node.msg)
def visit_Assign(self, node):
for target in node.targets:
self.dispatch(target)
self.write(' = ')
self.dispatch(node.value)
def visit_Attribute(self, node):
self.dispatch(node.value)
# ints are objects too, so can have attributes, e.g. 1 .__add__(1) == 2
if isinstance(node.value, ast.Num) and isinstance(node.value.n, int):
self.write(' ')
self.write('.')
self.write(node.attr)
def visit_AugAssign(self, node):
self.dispatch(node.target)
self.write(' %s= ' % self.binary_operators[node.op.__class__.__name__])
self.dispatch(node.value)
boolops = {ast.And: 'and', ast.Or: 'or'}
def visit_BoolOp(self, node):
punctuation = ' %s' % self.boolops[node.op.__class__]
punctuator = Punctuator(self, punctuation)
for value in node.values:
punctuator.dispatch(value)
binary_operators = {
'Add': '+', 'Sub': '-', 'Mult': '*', 'Div': '/', 'Mod': '%',
'LShift': '<<', 'RShift': '>>', 'BitOr': '|', 'BitXor': '^',
'BitAnd': '&', 'FloorDiv': '//', 'Pow': '**'
}
def visit_BinOp(self, node):
operator_name = node.op.__class__.__name__
self.dispatch(node.left)
self.write(' %s ' % self.binary_operators[operator_name])
self.dispatch(node.right)
def visit_BlankLine(self, node):
self.write_line('')
#pass
def visit_Break(self, _node):
self.write('break')
def visit_Call(self, node):
self.dispatch(node.func)
self.write('(')
commas = Commas(self)
for arg in node.args + node.keywords:
commas.dispatch(arg)
if node.starargs:
commas.write('*')
self.dispatch(node.starargs)
if node.kwargs:
commas.write('**')
self.dispatch(node.kwargs)
self.write(')')
def visit_ClassDef(self, node):
self.visit_decorators(node)
self.write('class %s' % node.name)
if node.bases:
self.write('(')
commas = Commas(self)
for base in node.bases:
commas.dispatch(base)
self.write(')')
self.visit_block(node.body, node.lineno)
def visit_Comment(self, node):
if node.prefix:
self.dispatch(node.prefix)
self.write(' ')
self.write(node.s)
def visit_Compare(self, node):
operators = {
'Eq': '==', 'NotEq': '!=', 'Lt': '<', 'LtE': '<=',
'Gt': '>', 'GtE': '>=', 'Is': 'is', 'IsNot': 'is not',
'In': 'in', 'NotIn': 'not in'
}
self.dispatch(node.left)
for operator_node, comparator in zip(node.ops, node.comparators):
operator_name = operator_node.__class__.__name__
operator = operators[operator_name]
self.write(' %s ' % operator)
self.dispatch(comparator)
def visit_Continue(self, _node):
self.write('continue')
def visit_Delete(self, node):
self.write('del ')
commas = Commas(self)
for target in node.targets:
commas.dispatch(target)
def visit_Dict(self, node):
self.write('{')
items = zip(node.keys, node.values)
commas = Commas(self)
for key, value in items:
commas.dispatch([key, ': ', value])
self.write('}')
def visit_DictComp(self, node):
self.write('{')
self.dispatch(node.key)
self.write(':')
self.dispatch(node.value)
for generator in node.generators:
self.dispatch(generator)
self.write('}')
def visit_DocString(self, node):
if '\n' in node.s:
self.write_multiline_string('"""', node.s)
else:
self.write('"""%s"""' % node.s)
def visit_Ellipsis(self, _node):
self.write('...')
def visit_ExceptHandler(self, node):
self.write('except')
if node.type:
self.write(' ')
self.dispatch(node.type)
if node.name:
self.write(' as ')
self.dispatch(node.name)
self.visit_block(node.body, node.lineno)
def visit_Exec(self, node):
self.write('exec ')
self.dispatch(node.body)
if node.globals:
self.write(' in ')
self.dispatch(node.globals)
if node.locals:
self.write(', ')
self.dispatch(node.locals)
def visit_Expr(self, node):
self.dispatch(node.value)
def visit_ExtSlice(self, node):
commas = Commas(self)
for dimension in node.dims:
commas.dispatch(dimension)
def visit_For(self, node):
self.write('for ')
self.dispatch(node.target)
self.write(' in ')
self.dispatch(node.iter)
self.visit_block(node.body, node.lineno)
if node.orelse:
self.write('else')
self.visit_block(node.orelse, line_after(node.body))
def visit_FunctionDef(self, node):
self.visit_decorators(node)
self.write('def %s(' % node.name)
self.dispatch(node.args)
self.write(')')
self.visit_block(node.body, node.lineno)
def visit_GeneratorExp(self, node):
self.write('(')
self.dispatch(node.elt)
for generator in node.generators:
self.dispatch(generator)
self.write(')')
def visit_Global(self, node):
self.write('global ')
commas = Commas(self)
for name in node.names:
commas.dispatch(name)
def visit_If(self, node):
self.write('if ')
self.dispatch(node.test)
self.visit_block(node.body, node.lineno)
while (node.orelse and len(node.orelse) == 1 and
isinstance(node.orelse[0], ast.If)):
node = node.orelse[0]
self.write('elif ')
self.dispatch(node.test)
self.visit_block(node.body, node.test.lineno)
if node.orelse:
self.write('else')
self.visit_block(node.orelse, line_after(node.body))
def visit_IfExp(self, node):
self.dispatch(node.body)
self.write(' if ')
self.dispatch(node.test)
self.write(' else ')
self.dispatch(node.orelse)
def visit_Import(self, node):
self.write('import ')
self.dispatch(node.names[0])
for name in node.names[1:]:
self.write(', ')
self.dispatch(name)
def visit_ImportFrom(self, node):
if node.module and node.module == '__future__':
self.future_imports.extend(n.name for n in node.names)
self.write('from ')
self.write('.' * node.level)
if node.module:
self.write(node.module)
self.write(' import ')
commas = Commas(self)
for name in node.names:
commas.dispatch(name)
def visit_Index(self, node):
self.dispatch(node.value)
def visit_Lambda(self, node):
self.write('lambda')
if node.args and node.args.args:
self.write(' ')
self.dispatch(node.args)
self.write(': ')
self.dispatch(node.body)
def visit_List(self, node):
self.write('[')
commas = Commas(self)
for item in node.elts:
commas.dispatch(item)
self.write(']')
def visit_ListComp(self, node):
self.write('[')
self.dispatch(node.elt)
for generator in node.generators:
self.dispatch(generator)
self.write(']')
def visit_Module(self, node):
self.visit_body(node.body)
def visit_Name(self, node):
self.write(node.id)
def visit_Num(self, node):
string = repr(node.n)
string = string.replace("inf", infinity_string())
self.write(string)
def visit_Pass(self, _node):
self.write('pass')
def visit_Print(self, node):
self.write('print ')
commas = Commas(self)
if node.dest:
commas.write('>> ')
self.dispatch(node.dest)
for value in node.values:
commas.dispatch(value)
stay_on_line = ',' if not node.nl else ''
self.write(stay_on_line)
def visit_Raise(self, node):
self.write('raise ')
if node.type:
self.dispatch(node.type)
if node.inst:
self.write(', ')
self.dispatch(node.inst)
if node.tback:
self.write(', ')
self.dispatch(node.tback)
def visit_Repr(self, node):
self.write('`')
self.dispatch(node.value)
self.write('`')
def visit_Return(self, node):
self.write('return')
if node.value:
self.write(' ')
self.dispatch(node.value)
def visit_Set(self, node):
self.write('{')
commas = Commas(self)
for element in node.elts:
commas.dispatch(element)
self.write('}')
def visit_SetComp(self, node):
self.write('{')
self.dispatch(node.elt)
for generator in node.generators:
self.dispatch(generator)
self.write('}')
def visit_Slice(self, node):
if node.lower:
self.dispatch(node.lower)
self.write(':')
if node.upper:
self.dispatch(node.upper)
if node.step:
self.write(':')
self.dispatch(node.step)
def visit_Str(self, node):
if '\n' in node.s:
self.write_multiline_string("'''", node.s)
else:
self.write(repr(node.s))
def visit_Subscript(self, node):
self.dispatch(node.value)
self.write('[')
self.dispatch(node.slice)
self.write(']')
def visit_TryExcept(self, node):
self.write('try')
self.visit_block(node.body, node.lineno)
for handler in node.handlers:
self.dispatch(handler)
if node.orelse:
self.write('else')
self.visit_block(node.orelse, line_after(node.body))
def visit_TryFinally(self, node):
if len(node.body) == 1 and isinstance(node.body[0], ast.TryExcept):
# try-except-finally
self.dispatch(node.body)
else:
self.write('try')
self.visit_block(node.body, node.lineno)
self.write('finally')
self.visit_block(node.finalbody, line_after(node.body))
def visit_Tuple(self, node):
loading = isinstance(node.ctx, ast.Load)
if loading:
self.write('(')
if len(node.elts) == 1:
(item,) = node.elts
self.dispatch(item)
self.write(',')
else:
commas = Commas(self)
for item in node.elts:
commas.dispatch(item)
if loading:
self.write(')')
def visit_UnaryOp(self, node):
operators = {'Invert': '~', 'Not': 'not', 'UAdd': '+', 'USub': '-'}
operator_name = node.op.__class__.__name__
operator = operators[operator_name]
space = operator_name == 'Not' and ' ' or ''
self.write('%s%s' % (operator, space))
if operator_name == 'USub' and isinstance(node.operand, ast.Num):
self.write('(')
self.dispatch(node.operand)
self.write(')')
else:
self.dispatch(node.operand)
def visit_While(self, node):
self.write('while ')
self.dispatch(node.test)
self.visit_block(node.body, node.lineno)
if node.orelse:
self.write('else')
self.visit_block(node.orelse, line_after(node.body))
def visit_With(self, node):
self.write('with ')
self.dispatch(node.context_expr)
if node.optional_vars:
self.write(' as ')
self.dispatch(node.optional_vars)
self.visit_block(node.body, node.lineno)
def visit_Yield(self, node):
self.write('yield')
if node.value:
self.write(' ')
self.dispatch(node.value)