Input Algorithms

A DSL to assist with writing specifications describing valid data and testing that inputted data meets those defined specifications.

Why the name?

I got the inspiration from the movie Transcendence when a character says something to the effect of “We could do this if we had better input algorithms”.


Use pip!:

pip install input_algorithms

Or if you’re developing it:

pip install -e .
pip install -e ".[tests]"


Here is an example to help you use the library.

from input_algorithms.validators import Validator
from input_algorithms.dictobj import dictobj
from input_algorithms import spec_base as sb
from input_algorithms.meta import Meta
import re

meta = Meta({},[])

# 1. Create a class defining your fields.
class PersonDictObj(dictobj):
    fields = ["name", "age"]

# 2. Create custom validate methods as required.
class ValidName(Validator):
    def validate(self, meta, val):
        matcher = re.compile("^[A-Za-z\ ]+$")
        if not matcher.match(val):
            raise Exception("{0} doesn't look like a name.".format(val))
        return val

class ValidAge(Validator):
    def validate(self, meta, val):
        if val > 120:
            raise Exception("I don't believe you are that old")
        return val

# 3. Tie together the pieces.
person_spec = sb.create_spec(
    name = sb.required(sb.valid_string_spec(ValidName())),
    age = sb.and_spec(sb.integer_spec(), ValidAge()),

# 4. Have some data
data = {"name": "Ralph", "age": 23}

# 5. Normalise the data into your object
normalised = person_spec.normalise(meta, data)

# 6. Use the object!
print("Name is {0}".format(
print("Age is {0}".format(normalised.age))


To run the tests in this project, just use the helpful script:


Or run tox: