Python code generation tool.
Literal is a fun weekend project to create a way to generate python code with Python code. Instead of having string literals of Python code, you use literal.py objects that remembers the operations done to them, and the history of operations is the resulting Python program.
This is just an experiment that I wanted to play with; It’s usefulness is not proven, and more than likely this will be thrown away as a failed experiment. So use with care and caution.
import literal @literal.py def unpack_octet(x, payload, offset, unpack_from): x <<= unpack_from('B', payload, offset) offset += 1 print(unpack_octet())
x = unpack_from('B', payload, offset) offset += 1
Or another example used to create argument unpackers for the AMQP protocol:
def unpack(method): @literal.py def body(p, payload, offset, unpack_from, argtuple, ssize): fields = method.fields names = p.tuple(*self.field_names) for i, fset in enumerate(fields): if len(fset) == 1: for field in fset: name = p.var(field.name) if field.format == '*': # This is a string payload, # don't have to unpack name <<= payload[offset:offset + ssize] offset += ssize else: # A single field to unpack name <<= unpack_from(struct_format(field.format), payload, offset) offset += field.size else: # A list of field to unpack these = p.tuple(*fset.names) these <<= unpack_from(struct_format(fset.format), payload, offset) offset += sum(f.size for f in fset) return names return body().as_fun(lambda payload, offset: 1, method.name)
Would generate the following code for the AMQP method basic_deliver:
def deliver(payload, offset): ssize = unpack_from('B', payload, offset) offset += 1 consumer_tag = payload[offset:offset + ssize] offset += ssize delivery_tag, redelivered, ssize = unpack_from('QBB', payload, offset) offset += 10 exchange = payload[offset:offset + ssize] offset += ssize ssize = unpack_from('B', payload, offset) offset += 1 routing_key = payload[offset:offset + ssize] offset += ssize return (consumer_tag, delivery_tag, redelivered, exchange, routing_key)
More documentation to come.
You can install literal either via the Python Package Index (PyPI) or from source.
To install using pip,:
$ pip install literal
To install using easy_install,:
$ easy_install literal
If you have downloaded a source tarball you can install it by doing the following,:
$ python setup.py build # python setup.py install # as root
If you have any suggestions, bug reports or annoyances please report them to our issue tracker at http://github.com/ask/literal.py/issues/
Development of literal.py happens at Github: http://github.com/ask/literal.py
You are highly encouraged to participate in the development. If you don’t like Github (for some reason) you’re welcome to send regular patches.
This software is licensed under the New BSD License. See the LICENSE file in the top distribution directory for the full license text.