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1"""Adjust some old Python 2 idioms to their modern counterparts.2 3* Change some type comparisons to isinstance() calls:4    type(x) == T -> isinstance(x, T)5    type(x) is T -> isinstance(x, T)6    type(x) != T -> not isinstance(x, T)7    type(x) is not T -> not isinstance(x, T)8 9* Change "while 1:" into "while True:".10 11* Change both12 13    v = list(EXPR)14    v.sort()15    foo(v)16 17and the more general18 19    v = EXPR20    v.sort()21    foo(v)22 23into24 25    v = sorted(EXPR)26    foo(v)27"""28# Author: Jacques Frechet, Collin Winter29 30# Local imports31from .. import fixer_base32from ..fixer_util import Call, Comma, Name, Node, BlankLine, syms33 34CMP = "(n='!=' | '==' | 'is' | n=comp_op< 'is' 'not' >)"35TYPE = "power< 'type' trailer< '(' x=any ')' > >"36 37class FixIdioms(fixer_base.BaseFix):38    explicit = True # The user must ask for this fixer39 40    PATTERN = r"""41        isinstance=comparison< %s %s T=any >42        |43        isinstance=comparison< T=any %s %s >44        |45        while_stmt< 'while' while='1' ':' any+ >46        |47        sorted=any<48            any*49            simple_stmt<50              expr_stmt< id1=any '='51                         power< list='list' trailer< '(' (not arglist<any+>) any ')' > >52              >53              '\n'54            >55            sort=56            simple_stmt<57              power< id2=any58                     trailer< '.' 'sort' > trailer< '(' ')' >59              >60              '\n'61            >62            next=any*63        >64        |65        sorted=any<66            any*67            simple_stmt< expr_stmt< id1=any '=' expr=any > '\n' >68            sort=69            simple_stmt<70              power< id2=any71                     trailer< '.' 'sort' > trailer< '(' ')' >72              >73              '\n'74            >75            next=any*76        >77    """ % (TYPE, CMP, CMP, TYPE)78 79    def match(self, node):80        r = super(FixIdioms, self).match(node)81        # If we've matched one of the sort/sorted subpatterns above, we82        # want to reject matches where the initial assignment and the83        # subsequent .sort() call involve different identifiers.84        if r and "sorted" in r:85            if r["id1"] == r["id2"]:86                return r87            return None88        return r89 90    def transform(self, node, results):91        if "isinstance" in results:92            return self.transform_isinstance(node, results)93        elif "while" in results:94            return self.transform_while(node, results)95        elif "sorted" in results:96            return self.transform_sort(node, results)97        else:98            raise RuntimeError("Invalid match")99 100    def transform_isinstance(self, node, results):101        x = results["x"].clone() # The thing inside of type()102        T = results["T"].clone() # The type being compared against103        x.prefix = ""104        T.prefix = " "105        test = Call(Name("isinstance"), [x, Comma(), T])106        if "n" in results:107            test.prefix = " "108            test = Node(syms.not_test, [Name("not"), test])109        test.prefix = node.prefix110        return test111 112    def transform_while(self, node, results):113        one = results["while"]114        one.replace(Name("True", prefix=one.prefix))115 116    def transform_sort(self, node, results):117        sort_stmt = results["sort"]118        next_stmt = results["next"]119        list_call = results.get("list")120        simple_expr = results.get("expr")121 122        if list_call:123            list_call.replace(Name("sorted", prefix=list_call.prefix))124        elif simple_expr:125            new = simple_expr.clone()126            new.prefix = ""127            simple_expr.replace(Call(Name("sorted"), [new],128                                     prefix=simple_expr.prefix))129        else:130            raise RuntimeError("should not have reached here")131        sort_stmt.remove()132 133        btwn = sort_stmt.prefix134        # Keep any prefix lines between the sort_stmt and the list_call and135        # shove them right after the sorted() call.136        if "\n" in btwn:137            if next_stmt:138                # The new prefix should be everything from the sort_stmt's139                # prefix up to the last newline, then the old prefix after a new140                # line.141                prefix_lines = (btwn.rpartition("\n")[0], next_stmt[0].prefix)142                next_stmt[0].prefix = "\n".join(prefix_lines)143            else:144                assert list_call.parent145                assert list_call.next_sibling is None146                # Put a blank line after list_call and set its prefix.147                end_line = BlankLine()148                list_call.parent.append_child(end_line)149                assert list_call.next_sibling is end_line150                # The new prefix should be everything up to the first new line151                # of sort_stmt's prefix.152                end_line.prefix = btwn.rpartition("\n")[0]153