A simple and dirty way to define generic methods to existing types.
Project description
It provides a simple and dirty way to define generic methods to existing types. You can make overloaded methods using this.
Compatibility
TypeQuery does not depend on any non-standard libraries. It works on these environments:
Python 2.5 to 3.2
CPython, Stackless, PyPy, Jython
Install
Install using pip:
$ pip install TypeQuery
or easy_install:
$ easy_install TypeQuery
Example: JSON encoder
from typequery import GenericMethod
from sys import version_info
from re import sub
from numbers import Real
from collections import Mapping, Iterable
if version_info.major > 2:
basestring = string = str
else:
string = unicode
json = GenericMethod('serialize')
@json.of(type(None))
def json(value):
return 'null'
@json.of(bool)
def json(value):
return 'true' if value else 'false'
@json.of(Real)
def json(value):
return str(value)
@json.of(string)
def json(value):
def escape(match):
s = match.group(0)
if s in ('\\', '"', '\b', '\f', '\n', '\r', '\t'):
return '\\' + s
n = ord(s)
if n < 0x10000:
return r'\u%04x' % n
n -= 0x10000
s1 = 0xd800 | ((n >> 10) & 0x3ff)
s2 = 0xdc00 | (n & 0x3ff)
return r'\u%04x\u%04x' % (s1, s2)
return '"%s"' % sub(r'([\\"]|[^\ -~])', escape, value)
@json.of(Iterable)
def json(value):
return '[%s]' % ', '.join(json(element) for element in value)
@json.of(Mapping)
def json(value):
return '{%s}' % ', '.join('%s: %s' % (json(string(key)), json(value))
for key, value in value.items())
And defined json function works like:
>>> json(123)
'123'
>>> json(True)
'true'
>>> json({'apple': 3, 'banana': 5, 'carrot': 1})
'{"apple": 3, "banana": 5, "carrot": 1}'
As the above shows, you can define type-aware instance methods to existing types even including ABCs like collections.Iterable.
