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"""
Utility functions from 2to3, 3to2 and python-modernize (and some home-grown
ones).
Licences:
2to3: PSF License v2
3to2: Apache Software License (from 3to2/setup.py)
python-modernize licence: BSD (from python-modernize/LICENSE)
"""
from lib2to3.fixer_util import (FromImport, Newline, is_import,
find_root, does_tree_import, Comma)
from lib2to3.pytree import Leaf, Node
from lib2to3.pygram import python_symbols as syms, python_grammar
from lib2to3.pygram import token
from lib2to3.fixer_util import (Node, Call, Name, syms, Comma, Number)
import re
## These functions are from 3to2 by Joe Amenta:
def Star(prefix=None):
return Leaf(token.STAR, u'*', prefix=prefix)
def DoubleStar(prefix=None):
return Leaf(token.DOUBLESTAR, u'**', prefix=prefix)
def Minus(prefix=None):
return Leaf(token.MINUS, u'-', prefix=prefix)
def commatize(leafs):
u"""
Accepts/turns: (Name, Name, ..., Name, Name)
Returns/into: (Name, Comma, Name, Comma, ..., Name, Comma, Name)
"""
new_leafs = []
for leaf in leafs:
new_leafs.append(leaf)
new_leafs.append(Comma())
del new_leafs[-1]
return new_leafs
def indentation(node):
u"""
Returns the indentation for this node
Iff a node is in a suite, then it has indentation.
"""
while node.parent is not None and node.parent.type != syms.suite:
node = node.parent
if node.parent is None:
return u""
# The first three children of a suite are NEWLINE, INDENT, (some other node)
# INDENT.value contains the indentation for this suite
# anything after (some other node) has the indentation as its prefix.
if node.type == token.INDENT:
return node.value
elif node.prev_sibling is not None and node.prev_sibling.type == token.INDENT:
return node.prev_sibling.value
elif node.prev_sibling is None:
return u""
else:
return node.prefix
def indentation_step(node):
u"""
Dirty little trick to get the difference between each indentation level
Implemented by finding the shortest indentation string
(technically, the "least" of all of the indentation strings, but
tabs and spaces mixed won't get this far, so those are synonymous.)
"""
r = find_root(node)
# Collect all indentations into one set.
all_indents = set(i.value for i in r.pre_order() if i.type == token.INDENT)
if not all_indents:
# nothing is indented anywhere, so we get to pick what we want
return u" " # four spaces is a popular convention
else:
return min(all_indents)
def suitify(parent):
u"""
Turn the stuff after the first colon in parent's children
into a suite, if it wasn't already
"""
for node in parent.children:
if node.type == syms.suite:
# already in the prefered format, do nothing
return
# One-liners have no suite node, we have to fake one up
for i, node in enumerate(parent.children):
if node.type == token.COLON:
break
else:
raise ValueError(u"No class suite and no ':'!")
# Move everything into a suite node
suite = Node(syms.suite, [Newline(), Leaf(token.INDENT, indentation(node) + indentation_step(node))])
one_node = parent.children[i+1]
one_node.remove()
one_node.prefix = u''
suite.append_child(one_node)
parent.append_child(suite)
def NameImport(package, as_name=None, prefix=None):
u"""
Accepts a package (Name node), name to import it as (string), and
optional prefix and returns a node:
import <package> [as <as_name>]
"""
if prefix is None:
prefix = u""
children = [Name(u"import", prefix=prefix), package]
if as_name is not None:
children.extend([Name(u"as", prefix=u" "),
Name(as_name, prefix=u" ")])
return Node(syms.import_name, children)
_compound_stmts = (syms.if_stmt, syms.while_stmt, syms.for_stmt, syms.try_stmt, syms.with_stmt)
_import_stmts = (syms.import_name, syms.import_from)
def import_binding_scope(node):
u"""
Generator yields all nodes for which a node (an import_stmt) has scope
The purpose of this is for a call to _find() on each of them
"""
# import_name / import_from are small_stmts
assert node.type in _import_stmts
test = node.next_sibling
# A small_stmt can only be followed by a SEMI or a NEWLINE.
while test.type == token.SEMI:
nxt = test.next_sibling
# A SEMI can only be followed by a small_stmt or a NEWLINE
if nxt.type == token.NEWLINE:
break
else:
yield nxt
# A small_stmt can only be followed by either a SEMI or a NEWLINE
test = nxt.next_sibling
# Covered all subsequent small_stmts after the import_stmt
# Now to cover all subsequent stmts after the parent simple_stmt
parent = node.parent
assert parent.type == syms.simple_stmt
test = parent.next_sibling
while test is not None:
# Yes, this will yield NEWLINE and DEDENT. Deal with it.
yield test
test = test.next_sibling
context = parent.parent
# Recursively yield nodes following imports inside of a if/while/for/try/with statement
if context.type in _compound_stmts:
# import is in a one-liner
c = context
while c.next_sibling is not None:
yield c.next_sibling
c = c.next_sibling
context = context.parent
# Can't chain one-liners on one line, so that takes care of that.
p = context.parent
if p is None:
return
# in a multi-line suite
while p.type in _compound_stmts:
if context.type == syms.suite:
yield context
context = context.next_sibling
if context is None:
context = p.parent
p = context.parent
if p is None:
break
def ImportAsName(name, as_name, prefix=None):
new_name = Name(name)
new_as = Name(u"as", prefix=u" ")
new_as_name = Name(as_name, prefix=u" ")
new_node = Node(syms.import_as_name, [new_name, new_as, new_as_name])
if prefix is not None:
new_node.prefix = prefix
return new_node
def future_import(feature, node):
"""
This seems to work
"""
root = find_root(node)
if does_tree_import(u"__future__", feature, node):
return
# Look for a shebang or encoding line
shebang_encoding_idx = None
for idx, node in enumerate(root.children):
# Is it a shebang or encoding line?
if is_shebang_comment(node) or is_encoding_comment(node):
shebang_encoding_idx = idx
if node.type == syms.simple_stmt and \
len(node.children) > 0 and node.children[0].type == token.STRING:
# skip over docstring
continue
names = check_future_import(node)
if not names:
# not a future statement; need to insert before this
break
if feature in names:
# already imported
return
import_ = FromImport(u'__future__', [Leaf(token.NAME, feature, prefix=" ")])
if shebang_encoding_idx == 0 and idx == 0:
# If this __future__ import would go on the first line,
# detach the shebang / encoding prefix from the current first line.
# and attach it to our new __future__ import node.
import_.prefix = root.children[0].prefix
root.children[0].prefix = u''
# End the __future__ import line with a newline and add a blank line
# afterwards:
children = [import_ , Newline()]
root.insert_child(idx, Node(syms.simple_stmt, children))
def future_import2(feature, node):
"""
An alternative to future_import() which might not work ...
"""
root = find_root(node)
if does_tree_import(u"__future__", feature, node):
return
insert_pos = 0
for idx, node in enumerate(root.children):
if node.type == syms.simple_stmt and node.children and \
node.children[0].type == token.STRING:
insert_pos = idx + 1
break
for thing_after in root.children[insert_pos:]:
if thing_after.type == token.NEWLINE:
insert_pos += 1
continue
prefix = thing_after.prefix
thing_after.prefix = u""
break
else:
prefix = u""
import_ = FromImport(u"__future__", [Leaf(token.NAME, feature, prefix=u" ")])
children = [import_, Newline()]
root.insert_child(insert_pos, Node(syms.simple_stmt, children, prefix=prefix))
def parse_args(arglist, scheme):
u"""
Parse a list of arguments into a dict
"""
arglist = [i for i in arglist if i.type != token.COMMA]
ret_mapping = dict([(k, None) for k in scheme])
for i, arg in enumerate(arglist):
if arg.type == syms.argument and arg.children[1].type == token.EQUAL:
# argument < NAME '=' any >
slot = arg.children[0].value
ret_mapping[slot] = arg.children[2]
else:
slot = scheme[i]
ret_mapping[slot] = arg
return ret_mapping
# def is_import_from(node):
# """Returns true if the node is a statement "from ... import ..."
# """
# return node.type == syms.import_from
def is_import_stmt(node):
return (node.type == syms.simple_stmt and node.children and
is_import(node.children[0]))
def touch_import_top(package, name_to_import, node):
"""Works like `does_tree_import` but adds an import statement at the
top if it was not imported (but below any __future__ imports).
Based on lib2to3.fixer_util.touch_import()
Calling this multiple times adds the imports in reverse order.
Also adds "standard_library.install_aliases()" after "from future import
standard_library". This should probably be factored into another function.
"""
root = find_root(node)
if does_tree_import(package, name_to_import, root):
return
# Ideally, we would look for whether futurize --all-imports has been run,
# as indicated by the presence of ``from builtins import (ascii, ...,
# zip)`` -- and, if it has, we wouldn't import the name again.
# Look for __future__ imports and insert below them
found = False
for name in ['absolute_import', 'division', 'print_function',
'unicode_literals']:
if does_tree_import('__future__', name, root):
found = True
break
if found:
# At least one __future__ import. We want to loop until we've seen them
# all.
start, end = None, None
for idx, node in enumerate(root.children):
if check_future_import(node):
start = idx
# Start looping
idx2 = start
while node:
node = node.next_sibling
idx2 += 1
if not check_future_import(node):
end = idx2
break
break
assert start is not None
assert end is not None
insert_pos = end
else:
# No __future__ imports.
# We look for a docstring and insert the new node below that. If no docstring
# exists, just insert the node at the top.
for idx, node in enumerate(root.children):
if node.type != syms.simple_stmt:
break
if not (node.children and node.children[0].type == token.STRING):
# This is the usual case.
break
insert_pos = idx
if package is None:
import_ = Node(syms.import_name, [
Leaf(token.NAME, u"import"),
Leaf(token.NAME, name_to_import, prefix=u" ")
])
else:
import_ = FromImport(package, [Leaf(token.NAME, name_to_import, prefix=u" ")])
if name_to_import == u'standard_library':
# Add:
# standard_library.install_aliases()
# after:
# from future import standard_library
install_hooks = Node(syms.simple_stmt,
[Node(syms.power,
[Leaf(token.NAME, u'standard_library'),
Node(syms.trailer, [Leaf(token.DOT, u'.'),
Leaf(token.NAME, u'install_aliases')]),
Node(syms.trailer, [Leaf(token.LPAR, u'('),
Leaf(token.RPAR, u')')])
])
]
)
children_hooks = [install_hooks, Newline()]
else:
children_hooks = []
FromImport(package, [Leaf(token.NAME, name_to_import, prefix=u" ")])
children_import = [import_, Newline()]
root.insert_child(insert_pos, Node(syms.simple_stmt, children_import))
if len(children_hooks) > 0:
root.insert_child(insert_pos + 1, Node(syms.simple_stmt, children_hooks))
## The following functions are from python-modernize by Armin Ronacher:
# (a little edited).
def check_future_import(node):
"""If this is a future import, return set of symbols that are imported,
else return None."""
# node should be the import statement here
savenode = node
if not (node.type == syms.simple_stmt and node.children):
return set()
node = node.children[0]
# now node is the import_from node
if not (node.type == syms.import_from and
# node.type == token.NAME and # seems to break it
hasattr(node.children[1], 'value') and
node.children[1].value == u'__future__'):
return set()
node = node.children[3]
# now node is the import_as_name[s]
# print(python_grammar.number2symbol[node.type]) # breaks sometimes
if node.type == syms.import_as_names:
result = set()
for n in node.children:
if n.type == token.NAME:
result.add(n.value)
elif n.type == syms.import_as_name:
n = n.children[0]
assert n.type == token.NAME
result.add(n.value)
return result
elif node.type == syms.import_as_name:
node = node.children[0]
assert node.type == token.NAME
return set([node.value])
elif node.type == token.NAME:
return set([node.value])
else:
# TODO: handle brackets like this:
# from __future__ import (absolute_import, division)
assert False, "strange import: %s" % savenode
SHEBANG_REGEX = r'^#!.*python'
ENCODING_REGEX = r"^#.*coding[:=]\s*([-\w.]+)"
def is_shebang_comment(node):
"""
Comments are prefixes for Leaf nodes. Returns whether the given node has a
prefix that looks like a shebang line or an encoding line:
#!/usr/bin/env python
#!/usr/bin/python3
"""
return bool(re.match(SHEBANG_REGEX, node.prefix))
def is_encoding_comment(node):
"""
Comments are prefixes for Leaf nodes. Returns whether the given node has a
prefix that looks like an encoding line:
# coding: utf-8
# encoding: utf-8
# -*- coding: <encoding name> -*-
# vim: set fileencoding=<encoding name> :
"""
return bool(re.match(ENCODING_REGEX, node.prefix))
def wrap_in_fn_call(fn_name, args, prefix=None):
"""
Example:
>>> wrap_in_fn_call("oldstr", (arg,))
oldstr(arg)
>>> wrap_in_fn_call("olddiv", (arg1, arg2))
olddiv(arg1, arg2)
"""
assert len(args) > 0
if len(args) == 1:
newargs = args
elif len(args) == 2:
expr1, expr2 = args
newargs = [expr1, Comma(), expr2]
else:
assert NotImplementedError('write me')
return Call(Name(fn_name), newargs, prefix=prefix)
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