1#!/usr/bin/env python
2## vim:ts=4:et:nowrap
3"""A user-defined wrapper around string objects
4
5Note: string objects have grown methods in Python 1.6
6This module requires Python 1.6 or later.
7"""
8import sys
9import collections
10
11__all__ = ["UserString","MutableString"]
12
13class UserString(collections.Sequence):
14    def __init__(self, seq):
15        if isinstance(seq, basestring):
16            self.data = seq
17        elif isinstance(seq, UserString):
18            self.data = seq.data[:]
19        else:
20            self.data = str(seq)
21    def __str__(self): return str(self.data)
22    def __repr__(self): return repr(self.data)
23    def __int__(self): return int(self.data)
24    def __long__(self): return long(self.data)
25    def __float__(self): return float(self.data)
26    def __complex__(self): return complex(self.data)
27    def __hash__(self): return hash(self.data)
28
29    def __cmp__(self, string):
30        if isinstance(string, UserString):
31            return cmp(self.data, string.data)
32        else:
33            return cmp(self.data, string)
34    def __contains__(self, char):
35        return char in self.data
36
37    def __len__(self): return len(self.data)
38    def __getitem__(self, index): return self.__class__(self.data[index])
39    def __getslice__(self, start, end):
40        start = max(start, 0); end = max(end, 0)
41        return self.__class__(self.data[start:end])
42
43    def __add__(self, other):
44        if isinstance(other, UserString):
45            return self.__class__(self.data + other.data)
46        elif isinstance(other, basestring):
47            return self.__class__(self.data + other)
48        else:
49            return self.__class__(self.data + str(other))
50    def __radd__(self, other):
51        if isinstance(other, basestring):
52            return self.__class__(other + self.data)
53        else:
54            return self.__class__(str(other) + self.data)
55    def __mul__(self, n):
56        return self.__class__(self.data*n)
57    __rmul__ = __mul__
58    def __mod__(self, args):
59        return self.__class__(self.data % args)
60
61    # the following methods are defined in alphabetical order:
62    def capitalize(self): return self.__class__(self.data.capitalize())
63    def center(self, width, *args):
64        return self.__class__(self.data.center(width, *args))
65    def count(self, sub, start=0, end=sys.maxint):
66        return self.data.count(sub, start, end)
67    def decode(self, encoding=None, errors=None): # XXX improve this?
68        if encoding:
69            if errors:
70                return self.__class__(self.data.decode(encoding, errors))
71            else:
72                return self.__class__(self.data.decode(encoding))
73        else:
74            return self.__class__(self.data.decode())
75    def encode(self, encoding=None, errors=None): # XXX improve this?
76        if encoding:
77            if errors:
78                return self.__class__(self.data.encode(encoding, errors))
79            else:
80                return self.__class__(self.data.encode(encoding))
81        else:
82            return self.__class__(self.data.encode())
83    def endswith(self, suffix, start=0, end=sys.maxint):
84        return self.data.endswith(suffix, start, end)
85    def expandtabs(self, tabsize=8):
86        return self.__class__(self.data.expandtabs(tabsize))
87    def find(self, sub, start=0, end=sys.maxint):
88        return self.data.find(sub, start, end)
89    def index(self, sub, start=0, end=sys.maxint):
90        return self.data.index(sub, start, end)
91    def isalpha(self): return self.data.isalpha()
92    def isalnum(self): return self.data.isalnum()
93    def isdecimal(self): return self.data.isdecimal()
94    def isdigit(self): return self.data.isdigit()
95    def islower(self): return self.data.islower()
96    def isnumeric(self): return self.data.isnumeric()
97    def isspace(self): return self.data.isspace()
98    def istitle(self): return self.data.istitle()
99    def isupper(self): return self.data.isupper()
100    def join(self, seq): return self.data.join(seq)
101    def ljust(self, width, *args):
102        return self.__class__(self.data.ljust(width, *args))
103    def lower(self): return self.__class__(self.data.lower())
104    def lstrip(self, chars=None): return self.__class__(self.data.lstrip(chars))
105    def partition(self, sep):
106        return self.data.partition(sep)
107    def replace(self, old, new, maxsplit=-1):
108        return self.__class__(self.data.replace(old, new, maxsplit))
109    def rfind(self, sub, start=0, end=sys.maxint):
110        return self.data.rfind(sub, start, end)
111    def rindex(self, sub, start=0, end=sys.maxint):
112        return self.data.rindex(sub, start, end)
113    def rjust(self, width, *args):
114        return self.__class__(self.data.rjust(width, *args))
115    def rpartition(self, sep):
116        return self.data.rpartition(sep)
117    def rstrip(self, chars=None): return self.__class__(self.data.rstrip(chars))
118    def split(self, sep=None, maxsplit=-1):
119        return self.data.split(sep, maxsplit)
120    def rsplit(self, sep=None, maxsplit=-1):
121        return self.data.rsplit(sep, maxsplit)
122    def splitlines(self, keepends=0): return self.data.splitlines(keepends)
123    def startswith(self, prefix, start=0, end=sys.maxint):
124        return self.data.startswith(prefix, start, end)
125    def strip(self, chars=None): return self.__class__(self.data.strip(chars))
126    def swapcase(self): return self.__class__(self.data.swapcase())
127    def title(self): return self.__class__(self.data.title())
128    def translate(self, *args):
129        return self.__class__(self.data.translate(*args))
130    def upper(self): return self.__class__(self.data.upper())
131    def zfill(self, width): return self.__class__(self.data.zfill(width))
132
133class MutableString(UserString, collections.MutableSequence):
134    """mutable string objects
135
136    Python strings are immutable objects.  This has the advantage, that
137    strings may be used as dictionary keys.  If this property isn't needed
138    and you insist on changing string values in place instead, you may cheat
139    and use MutableString.
140
141    But the purpose of this class is an educational one: to prevent
142    people from inventing their own mutable string class derived
143    from UserString and than forget thereby to remove (override) the
144    __hash__ method inherited from UserString.  This would lead to
145    errors that would be very hard to track down.
146
147    A faster and better solution is to rewrite your program using lists."""
148    def __init__(self, string=""):
149        from warnings import warnpy3k
150        warnpy3k('the class UserString.MutableString has been removed in '
151                    'Python 3.0', stacklevel=2)
152        self.data = string
153
154    # We inherit object.__hash__, so we must deny this explicitly
155    __hash__ = None
156
157    def __setitem__(self, index, sub):
158        if isinstance(index, slice):
159            if isinstance(sub, UserString):
160                sub = sub.data
161            elif not isinstance(sub, basestring):
162                sub = str(sub)
163            start, stop, step = index.indices(len(self.data))
164            if step == -1:
165                start, stop = stop+1, start+1
166                sub = sub[::-1]
167            elif step != 1:
168                # XXX(twouters): I guess we should be reimplementing
169                # the extended slice assignment/deletion algorithm here...
170                raise TypeError, "invalid step in slicing assignment"
171            start = min(start, stop)
172            self.data = self.data[:start] + sub + self.data[stop:]
173        else:
174            if index < 0:
175                index += len(self.data)
176            if index < 0 or index >= len(self.data): raise IndexError
177            self.data = self.data[:index] + sub + self.data[index+1:]
178    def __delitem__(self, index):
179        if isinstance(index, slice):
180            start, stop, step = index.indices(len(self.data))
181            if step == -1:
182                start, stop = stop+1, start+1
183            elif step != 1:
184                # XXX(twouters): see same block in __setitem__
185                raise TypeError, "invalid step in slicing deletion"
186            start = min(start, stop)
187            self.data = self.data[:start] + self.data[stop:]
188        else:
189            if index < 0:
190                index += len(self.data)
191            if index < 0 or index >= len(self.data): raise IndexError
192            self.data = self.data[:index] + self.data[index+1:]
193    def __setslice__(self, start, end, sub):
194        start = max(start, 0); end = max(end, 0)
195        if isinstance(sub, UserString):
196            self.data = self.data[:start]+sub.data+self.data[end:]
197        elif isinstance(sub, basestring):
198            self.data = self.data[:start]+sub+self.data[end:]
199        else:
200            self.data =  self.data[:start]+str(sub)+self.data[end:]
201    def __delslice__(self, start, end):
202        start = max(start, 0); end = max(end, 0)
203        self.data = self.data[:start] + self.data[end:]
204    def immutable(self):
205        return UserString(self.data)
206    def __iadd__(self, other):
207        if isinstance(other, UserString):
208            self.data += other.data
209        elif isinstance(other, basestring):
210            self.data += other
211        else:
212            self.data += str(other)
213        return self
214    def __imul__(self, n):
215        self.data *= n
216        return self
217    def insert(self, index, value):
218        self[index:index] = value
219
220if __name__ == "__main__":
221    # execute the regression test to stdout, if called as a script:
222    import os
223    called_in_dir, called_as = os.path.split(sys.argv[0])
224    called_as, py = os.path.splitext(called_as)
225    if '-q' in sys.argv:
226        from test import test_support
227        test_support.verbose = 0
228    __import__('test.test_' + called_as.lower())
229