About this module

Wrapper module which provides iterable object with infix style method chaining.

Unreadble:

>>> filter(lambda y: y % 2, map(lambda x: x + 1, iterable))

Readable:

>>> iterable = react(iterable)
>>> iterable.map(lambda x: x + 1).filter(lambda y: y % 2)

How to install

Requires python2.6 or later (include python3.x). You need pip or distribute or setuptools:

$ pip install chainreaction

or use easy_install:

$ easy_install chainreaction

Recent changed

How to use

The simplest and an only way to use this module is to call the react function. react is a factory function which looks up ‘__iter__’ / ‘__getitem__’ from an given iterable, and returns wrapped object.

Example to use:

>>> from chainreaction.reactor import react
>>> react("hello")
>>> react([1, 2, 3])
>>> react(iter([1, 2, 3])
>>> class DictLike(dict):pass
>>> react(DictLike())

Chainable object support any methods of its wrapped object, and try to wrap their return value. By convention, side effective methods return nothing, but chainable object returns its side affected object wrapped with appropriate wrappper. If iterator was passed into react, it would be consumed when it called any iterative methods.

Example to use:

>>> tobewrapped = "hello"
>>> wrapped = react(tobewrapped)
>>> wrapped = wrapped.upper().map(lambda c: ord(c))
>>> [chr(c) for c in wrapped.unwrap] = [c for c in tobewrapped.upper()]
True
>>> tobewrapped = [1, 2, 3]
>>> wrapped = react(tobewrapped)
>>> wrapped.append(4).count()
4
>>> len(tobewrapped)
4

If an iterator was given, this iterator would be consumed when it called any method:

>>> tobewrapped = iter([1,2,3])
>>> wrapped = react(tobewrapped)
>>> wrapped.count()
4
>>> len(list(tobewrapped))
0

Tiny percent encoding implementation example:

>>> test = bytes("hello world-._~", encoding="UTF-8")
>>> wrapped = react(test)
>>> safe = set()
>>> react("0123456789").foreach(lambda c: safe.add(ord(c)))
>>> react(range(ord('a'), ord('z') + 1)).foreach(lambda b: safe.add(b))
>>> react(range(ord('A'), ord('Z') + 1)).foreach(lambda b: safe.add(b))
>>> react("-._~").foreach(lambda c: safe.add(ord(c)))
>>> test = wrapped.map(lambda b: b if b > 0 else 256 + b)
>>> test = test.map(lambda i: '+' if chr(i).isspace() else chr(i) if i in safe else "%{0:x}".format(i))
>>> test.tostring == "hello+world-._~"
True

Basic API

• unwrap

  Retrieves iterable from wrapped object.

• dump

  Elements dump.

• isiterator

  True if wrapped object is iterator.

• tostring

  Returns almost same with “”.join((str(x) for x in iterable)). This method always returns str object. str wrapped returns unwrapped, bytes or bytearray wrapped returns str converted, dict wrapped returns “key=value” pairs joined with “&”.

• foreach(f)

  Applies a given f to all elements.

• filter(pred)

  Selects all elements which satisfy a given predicate.

• map(f)

  Builds a new collection by applying a given f.

• forall(pred)

  True if all elements satisfy a given predicate.

• forany(pred)

  True if any elements satisfy a given predicate.

• dropwhile(pred)

  Drops longest prefix of elements that satisfy a given predicate.

• dropright(pred)

  Drops longest suffix of elements that satisfy a given predicate.

• takwhile(pred)

  Takes longest prefix of elements that satisfy a given predicate.

• takeright(pred)

  Takes longest suffix of elements that satisfy a given predicate.

• mkstring(joiner=””)

  Returns wrapped str object using a joiner string.

• counts(pred=lambda x: True)

  Counts the number of elements that satisfy a given predicate.

• contains(key)

  Tests whether this wrapped object contains a given key as an element.

• reduce(f)

  Returns a value(not wrapped) using a given f.