Show HN: Calgebra – Set algebra for calendars in Python

2 comments

• ashenfad 2 days ago
  calgebra lets you compose calendar timelines using Python's set operators: | (union), & (intersection), - (difference), and ~ (complement).

  Queries are lazy—you build expressions first, then execute via slicing.

  Example – find when a team is free for a 2+ hour meeting:

    from calgebra import day_of_week, time_of_day, hours, HOUR
  
    # Define business hours
    weekend = day_of_week(["saturday", "sunday"], tz="US/Pacific")
    weekdays = ~weekend
    business_hours = weekdays & time_of_day(start=9*HOUR, duration=8*HOUR, tz="US/Pacific")
  
    # Team calendars (Google Calendar, .ics files, etc.)
    team_busy = alice | bob | charlie
  
    # One expression to find available slots
    free_slots = (business_hours - team_busy) & (hours >= 2)
  

  Features:

  - Set operations on any timeline source

  - Recurring patterns via RFC 5545 (dateutil under the hood)

  - Filter by duration, metadata, or custom properties

  - Google Calendar read/write

  - iCalendar (.ics) import/export

  Fwiw, I think focused DSLs are a great pairing with code-focused agents like huggingface's smol-agents or agex (my other hobby project).

  Video of a calgebra-enabled agent: https://youtu.be/10kG4tw0D4k

  Would love feedback!
• maomaomiumiu 1 day ago
  Pretty cool! A small but useful library for working with calendar intervals and schedules in Python