calgebra 0.10.9

A tiny DSL for calendar interval algebra - compose, filter, and query time ranges using set operations.

calgebra 🗓️

Set algebra for calendars. Compose lazily and query efficiently.

Installation

pip install calgebra

# Or with Google Calendar support
pip install calgebra[google-calendar]

# Or with iCalendar (.ics) file support
pip install calgebra[ical]

Quick Start

from calgebra import day_of_week, time_of_day, at_tz, pprint, hours, HOUR
from itertools import islice

tz = "US/Pacific"
at = at_tz(tz)

# Team calendars
alice, bob, charlie = ...  # Timeline objects (Google Calendar, .ics files, etc.)

# Define when work happens
weekend = day_of_week(["saturday", "sunday"], tz=tz)
weekdays = ~weekend
workhours = time_of_day(start=9*HOUR, duration=8*HOUR, tz=tz)
business_hours = weekdays & workhours

# When is anyone busy?
team_busy = alice | bob | charlie

# Free slots: business hours minus busy, at least 2 hours
free_slots = (business_hours - team_busy) & (hours >= 2)

# Query January 2025
pprint(islice(free_slots[at("2025-01-01"):at("2025-02-01")], 5), tz=tz)
# 2025-01-06 14:00:00 -> 2025-01-06 17:00:00
# 2025-01-08 09:00:00 -> 2025-01-08 12:00:00
# ...

Core Features:

• Set operations: | (union), & (intersection), - (difference), ~ (complement)
• Lazy composition: Build complex queries, execute with slicing
• Recurring patterns: day_of_week(), time_of_day(), recurring() (RFC 5545)
• Interval filtering: hours >= 2, summary == "standup", custom properties
• Google Calendar: Read/write via calgebra.gcsa
• iCalendar (.ics): Load/save standard RFC 5545 files

→ Quick-start | Tutorial | API Reference | Google Calendar | Demo Video

License

MIT License - see LICENSE file for details.