Serializable fn._

[EntilZha]

It would be useful for the underscore function to be serializable. The two primary use cases would be pickling for storage, but more commonly pickling to execute a function in parallel.

The following doesn't work using pickle or the more powerful dill package:

import pickle
import dill
from fn import _ as X

pickle.dumps(X + 1)
# ArityError: getattr((_ + 1), '__getstate__') expected 1 arguments, got 0

dill.dumps(X + 1)
# ArityError: getattr((_ + 1), '__getstate__') expected 1 arguments, got 0

f = X + 1
pickle.dumps(f)
# ArityError: getattr((_ + 1), '__getstate__') expected 1 arguments, got 0

dill.dumps(f)
# ArityError: getattr((_ + 1), '__getstate__') expected 1 arguments, got 0

dill.loads(dill.dumps(lambda x: x + 1))(1)
#2

My very specific use case is for https://github.com/EntilZha/PyFunctional where you can do this to run a map in parallel:

from functional import pseq

# This doesn't work
pseq.range(4).map(X + 1)

# This works
pseq.range(4).map(lambda x: x + 1)

[low-ghost]

Great idea! You're right, would definitely improve pickle/dill cases and especially true of parallel execution

[cgarciae]

I think this is issue is critical for using fn.py with spark.