python-bond 0.2

A simple example

>>> # Let's bond with a PHP interpreter
>>> from bond.PHP import PHP
>>> php = PHP()
>>> php.eval_block('echo "Hello world!\n";')
Hello world!

>>> # Make an expensive split function using PHP's explode
>>> split = php.callable('explode')
>>> split(' ', "Hello world splitted by PHP!")
[u'Hello', u'world', u'splitted', u'by', u'PHP!']

>>> # Call Python from PHP
>>> def call_me():
...     print("Hi, this is Python talking!")
>>> php.export(call_me)
>>> php.eval('call_me()')
Hi, this is Python talking!

>>> # Use some remote resources
>>> remote_php = PHP('ssh remote php')
>>> remote_php.eval_block('function call_me() { echo "Hi from " . system("hostname") . "!"; }')
>>> remote_php.eval('call_me()')
Hi from remote!

>>> # Bridge two worlds!
>>> from bond.Perl import Perl
>>> perl = Perl()
>>> php.proxy('explode', perl)
>>> # note: explode is now available to Perl
>>> perl.eval('explode("=", "Mind=blown!")')
[u'Mind', u'blown!']

Why?

I needed bond for refactoring a large PHP project, mostly. With bond you can rewrite your program incrementally, while still executing all your existing code unchanged. You can start by rewriting just a single function:

from bond.PHP import PHP
import sys

php = PHP()
php.eval_block('include("my_original_program.php");')

def new_function(arg)
   # do something here
   pass

php.export(new_function, 'function_to_be_replaced')
php.call('main', sys.argv)

It turns out that the same approach can be useful to perform remote computation as well. The wire protocol is simple enough to be extended to any language supporting an interactive interpreter.

API

The bond class supports the following methods:

eval(code):

Evaluate and return the value of a single statement of code in the interpreter.

eval_block(code):

Execute a “code” block inside the interpreter. Any construct which is legal by the current interpreter is allowed. Nothing is returned.

close():

Terminate the communication with the interpreter.

call(name, *args):

Call a function “name” in the interpreter using the supplied list of arguments *args (apply *args to a callable statement defined by “name”). The arguments are automatically converted to their other language’s counterpart. The return value is captured and converted back to Python as well.

callable(name):

Return a function that calls “name”:

explode = php.callable('explode')
# Now you can call explode as a normal, local function
explode(' ', 'Hello world')

export(func, name):

Export a local function “func” so that can be called on the remote language as “name”. If “name” is not specified, use the local function name directly. Note that “func” must be a function reference, not a function name.

proxy(name, other, remote):

Export a function “name” from the current bond to “other”, named as “remote”. If “remote” is not provided, the same value as “name” is used.

interact():

Start an interactive session with the underlying interpreter. By default, all input lines are executed with bond.eval_block(). If “!” is pre-pended, execute a single statement with bond.eval() and print it’s return value.

You can construct a bond by using the appropriate subclass:

from bond.<language> import <language>
interpreter = <language>().

Language support

Authors and Copyright

python-bond’s GIT repository is publicly accessible at:

git://src.thregr.org/python-bond

or at GitHub.