golang-samber-mo

Name: golang-samber-mo
Author: samber

33kinstalls179forks

How to install golang-samber-mo?

samber/cc-skills-golang/golang-samber-mo

$npx -y skills add samber/cc-skills-golang --skill golang-samber-mo

Installs into the current project.

Summary

Monadic types for Golang using samber/mo — Option, Result, Either, Future, IO, Task, and State types for type-safe nullable values, error handling, and functional composition with pipeline sub-packages. Apply when using or adopting samber/mo, when the codebase imports `github.com

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SKILL.md

1	Persona: You are a Go engineer bringing functional programming safety to Go. You use monads to make impossible states unrepresentable — nil checks become type constraints, error handling becomes composable pipelines.
2
3	Thinking mode: Use `ultrathink` when designing multi-step Option/Result/Either pipelines. Wrong type choice creates unnecessary wrapping/unwrapping that defeats the purpose of monads.
4
5	# samber/mo — Monads and Functional Abstractions for Go
6
7	Go 1.18+ library providing type-safe monadic types with zero dependencies. Inspired by Scala, Rust, and fp-ts.
8
9	Official Resources:
10
11	- [pkg.go.dev/github.com/samber/mo](https://pkg.go.dev/github.com/samber/mo)
12	- [github.com/samber/mo](https://github.com/samber/mo)
13
14	This skill is not exhaustive. Please refer to library documentation and code examples for more information. For Go package docs, symbols, versions, importers, and known vulnerabilities, → See `samber/cc-skills-golang@golang-pkg-go-dev` skill (`godig`) — prefer it over Context7 for Go package facts. To navigate this library's usage in your own code (definitions, call sites, diagnostics), → See `samber/cc-skills-golang@golang-gopls` skill (`gopls`). Context7 remains a fallback for docs not indexed on pkg.go.dev.
15
16	```bash
17	go get github.com/samber/mo
18	```
19
20	For an introduction to functional programming concepts and why monads are valuable in Go, see [Monads Guide](./references/monads-guide.md).
21
22	## Core Types at a Glance
23
24	\| Type \| Purpose \| Think of it as... \|
25	\| --- \| --- \| --- \|
26	\| `Option[T]` \| Value that may be absent \| Rust's `Option`, Java's `Optional` \|
27	\| `Result[T]` \| Operation that may fail \| Rust's `Result<T, E>`, replaces `(T, error)` \|
28	\| `Either[L, R]` \| Value of one of two types \| Scala's `Either`, TypeScript discriminated union \|
29	\| `EitherX[L, R]` \| Value of one of X types \| Scala's `Either`, TypeScript discriminated union \|
30	\| `Future[T]` \| Async value not yet available \| JavaScript `Promise` \|
31	\| `IO[T]` \| Lazy synchronous side effect \| Haskell's `IO` \|
32	\| `Task[T]` \| Lazy async computation \| fp-ts `Task` \|
33	\| `State[S, A]` \| Stateful computation \| Haskell's `State` monad \|
34
35	## Option[T] — Nullable Values Without nil
36
37	Represents a value that is either present (`Some`) or absent (`None`). Eliminates nil pointer risks at the type level.
38
39	```go
40	import "github.com/samber/mo"
41
42	name := mo.Some("Alice") // Option[string] with value
43	empty := mo.None[string]() // Option[string] without value
44	fromPtr := mo.PointerToOption(ptr) // nil pointer -> None
45
46	// Safe extraction
47	name.OrElse("Anonymous") // "Alice"
48	empty.OrElse("Anonymous") // "Anonymous"
49
50	// Transform if present, skip if absent
51	upper := name.Map(func(s string) (string, bool) {
52	return strings.ToUpper(s), true
53	})
54	```
55
56	Key methods: `Some`, `None`, `Get`, `MustGet`, `OrElse`, `OrEmpty`, `Map`, `FlatMap`, `Match`, `ForEach`, `ToPointer`, `IsPresent`, `IsAbsent`.
57
58	Option implements `json.Marshaler/Unmarshaler`, `sql.Scanner`, `driver.Valuer` — use it directly in JSON structs and database models.
59
60	For full API reference, see [Option Reference](./references/option.md).
61
62	## Result[T] — Error Handling as Values
63
64	Represents success (`Ok`) or failure (`Err`). Equivalent to `Either[error, T]` but specialized for Go's error pattern.
65
66	```go
67	// Wrap Go's (value, error) pattern
68	result := mo.TupleToResult(os.ReadFile("config.yaml"))
69
70	// Same-type transform — errors short-circuit automatically
71	upper := mo.Ok("hello").Map(func(s string) (string, error) {
72	return strings.ToUpper(s), nil
73	})
74	// Ok("HELLO")
75
76	// Extract with fallback
77	val := upper.OrElse("default")
78	```
79
80	Go limitation: Direct methods (`.Map`, `.FlatMap`) cannot change the type parameter — `Result[T].Map` returns `Result[T]`, not `Result[U]`. Go methods cannot introduce new type parameters. For type-changing transforms (e.g. `Result[[]byte]` to `Result[Config]`), use sub-package functions or `mo.Do`:
81
82	```go
83	import "github.com/samber/mo/result"
84
85	// Type-changing pipeline: []byte

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golang-samber-mo

33kinstalls179forks

View on GitHub

How to install golang-samber-mo?

samber/cc-skills-golang/golang-samber-mo

$npx -y skills add samber/cc-skills-golang --skill golang-samber-mo

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	Persona: You are a Go engineer bringing functional programming safety to Go. You use monads to make impossible states unrepresentable — nil checks become type constraints, error handling becomes composable pipelines.
2
3	Thinking mode: Use `ultrathink` when designing multi-step Option/Result/Either pipelines. Wrong type choice creates unnecessary wrapping/unwrapping that defeats the purpose of monads.
4
5	# samber/mo — Monads and Functional Abstractions for Go
6
7	Go 1.18+ library providing type-safe monadic types with zero dependencies. Inspired by Scala, Rust, and fp-ts.
8
9	Official Resources:
10
11	- [pkg.go.dev/github.com/samber/mo](https://pkg.go.dev/github.com/samber/mo)
12	- [github.com/samber/mo](https://github.com/samber/mo)
13
14	This skill is not exhaustive. Please refer to library documentation and code examples for more information. For Go package docs, symbols, versions, importers, and known vulnerabilities, → See `samber/cc-skills-golang@golang-pkg-go-dev` skill (`godig`) — prefer it over Context7 for Go package facts. To navigate this library's usage in your own code (definitions, call sites, diagnostics), → See `samber/cc-skills-golang@golang-gopls` skill (`gopls`). Context7 remains a fallback for docs not indexed on pkg.go.dev.
15
16	```bash
17	go get github.com/samber/mo
18	```
19
20	For an introduction to functional programming concepts and why monads are valuable in Go, see [Monads Guide](./references/monads-guide.md).
21
22	## Core Types at a Glance
23
24	\| Type \| Purpose \| Think of it as... \|
25	\| --- \| --- \| --- \|
26	\| `Option[T]` \| Value that may be absent \| Rust's `Option`, Java's `Optional` \|
27	\| `Result[T]` \| Operation that may fail \| Rust's `Result<T, E>`, replaces `(T, error)` \|
28	\| `Either[L, R]` \| Value of one of two types \| Scala's `Either`, TypeScript discriminated union \|
29	\| `EitherX[L, R]` \| Value of one of X types \| Scala's `Either`, TypeScript discriminated union \|
30	\| `Future[T]` \| Async value not yet available \| JavaScript `Promise` \|
31	\| `IO[T]` \| Lazy synchronous side effect \| Haskell's `IO` \|
32	\| `Task[T]` \| Lazy async computation \| fp-ts `Task` \|
33	\| `State[S, A]` \| Stateful computation \| Haskell's `State` monad \|
34
35	## Option[T] — Nullable Values Without nil
36
37	Represents a value that is either present (`Some`) or absent (`None`). Eliminates nil pointer risks at the type level.
38
39	```go
40	import "github.com/samber/mo"
41
42	name := mo.Some("Alice") // Option[string] with value
43	empty := mo.None[string]() // Option[string] without value
44	fromPtr := mo.PointerToOption(ptr) // nil pointer -> None
45
46	// Safe extraction
47	name.OrElse("Anonymous") // "Alice"
48	empty.OrElse("Anonymous") // "Anonymous"
49
50	// Transform if present, skip if absent
51	upper := name.Map(func(s string) (string, bool) {
52	return strings.ToUpper(s), true
53	})
54	```
55
56	Key methods: `Some`, `None`, `Get`, `MustGet`, `OrElse`, `OrEmpty`, `Map`, `FlatMap`, `Match`, `ForEach`, `ToPointer`, `IsPresent`, `IsAbsent`.
57
58	Option implements `json.Marshaler/Unmarshaler`, `sql.Scanner`, `driver.Valuer` — use it directly in JSON structs and database models.
59
60	For full API reference, see [Option Reference](./references/option.md).
61
62	## Result[T] — Error Handling as Values
63
64	Represents success (`Ok`) or failure (`Err`). Equivalent to `Either[error, T]` but specialized for Go's error pattern.
65
66	```go
67	// Wrap Go's (value, error) pattern
68	result := mo.TupleToResult(os.ReadFile("config.yaml"))
69
70	// Same-type transform — errors short-circuit automatically
71	upper := mo.Ok("hello").Map(func(s string) (string, error) {
72	return strings.ToUpper(s), nil
73	})
74	// Ok("HELLO")
75
76	// Extract with fallback
77	val := upper.OrElse("default")
78	```
79
80	Go limitation: Direct methods (`.Map`, `.FlatMap`) cannot change the type parameter — `Result[T].Map` returns `Result[T]`, not `Result[U]`. Go methods cannot introduce new type parameters. For type-changing transforms (e.g. `Result[[]byte]` to `Result[Config]`), use sub-package functions or `mo.Do`:
81
82	```go
83	import "github.com/samber/mo/result"
84
85	// Type-changing pipeline: []byte

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