• Stars
    star
    2,587
  • Rank 17,718 (Top 0.4 %)
  • Language
    Go
  • License
    MIT License
  • Created over 2 years ago
  • Updated 2 months ago

Reviews

There are no reviews yet. Be the first to send feedback to the community and the maintainers!

Repository Details

🦄 Monads and popular FP abstractions, powered by Go 1.18+ Generics (Option, Result, Either...)

mo - Monads

tag Go Version GoDoc Build Status Go report Coverage License

🦄 samber/mo brings monads and popular FP abstractions to Go projects. samber/mo uses the recent Go 1.18+ Generics.

Inspired by:

  • Scala
  • Rust
  • FP-TS

See also:

  • samber/lo: A Lodash-style Go library based on Go 1.18+ Generics
  • samber/do: A dependency injection toolkit based on Go 1.18+ Generics

Why this name?

I love short name for such utility library. This name is similar to "Monad Go" and no Go package currently uses this name.

💡 Features

We currently support the following data types:

  • Option[T] (Maybe)
  • Result[T]
  • Either[A, B]
  • EitherX[T1, ..., TX] (With X between 3 and 5)
  • Future[T]
  • IO[T]
  • IOEither[T]
  • Task[T]
  • TaskEither[T]
  • State[S, A]

🚀 Install

go get github.com/samber/mo@v1

This library is v1 and follows SemVer strictly.

No breaking changes will be made to exported APIs before v2.0.0.

This library has no dependencies except the Go std lib.

💡 Quick start

You can import mo using:

import (
    "github.com/samber/mo"
)

Then use one of the helpers below:

option1 := mo.Some(42)
// Some(42)

option1.
    FlatMap(func (value int) Option[int] {
        return Some(value*2)
    }).
    FlatMap(func (value int) Option[int] {
        return Some(value%2)
    }).
    FlatMap(func (value int) Option[int] {
        return Some(value+21)
    }).
    OrElse(1234)
// 21

option2 := mo.None[int]()
// None

option2.OrElse(1234)
// 1234

option3 := option1.Match(
    func(i int) (int, bool) {
        // when value is present
        return i * 2, true
    },
    func() (int, bool) {
        // when value is absent
        return 0, false
    },
)
// Some(42)

More examples in documentation.

Tips for lazy developers

I cannot recommend it, but in case you are too lazy for repeating mo. everywhere, you can import the entire library into the namespace.

import (
    . "github.com/samber/mo"
)

I take no responsibility on this junk. 😁 💩

🤠 Documentation and examples

GoDoc: https://godoc.org/github.com/samber/mo

Option[T any]

Option is a container for an optional value of type T. If value exists, Option is of type Some. If the value is absent, Option is of type None.

Constructors:

Methods:

Result[T any]

Result respresent a result of an action having one of the following output: success or failure. An instance of Result is an instance of either Ok or Err. It could be compared to Either[error, T].

Constructors:

Methods:

Either[L any, R any]

Either respresents a value of 2 possible types. An instance of Either is an instance of either A or B.

Constructors:

  • mo.Left() doc
  • mo.Right() doc

Methods:

  • .IsLeft() doc
  • .IsRight() doc
  • .Left() doc
  • .Right() doc
  • .MustLeft() doc
  • .MustRight() doc
  • .Unpack() doc
  • .LeftOrElse() doc
  • .RightOrElse() doc
  • .LeftOrEmpty() doc
  • .RightOrEmpty() doc
  • .Swap() doc
  • .ForEach() doc
  • .Match() doc
  • .MapLeft() doc
  • .MapRight() doc

EitherX[T1, ..., TX] (With X between 3 and 5)

EitherX respresents a value of X possible types. For example, an Either3 value is either T1, T2 or T3.

Constructors:

  • mo.NewEitherXArgY() doc. Eg:
    • mo.NewEither3Arg1[A, B, C](A)
    • mo.NewEither3Arg2[A, B, C](B)
    • mo.NewEither3Arg3[A, B, C](C)
    • mo.NewEither4Arg1[A, B, C, D](A)
    • mo.NewEither4Arg2[A, B, C, D](B)
    • ...

Methods:

  • .IsArgX() doc
  • .ArgX() doc
  • .MustArgX() doc
  • .Unpack() doc
  • .ArgXOrElse() doc
  • .ArgXOrEmpty() doc
  • .ForEach() doc
  • .Match() doc
  • .MapArgX() doc

Future[T any]

Future represents a value which may or may not currently be available, but will be available at some point, or an exception if that value could not be made available.

Constructors:

  • mo.NewFuture() doc

Methods:

IO[T any]

IO represents a non-deterministic synchronous computation that can cause side effects, yields a value of type R and never fails.

Constructors:

  • mo.NewIO() doc
  • mo.NewIO1() doc
  • mo.NewIO2() doc
  • mo.NewIO3() doc
  • mo.NewIO4() doc
  • mo.NewIO5() doc

Methods:

IOEither[T any]

IO represents a non-deterministic synchronous computation that can cause side effects, yields a value of type R and can fail.

Constructors:

  • mo.NewIOEither() doc
  • mo.NewIOEither1() doc
  • mo.NewIOEither2() doc
  • mo.NewIOEither3() doc
  • mo.NewIOEither4() doc
  • mo.NewIOEither5() doc

Methods:

Task[T any]

Task represents a non-deterministic asynchronous computation that can cause side effects, yields a value of type R and never fails.

Constructors:

  • mo.NewTask() doc
  • mo.NewTask1() doc
  • mo.NewTask2() doc
  • mo.NewTask3() doc
  • mo.NewTask4() doc
  • mo.NewTask5() doc
  • mo.NewTaskFromIO() doc
  • mo.NewTaskFromIO1() doc
  • mo.NewTaskFromIO2() doc
  • mo.NewTaskFromIO3() doc
  • mo.NewTaskFromIO4() doc
  • mo.NewTaskFromIO5() doc

Methods:

TaskEither[T any]

TaskEither represents a non-deterministic asynchronous computation that can cause side effects, yields a value of type R and can fail.

Constructors:

  • mo.NewTaskEither() doc
  • mo.NewTaskEitherFromIOEither() doc

Methods:

State[S any, A any]

State represents a function (S) -> (A, S), where S is state, A is result.

Constructors:

  • mo.NewState() doc
  • mo.ReturnState() doc

Methods:

🛩 Benchmark

// @TODO

This library does not use reflect package. We don't expect overhead.

🤝 Contributing

Don't hesitate ;)

With Docker

docker-compose run --rm dev

Without Docker

# Install some dev dependencies
make tools

# Run tests
make test
# or
make watch-test

👤 Contributors

Contributors

💫 Show your support

Give a ⭐️ if this project helped you!

GitHub Sponsors

📝 License

Copyright © 2022 Samuel Berthe.

This project is MIT licensed.

More Repositories

1

lo

💥 A Lodash-style Go library based on Go 1.18+ Generics (map, filter, contains, find...)
Go
17,419
star
2

awesome-prometheus-alerts

🚨 Collection of Prometheus alerting rules
HTML
6,502
star
3

do

⚙️ A dependency injection toolkit based on Go 1.18+ Generics.
Go
1,807
star
4

oops

🔥 Error handling library with context, assertion, stack trace and source fragments
Go
384
star
5

slog-multi

🚨 Design workflows of slog handlers: pipeline, middleware, fanout, routing, failover, load balancing...
Go
342
star
6

invoice-as-a-service

💰 Simple invoicing service (REST API): from JSON to PDF
PHP
181
star
7

sync-ssh-keys

🔐 Sync public ssh keys to ~/.ssh/authorized_keys, based on Github/Gitlab organization membership.
Go
138
star
8

slog-gin

🚨 Gin middleware for slog logger
Go
109
star
9

chartjs-plugin-datasource-prometheus

📊 Chart.js plugin for Prometheus
TypeScript
107
star
10

slog-formatter

🚨 slog: Attribute formatting
Go
107
star
11

slog-echo

🚨 Echo middleware for slog logger
Go
100
star
12

go-gpt-3-encoder

Go BPE tokenizer (Encoder+Decoder) for GPT2 and GPT3
Go
78
star
13

the-great-gpt-firewall

🤖 A curated list of websites that restrict access to AI Agents, AI crawlers and GPTs
Python
75
star
14

prometheus-query-js

📊 A Javascript client for Prometheus query API
TypeScript
58
star
15

hot

🌶️ In-memory caching library for Go
Go
58
star
16

github-actions-runner

✅ Docker images for starting self-hosted Github Actions runner(s).
Dockerfile
57
star
17

slog-fiber

🚨 Fiber middleware for slog logger
Go
52
star
18

slog-sampling

🚨 slog sampling: drop repetitive log records
Go
49
star
19

slog-chi

🚨 Chi middleware for slog logger
Go
43
star
20

slog-sentry

🚨 slog: Sentry handler
Go
43
star
21

awesome-olap

A curated list of awesome Online Analytical Processing databases, frameworks, ressources and other awesomeness.
37
star
22

grafana-flamegraph-panel

📊 Flame graph panels for Grafana
JavaScript
37
star
23

slog-loki

🚨 slog: Loki handler
Go
36
star
24

slog-http

🚨 net/http middleware for slog logger
Go
32
star
25

slog-zerolog

🚨 slog: Zerolog handler
Go
30
star
26

workshop-prometheus-grafana

📊 Prometheus and Grafana 101
JavaScript
30
star
27

slog-zap

🚨 slog: Zap handler
Go
23
star
28

go-metered-io

📐 A drop-in replacement to io.Reader and io.Writer with the total number of bytes transfered.
Go
23
star
29

go-amqp-pubsub

Fault tolerant Pub/Sub library for RabbitMQ
Go
21
star
30

go-singleflightx

🧬 x/sync/singleflight but with generics, batching, sharding and nullable result
Go
19
star
31

slog-logrus

🚨 slog: Logrus handler
Go
18
star
32

slog-slack

🚨 slog: Slack handler
Go
18
star
33

arp-spoofing

💥 Simple implementation of arp poisoning attack ;)
C
16
star
34

pg_cron

⏰ PostgreSQL extension for running periodic jobs
C
15
star
35

go-tcp-pool

✨ Drop-in replacement to net.Conn with pooling and auto-reconnect
Go
14
star
36

go-type-to-string

🕵️‍♂️ Extract a string representation of Go type
Go
14
star
37

slog-syslog

🚨 slog: Syslog handler
Go
13
star
38

refined-hn

JavaScript
11
star
39

git-contrib-graph

📊 Displays a github-like contribution graph, of every contributors of a repository
Go
10
star
40

slog-nats

🚨 slog: NATS handler
Go
10
star
41

slog-parquet

🚨 slog: Parquet handler + Object Storage
Go
10
star
42

slog-datadog

🚨 slog: Datadog handler
Go
10
star
43

free_proxy_list

Free proxy list [NOT MAINTAINED ANYMORE - please fork]
Shell
9
star
44

slog-otel

OTEL toolchain for slog
Makefile
8
star
45

slog-graylog

🚨 slog: Graylog handler
Go
7
star
46

powEUr

Python
7
star
47

slog-telegram

🚨 slog: Telegram handler
Go
7
star
48

node-promfiler

Expose a http endpoint for exporting node.js v8 profiling
JavaScript
7
star
49

slog-webhook

🚨 slog: Webhook handler
Go
7
star
50

slog-betterstack

🚨 slog: Betterstack handler
Go
7
star
51

slog-common

Common toolchain for slog
Go
6
star
52

slog-kafka

🚨 slog: Kafka handler
Go
6
star
53

slog-channel

🚨 slog: Go channel handler
Go
6
star
54

slog-logstash

🚨 slog: Logstash handler
Go
5
star
55

ansible-role-airbyte

Ansible role for Airbyte
5
star
56

slog-fluentd

🚨 slog: Fluentd handler
Go
4
star
57

remote-dev-environment

👨‍💻 My development environment is too slow, let's fix that !
4
star
58

GoogleCalendarNotifier-FitbitTracker

Google Calendar notifier for Fitbit Tracker
Gosu
4
star
59

slog-mock

🚨 slog: mock handler
Go
4
star
60

slog-quickwit

🚨 slog: Quickwit handler
Go
4
star
61

criterion-rpm-package

RPM package for Criterion (C unit testing)
Shell
3
star
62

dagobert

A simple Go client for the clip-as-service server
Go
3
star
63

rabbitmq-flooding

Cluster recovery testing. Floods RabbitMQ with random data.
Python
3
star
64

go-psi

🥵 Pressure Stall Informations (PSI) and starvation notifier
Go
3
star
65

slog-microsoft-teams

🚨 slog: Microsoft Teams handler
Go
3
star
66

llvm_dart_binding

Binding Dart/LLVM (using LLVM bytecode from Dart)
Dart
3
star
67

lab-langchain-getting-started

Python
2
star
68

BTCC_api

A basic API wrapper for the BTCC Trading and Market FIX API.
JavaScript
2
star
69

ngx-domarrow

Declarative and template-driven DOMArrow integration for Angular2+
TypeScript
2
star
70

github-stackoverflow-email-scrapping

Scrape top Github and Stack-Overflow users to find email address
Go
2
star
71

nft-http-api

🚦 NFT over HTTP API
Go
2
star
72

go-quickwit

🍱 A Go ingestion client for Quickwit
Go
2
star
73

celery_demonstration

Async worker + scheduling
Python
2
star
74

dockerfiles

Dockerfile
1
star
75

SaaS-Cookbook-List

List of Cookbook about SaaS development (ENG/FR)
1
star
76

dotfiles

@samber's dotfiles
JavaScript
1
star
77

grafana-dashboard-nomad

Grafana dashboards for Nomad (Docker orchestrator from Hashicorp)
1
star
78

go-clevercloud-api

Go library for Clever-Cloud api
Go
1
star
79

lab-langchain

Python
1
star
80

slog-mattermost

🚨 slog: Mattermost handler
Go
1
star
81

jitsi-virtual-background

JavaScript
1
star
82

raw-ip-udp-sockets-chap

Simple implementation of CHAP protocol, with raw socket layers (3+4)
C
1
star
83

lab-parquet

Go
1
star
84

canvas-to-bmp

TypeScript
1
star
85

refined-cycle-app

JavaScript
1
star
86

azure-ad-oauth2-proxy

Dockerfile
1
star
87

packer-qemu-debian

Builds Debian 8 image for Qemu
Shell
1
star
88

poc-selenium-unit-test-css

Python
1
star
89

maxscale-experiments

Demonstration step-by-step of MaxScale for master/slave query spliting/routing #mysql #docker
Shell
1
star
90

google-takeout-to-s3

🚨 Simple script to upload encrypted Google Takeout archives to S3.
1
star
91

messenger-bot-clock

Messenger bot replying with current time
JavaScript
1
star
92

fb-messenger-bot-psychologist

🤖 A Messenger bot talking like a psychologist
Emacs Lisp
1
star
93

promql-exporter

Prometheus exporter for PromQL endpoints (replacing federation and remote-write)
Go
1
star