diff options
Diffstat (limited to 'lib/python2.7/lib2to3/fixes/fix_metaclass.py')
| -rw-r--r-- | lib/python2.7/lib2to3/fixes/fix_metaclass.py | 228 |
1 files changed, 0 insertions, 228 deletions
diff --git a/lib/python2.7/lib2to3/fixes/fix_metaclass.py b/lib/python2.7/lib2to3/fixes/fix_metaclass.py deleted file mode 100644 index c86fbea..0000000 --- a/lib/python2.7/lib2to3/fixes/fix_metaclass.py +++ /dev/null @@ -1,228 +0,0 @@ -"""Fixer for __metaclass__ = X -> (metaclass=X) methods. - - The various forms of classef (inherits nothing, inherits once, inherints - many) don't parse the same in the CST so we look at ALL classes for - a __metaclass__ and if we find one normalize the inherits to all be - an arglist. - - For one-liner classes ('class X: pass') there is no indent/dedent so - we normalize those into having a suite. - - Moving the __metaclass__ into the classdef can also cause the class - body to be empty so there is some special casing for that as well. - - This fixer also tries very hard to keep original indenting and spacing - in all those corner cases. - -""" -# Author: Jack Diederich - -# Local imports -from .. import fixer_base -from ..pygram import token -from ..fixer_util import Name, syms, Node, Leaf - - -def has_metaclass(parent): - """ we have to check the cls_node without changing it. - There are two possiblities: - 1) clsdef => suite => simple_stmt => expr_stmt => Leaf('__meta') - 2) clsdef => simple_stmt => expr_stmt => Leaf('__meta') - """ - for node in parent.children: - if node.type == syms.suite: - return has_metaclass(node) - elif node.type == syms.simple_stmt and node.children: - expr_node = node.children[0] - if expr_node.type == syms.expr_stmt and expr_node.children: - left_side = expr_node.children[0] - if isinstance(left_side, Leaf) and \ - left_side.value == '__metaclass__': - return True - return False - - -def fixup_parse_tree(cls_node): - """ one-line classes don't get a suite in the parse tree so we add - one to normalize the tree - """ - for node in cls_node.children: - if node.type == syms.suite: - # already in the preferred format, do nothing - return - - # !%@#! oneliners have no suite node, we have to fake one up - for i, node in enumerate(cls_node.children): - if node.type == token.COLON: - break - else: - raise ValueError("No class suite and no ':'!") - - # move everything into a suite node - suite = Node(syms.suite, []) - while cls_node.children[i+1:]: - move_node = cls_node.children[i+1] - suite.append_child(move_node.clone()) - move_node.remove() - cls_node.append_child(suite) - node = suite - - -def fixup_simple_stmt(parent, i, stmt_node): - """ if there is a semi-colon all the parts count as part of the same - simple_stmt. We just want the __metaclass__ part so we move - everything efter the semi-colon into its own simple_stmt node - """ - for semi_ind, node in enumerate(stmt_node.children): - if node.type == token.SEMI: # *sigh* - break - else: - return - - node.remove() # kill the semicolon - new_expr = Node(syms.expr_stmt, []) - new_stmt = Node(syms.simple_stmt, [new_expr]) - while stmt_node.children[semi_ind:]: - move_node = stmt_node.children[semi_ind] - new_expr.append_child(move_node.clone()) - move_node.remove() - parent.insert_child(i, new_stmt) - new_leaf1 = new_stmt.children[0].children[0] - old_leaf1 = stmt_node.children[0].children[0] - new_leaf1.prefix = old_leaf1.prefix - - -def remove_trailing_newline(node): - if node.children and node.children[-1].type == token.NEWLINE: - node.children[-1].remove() - - -def find_metas(cls_node): - # find the suite node (Mmm, sweet nodes) - for node in cls_node.children: - if node.type == syms.suite: - break - else: - raise ValueError("No class suite!") - - # look for simple_stmt[ expr_stmt[ Leaf('__metaclass__') ] ] - for i, simple_node in list(enumerate(node.children)): - if simple_node.type == syms.simple_stmt and simple_node.children: - expr_node = simple_node.children[0] - if expr_node.type == syms.expr_stmt and expr_node.children: - # Check if the expr_node is a simple assignment. - left_node = expr_node.children[0] - if isinstance(left_node, Leaf) and \ - left_node.value == u'__metaclass__': - # We found a assignment to __metaclass__. - fixup_simple_stmt(node, i, simple_node) - remove_trailing_newline(simple_node) - yield (node, i, simple_node) - - -def fixup_indent(suite): - """ If an INDENT is followed by a thing with a prefix then nuke the prefix - Otherwise we get in trouble when removing __metaclass__ at suite start - """ - kids = suite.children[::-1] - # find the first indent - while kids: - node = kids.pop() - if node.type == token.INDENT: - break - - # find the first Leaf - while kids: - node = kids.pop() - if isinstance(node, Leaf) and node.type != token.DEDENT: - if node.prefix: - node.prefix = u'' - return - else: - kids.extend(node.children[::-1]) - - -class FixMetaclass(fixer_base.BaseFix): - BM_compatible = True - - PATTERN = """ - classdef<any*> - """ - - def transform(self, node, results): - if not has_metaclass(node): - return - - fixup_parse_tree(node) - - # find metaclasses, keep the last one - last_metaclass = None - for suite, i, stmt in find_metas(node): - last_metaclass = stmt - stmt.remove() - - text_type = node.children[0].type # always Leaf(nnn, 'class') - - # figure out what kind of classdef we have - if len(node.children) == 7: - # Node(classdef, ['class', 'name', '(', arglist, ')', ':', suite]) - # 0 1 2 3 4 5 6 - if node.children[3].type == syms.arglist: - arglist = node.children[3] - # Node(classdef, ['class', 'name', '(', 'Parent', ')', ':', suite]) - else: - parent = node.children[3].clone() - arglist = Node(syms.arglist, [parent]) - node.set_child(3, arglist) - elif len(node.children) == 6: - # Node(classdef, ['class', 'name', '(', ')', ':', suite]) - # 0 1 2 3 4 5 - arglist = Node(syms.arglist, []) - node.insert_child(3, arglist) - elif len(node.children) == 4: - # Node(classdef, ['class', 'name', ':', suite]) - # 0 1 2 3 - arglist = Node(syms.arglist, []) - node.insert_child(2, Leaf(token.RPAR, u')')) - node.insert_child(2, arglist) - node.insert_child(2, Leaf(token.LPAR, u'(')) - else: - raise ValueError("Unexpected class definition") - - # now stick the metaclass in the arglist - meta_txt = last_metaclass.children[0].children[0] - meta_txt.value = 'metaclass' - orig_meta_prefix = meta_txt.prefix - - if arglist.children: - arglist.append_child(Leaf(token.COMMA, u',')) - meta_txt.prefix = u' ' - else: - meta_txt.prefix = u'' - - # compact the expression "metaclass = Meta" -> "metaclass=Meta" - expr_stmt = last_metaclass.children[0] - assert expr_stmt.type == syms.expr_stmt - expr_stmt.children[1].prefix = u'' - expr_stmt.children[2].prefix = u'' - - arglist.append_child(last_metaclass) - - fixup_indent(suite) - - # check for empty suite - if not suite.children: - # one-liner that was just __metaclass_ - suite.remove() - pass_leaf = Leaf(text_type, u'pass') - pass_leaf.prefix = orig_meta_prefix - node.append_child(pass_leaf) - node.append_child(Leaf(token.NEWLINE, u'\n')) - - elif len(suite.children) > 1 and \ - (suite.children[-2].type == token.INDENT and - suite.children[-1].type == token.DEDENT): - # there was only one line in the class body and it was __metaclass__ - pass_leaf = Leaf(text_type, u'pass') - suite.insert_child(-1, pass_leaf) - suite.insert_child(-1, Leaf(token.NEWLINE, u'\n')) |