ibis-enum 0.2.0

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ibis-enum

ibis-enum provides a single utility: IbisEnum. It is like a plain enum.Enum, except it has better interoperability with ibis. It is modeled after ordered enums in DuckDB, PostgreSQL, and MySQL.

• They are have an ordering, eg Priority.LOW < Priority.MEDIUM < Priority.HIGH
• They provide useful conversion methods to convert between the string-y and int-y representations.
• They can be compared against both plain python and ibis values, with sane coercion that is friendly but hopefully avoids footguns. eg Priority.LOW < ibis.literal("HIGH") works as expected, resulting in an ibis BooleanValue expression that would execute to True. Note that plain string comparison of "LOW" < "HIGH" would evaluate to False!
• They have great type annotations!
• They are well-tested, linted, and formatted.
• MIT licensed.

I would consider this as being in Beta status. It is pretty simple, and I would trust it's implementation to be mostly bug free, and I don't see TOO many reasons to change the public API, but I probably still will alittle bit. So to keep me from breaking you, use a lockfile.

Installation

Available on PyPI as ibis-enum.

uv add ibis-enum

Quick Start

from ibis_enum import IbisEnum

class Priority(IbisEnum):
	# Values must be ints. The order of the members is determined by the ints.
    LOW = 0
    MEDIUM = 1
    HIGH = 2
    URGENT = 3
	# Names are case sensitive:
	# low = 5 would result in a distinct enum value
	
	# Member values MUST be unique.
	# ALSO_MEDIUM = 1 # This would error

Creation

Using plain python values:

assert Priority.MEDIUM == Priority("MEDIUM")
assert Priority.MEDIUM == Priority(1)
Priority("bogus") # errors
Priority(999) # errors
Priority("medium") # errors, case mismatch

Conversion

You can convert python values to the int-y or string-y form using classmethods:

assert Priority.to_stringy(Priority.MEDIUM) == "MEDIUM"
assert Priority.to_stringy("MEDIUM") == "MEDIUM"
assert Priority.to_stringy(1) == "MEDIUM"

assert Priority.to_integery(Priority.MEDIUM) == 1
assert Priority.to_integery("MEDIUM") == 1
assert Priority.to_integery(1) == 1

And you can convert ibis values, which give you back ibis StringValue and IntegerValues:

assert Priority.to_stringy(ibis.literal("MEDIUM")).execute() == "MEDIUM"
assert Priority.to_stringy(ibis.literal(1)).execute() == "MEDIUM"

assert Priority.to_integery(ibis.literal("MEDIUM")).execute() == 1
assert Priority.to_integery(ibis.literal(1)).execute() == 1

Comparison and Ordering

IbisEnum members can be compared to other IbisEnums, plain python ints and strs which give back plain bools as you would expect:

assert Priority.LOW < Priority.HIGH
assert Priority.LOW < "HIGH"
assert Priority.LOW < 2

Comparing to an ibis Value results in an ibis BooleanValue. Any StringValue's are converted to the integer level when ordering is important! Otherwise we avoid casting whenever we don't need it, for optimal performance.

assert (Priority.LOW == ibis.literal("HIGH")).execute() is True
assert (Priority.LOW < ibis.literal(2)).execute() is True

Comparison Warning

For comparisons with Ibis values, the enum member MUST be on the left-hand side:

Priority.HIGH == ibis.literal(1)
Priority.HIGH > ibis.literal(1)
# etc

The reverse form may fail:

ibis.literal(1) == Priority.HIGH
ibis.literal(1) < Priority.HIGH
# etc

This is due a limitation of Ibis that we don't have control over. When python sees X == Y, it first calls X.__eq__(Y), then if that returns NotImplemented then it falls back to Y.__eq__(X). ibis.Value.__eq__(self, <enum value>) throws an error instead of returning a NotImplemented as it probably should. So, we need instead for Enum.__eq__(self, <ibis value>) to be the comparison operator caled first. To guarantee this, the enum needs to be on the left hand side of the comparison.

Why Not Plain Enum?

Built-in enum.Enum is fine for Python-only comparisons, but it does not know how to compare itself to Ibis expressions.

import enum
import ibis

class PlainPriority(enum.Enum):
    LOW = 0
    MEDIUM = 1
    HIGH = 2
    URGENT = 3

# This would error!
Priority.HIGH == ibis.literal(2)