Python S-expression emulation using tuple-like objects.
Project description
etuples
Python S-expression emulation using tuple-like objects.
Examples
etuple
s are like tuples:
>>> from operator import add >>> from etuples import etuple, etuplize >>> et = etuple(add, 1, 2) >>> et ExpressionTuple((<built-in function add>, 1, 2)) >>> from IPython.lib.pretty import pprint >>> pprint(et) e(<function _operator.add(a, b, /)>, 1, 2) >>> et[0:2] ExpressionTuple((<built-in function add>, 1))
etuple
s can also be evaluated:
>>> et.evaled_obj 3
Evaluated etuple
s are cached:
>>> et = etuple(add, "a", "b") >>> et.evaled_obj 'ab' >>> et.evaled_obj is et.evaled_obj True
Reconstructed etuple
s and their evaluation results are preserved across tuple operations:
>>> et_new = (et[0],) + et[1:] >>> et_new is et True >>> et_new.evaled_obj is et.evaled_obj True
rator
, rands
, and apply
will return the operator, the operands, and apply the operation to the operands:
>>> from etuples import rator, rands, apply >>> et = etuple(add, 1, 2) >>> rator(et) <built-in function add> >>> rands(et) ExpressionTuple((1, 2)) >>> apply(rator(et), rands(et)) 3
rator
and rands
are multipledispatch
functions that can be extended to handle arbitrary objects:
from etuples.core import ExpressionTuple from collections.abc import Sequence class Node: def __init__(self, rator, rands): self.rator, self.rands = rator, rands def __eq__(self, other): return self.rator == other.rator and self.rands == other.rands class Operator: def __init__(self, op_name): self.op_name = op_name def __call__(self, *args): return Node(Operator(self.op_name), args) def __repr__(self): return self.op_name def __eq__(self, other): return self.op_name == other.op_name rands.add((Node,), lambda x: x.rands) rator.add((Node,), lambda x: x.rator) @apply.register(Operator, (Sequence, ExpressionTuple)) def apply_Operator(rator, rands): return Node(rator, rands)
>>> mul_op, add_op = Operator("*"), Operator("+") >>> mul_node = Node(mul_op, [1, 2]) >>> add_node = Node(add_op, [mul_node, 3])
etuplize
will convert non-tuple objects into their corresponding etuple
form:
>>> et = etuplize(add_node) >>> pprint(et) e(+, e(*, 1, 2), 3) >>> et.evaled_obj is add_node True
etuplize
can also do shallow object-to-etuple
conversions:
>>> et = etuplize(add_node, shallow=True) >>> pprint(et) e(+, <__main__.Node at 0x7f347361a080>, 3)
Installation
Using pip
:
pip install etuples
Development
First obtain the project source:
git clone git@github.com:pythological/etuples.git
Create a virtual environment and install the development dependencies:
$ pip install -r requirements.txt
Set up pre-commit
hooks:
$ pre-commit install --install-hooks
Tests can be run with the provided Makefile
:
make check
Project details
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.