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EDIT :: fix_idioms.py

"""Adjust some old Python 2 idioms to their modern counterparts. * Change some type comparisons to isinstance() calls: type(x) == T -> isinstance(x, T) type(x) is T -> isinstance(x, T) type(x) != T -> not isinstance(x, T) type(x) is not T -> not isinstance(x, T) * Change "while 1:" into "while True:". * Change both v = list(EXPR) v.sort() foo(v) and the more general v = EXPR v.sort() foo(v) into v = sorted(EXPR) foo(v) """ # Author: Jacques Frechet, Collin Winter # Local imports from .. import fixer_base from ..fixer_util import Call, Comma, Name, Node, BlankLine, syms CMP = "(n='!=' | '==' | 'is' | n=comp_op< 'is' 'not' >)" TYPE = "power< 'type' trailer< '(' x=any ')' > >" class FixIdioms(fixer_base.BaseFix): explicit = True # The user must ask for this fixer PATTERN = r""" isinstance=comparison< %s %s T=any > | isinstance=comparison< T=any %s %s > | while_stmt< 'while' while='1' ':' any+ > | sorted=any< any* simple_stmt< expr_stmt< id1=any '=' power< list='list' trailer< '(' (not arglist<any+>) any ')' > > > '\n' > sort= simple_stmt< power< id2=any trailer< '.' 'sort' > trailer< '(' ')' > > '\n' > next=any* > | sorted=any< any* simple_stmt< expr_stmt< id1=any '=' expr=any > '\n' > sort= simple_stmt< power< id2=any trailer< '.' 'sort' > trailer< '(' ')' > > '\n' > next=any* > """ % (TYPE, CMP, CMP, TYPE) def match(self, node): r = super(FixIdioms, self).match(node) # If we've matched one of the sort/sorted subpatterns above, we # want to reject matches where the initial assignment and the # subsequent .sort() call involve different identifiers. if r and "sorted" in r: if r["id1"] == r["id2"]: return r return None return r def transform(self, node, results): if "isinstance" in results: return self.transform_isinstance(node, results) elif "while" in results: return self.transform_while(node, results) elif "sorted" in results: return self.transform_sort(node, results) else: raise RuntimeError("Invalid match") def transform_isinstance(self, node, results): x = results["x"].clone() # The thing inside of type() T = results["T"].clone() # The type being compared against x.prefix = "" T.prefix = " " test = Call(Name("isinstance"), [x, Comma(), T]) if "n" in results: test.prefix = " " test = Node(syms.not_test, [Name("not"), test]) test.prefix = node.prefix return test def transform_while(self, node, results): one = results["while"] one.replace(Name("True", prefix=one.prefix)) def transform_sort(self, node, results): sort_stmt = results["sort"] next_stmt = results["next"] list_call = results.get("list") simple_expr = results.get("expr") if list_call: list_call.replace(Name("sorted", prefix=list_call.prefix)) elif simple_expr: new = simple_expr.clone() new.prefix = "" simple_expr.replace(Call(Name("sorted"), [new], prefix=simple_expr.prefix)) else: raise RuntimeError("should not have reached here") sort_stmt.remove() btwn = sort_stmt.prefix # Keep any prefix lines between the sort_stmt and the list_call and # shove them right after the sorted() call. if "\n" in btwn: if next_stmt: # The new prefix should be everything from the sort_stmt's # prefix up to the last newline, then the old prefix after a new # line. prefix_lines = (btwn.rpartition("\n")[0], next_stmt[0].prefix) next_stmt[0].prefix = "\n".join(prefix_lines) else: assert list_call.parent assert list_call.next_sibling is None # Put a blank line after list_call and set its prefix. end_line = BlankLine() list_call.parent.append_child(end_line) assert list_call.next_sibling is end_line # The new prefix should be everything up to the first new line # of sort_stmt's prefix. end_line.prefix = btwn.rpartition("\n")[0]

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