Morrow.mojo

Human-friendly date and time utilities for Mojo. Morrow provides an Arrow-inspired API for creating, parsing, formatting, shifting, comparing, and humanizing date-time values.

Language: English | 中文

Documentation: https://mojoto.github.io/morrow.mojo/

Installation

Morrow is available from the official Modular Community channel. From a Pixi workspace already configured for Mojo, add the Modular Community channel and install Morrow:

pixi workspace channel add --prepend https://repo.prefix.dev/modular-community
pixi add morrow

The package installs a compiler-compatible morrow.mojoc into the active Pixi environment, so it can be imported without copying source files.

Usage

Paste the following example into the REPL:

from morrow import FORMAT_RSS, Morrow, TimeZone

var now = Morrow.now()
print(now)

var utc = Morrow.utcnow()
print(utc)

var parsed = Morrow.get("2026-01-01 03:04:05Z")
print(parsed)
print(parsed.format("YYYY-MM-DD HH:mm:ss ZZ"))

var beijing = parsed.to("+08:00")
print(beijing)

var hour = beijing.span("hour")
print(hour)

print(beijing.isocalendar())
print(beijing.timetuple())

var rss = Morrow(2026, 1, 1, 10, 30, 35, 0, TimeZone(0, "UTC"))
print(rss.format(FORMAT_RSS))

Morrow is UTC by default, supports fixed-offset time zones, parses ISO 8601 strings and POSIX timestamps, and formats values with Arrow-style tokens or Python-style strftime.

Development

Run make help to list the available targets.

Target	Description
make install	Create or reuse .venv and install the pinned Mojo version with uv
make test	Run every tests/test_*.mojo file
make format	Format the morrow and tests directories
make build	Precompile morrow as morrow.mojoc
make package	Build the distributable Conda package with rattler-build
make clean	Remove morrow.mojoc
make doc-install	Install Docusaurus dependencies
make doc-build	Build the Docusaurus static site
make doc-serve	Serve the built Docusaurus site
make doc-clean	Remove generated Docusaurus files

The documentation targets require Node.js and npm. Run make doc-install before building the documentation, then use make doc-build followed by make doc-serve to preview the built site.