UserString class from Peter Funk <pf@artcom-gmbh.de>.

1 files changed, 158 insertions, 0 deletions

diff --git a/Lib/UserString.py b/Lib/UserString.py
new file mode 100755
index 0000000..c2c2bed
--- /dev/null
+++ b/Lib/UserString.py
@@ -0,0 +1,158 @@
+#!/usr/bin/env python
+## vim:ts=4:et:nowrap
+"""A user-defined wrapper around string objects
+
+Note: string objects have grown methods in Python 1.6 
+This module requires Python 1.6 or later.
+"""
+from types import StringType, UnicodeType
+import sys
+
+class UserString:
+    def __init__(self, seq):
+        if isinstance(seq, StringType) or isinstance(seq, UnicodeType):
+            self.data = seq
+        elif isinstance(seq, UserString):
+            self.data = seq.data[:]
+        else: 
+            self.data = str(seq)
+    def __str__(self): return str(self.data)
+    def __repr__(self): return repr(self.data)
+    def __int__(self): return int(self.data)
+    def __long__(self): return long(self.data)
+    def __float__(self): return float(self.data)
+    def __complex__(self): return complex(self.data)
+    def __hash__(self): return hash(self.data)
+
+    def __cmp__(self, string):
+        if isinstance(string, UserString):
+            return cmp(self.data, string.data)
+        else:
+            return cmp(self.data, string)
+    def __contains__(self, char):
+        return char in self.data
+
+    def __len__(self): return len(self.data)
+    def __getitem__(self, index): return self.__class__(self.data[index])
+    def __getslice__(self, start, end):
+        start = max(start, 0); end = max(end, 0)
+        return self.__class__(self.data[start:end])
+
+    def __add__(self, other):
+        if isinstance(other, UserString):
+            return self.__class__(self.data + other.data)
+        elif isinstance(other, StringType) or isinstance(other, UnicodeType):
+            return self.__class__(self.data + other)
+        else:
+            return self.__class__(self.data + str(other))
+    def __radd__(self, other):
+        if isinstance(other, StringType) or isinstance(other, UnicodeType):
+            return self.__class__(other + self.data)
+        else:
+            return self.__class__(str(other) + self.data)
+    def __mul__(self, n):
+        return self.__class__(self.data*n)
+    __rmul__ = __mul__
+
+    # the following methods are defined in alphabetical order:
+    def capitalize(self): return self.__class__(self.data.capitalize())
+    def center(self, width): return self.__class__(self.data.center(width))
+    def count(self, sub, start=0, end=sys.maxint):
+        return self.data.count(sub, start, end)
+    def encode(self, encoding=None, errors=None): # XXX improve this?
+        if encoding:
+            if errors:
+                return self.__class__(self.data.encode(encoding, errors))
+            else:
+                return self.__class__(self.data.encode(encoding))
+        else: 
+            return self.__class__(self.data.encode())
+    def endswith(self, suffix, start=0, end=sys.maxint):
+        return self.data.endswith(suffix, start, end)
+    def expandtabs(self, tabsize=8): 
+        return self.__class__(self.data.expandtabs(tabsize))
+    def find(self, sub, start=0, end=sys.maxint): 
+        return self.data.find(sub, start, end)
+    def index(self, sub, start=0, end=sys.maxint): 
+        return self.data.index(sub, start, end)
+    def isdecimal(self): return self.data.isdecimal()
+    def isdigit(self): return self.data.isdigit()
+    def islower(self): return self.data.islower()
+    def isnumeric(self): return self.data.isnumeric()
+    def isspace(self): return self.data.isspace()
+    def istitle(self): return self.data.istitle()
+    def isupper(self): return self.data.isupper()
+    def join(self, seq): return self.data.join(seq)
+    def ljust(self, width): return self.__class__(self.data.ljust(width))
+    def lower(self): return self.__class__(self.data.lower())
+    def lstrip(self): return self.__class__(self.data.lstrip())
+    def replace(self, old, new, maxsplit=-1): 
+        return self.__class__(self.data.replace(old, new, maxsplit))
+    def rfind(self, sub, start=0, end=sys.maxint): 
+        return self.data.rfind(sub, start, end)
+    def rindex(self, sub, start=0, end=sys.maxint): 
+        return self.data.rindex(sub, start, end)
+    def rjust(self, width): return self.__class__(self.data.rjust(width))
+    def rstrip(self): return self.__class__(self.data.rstrip())
+    def split(self, sep=None, maxsplit=-1): 
+        return self.data.split(sep, maxsplit)
+    def splitlines(self, maxsplit=-1): return self.data.splitlines(maxsplit)
+    def startswith(self, prefix, start=0, end=sys.maxint): 
+        return self.data.startswith(prefix, start, end)
+    def strip(self): return self.__class__(self.data.strip())
+    def swapcase(self): return self.__class__(self.data.swapcase())
+    def title(self): return self.__class__(self.data.title())
+    def translate(self, table, deletechars=""): 
+        return self.__class__(self.data.translate(table, deletechars))
+    def upper(self): return self.__class__(self.data.upper())
+
+class MutableString(UserString):
+    """mutable string objects
+
+    Python strings are immutable objects.  This has the advantage, that
+    strings may be used as dictionary keys.  If this property isn't needed
+    and you insist on changing string values in place instead, you may cheat
+    and use MutableString.
+
+    But the purpose of this class is an educational one: to prevent
+    people from inventing their own mutable string class derived
+    from UserString and than forget thereby to remove (override) the
+    __hash__ method inherited from ^UserString.  This would lead to
+    errors that would be very hard to track down.
+
+    A faster and better solution is to rewrite your program using lists."""
+    def __init__(self, string=""):
+        self.data = string
+    def __hash__(self): 
+        raise TypeError, "unhashable type (it is mutable)"
+    def __setitem__(self, index, sub):
+        if index < 0 or index >= len(self.data): raise IndexError
+        self.data = self.data[:index] + sub + self.data[index+1:]
+    def __delitem__(self, index):
+        if index < 0 or index >= len(self.data): raise IndexError
+        self.data = self.data[:index] + self.data[index+1:]
+    def __setslice__(self, start, end, sub):
+        start = max(start, 0); end = max(end, 0)
+        if isinstance(sub, UserString):
+            self.data = self.data[:start]+sub.data+self.data[end:]
+        elif isinstance(sub, StringType) or isinstance(sub, UnicodeType):
+            self.data = self.data[:start]+sub+self.data[end:]
+        else:
+            self.data =  self.data[:start]+str(sub)+self.data[end:]
+    def __delslice__(self, start, end):
+        start = max(start, 0); end = max(end, 0)
+        self.data = self.data[:start] + self.data[end:]
+    def immutable(self):
+        return UserString(self.data)
+    
+if __name__ == "__main__":
+    # execute the regression test to stdout, if called as a script:
+    import os
+    called_in_dir, called_as = os.path.split(sys.argv[0])
+    called_in_dir = os.path.abspath(called_in_dir)
+    called_as, py = os.path.splitext(called_as)
+    sys.path.append(os.path.join(called_in_dir, 'test'))
+    if '-q' in sys.argv:
+        import test_support
+        test_support.verbose = 0
+    __import__('test_' + called_as.lower())