goderive

goderive derives mundane golang functions that you do not want to maintain and keeps them up to date.

<a href="http://www.youtube.com/watch?feature=player_embedded&v=qFYByoGFIUE" target="_blank"> <img src="https://img.youtube.com/vi/qFYByoGFIUE/maxres2.jpg" alt="Watch the video" width="480" border="10" /> </a>

It does this by parsing your go code for functions, which are not implemented, and then generates these functions for you by deriving their implementations from the input parameter types.

Examples

In the following code the deriveEqual function will be spotted as a function that was not implemented (or was previously derived) and has a prefix deriveEqual.

package main

type MyStruct struct {
	Int64     int64
	StringPtr *string
}

func (this *MyStruct) Equal(that *MyStruct) bool {
	return deriveEqual(this, that)
}

goderive will then generate the following code in a derived.gen.go file in the same package:

func deriveEqual(this, that *MyStruct) bool {
	return (this == nil && that == nil) ||
		this != nil && that != nil &&
			this.Int64 == that.Int64 &&
			((this.StringPtr == nil && that.StringPtr == nil) ||
        (this.StringPtr != nil && that.StringPtr != nil && *(this.StringPtr) == *(that.StringPtr)))
}

Recursive Examples:

• Equal
• Compare
• DeepCopy
• GoString
• Hash

Set Examples:

• Keys
• Sort
• Unique
• Set
• Min
• Max
• Contains
• Intersect
• Union

Functional Examples:

• Compose
• Mem
• Traverse
• ToError

Concurrency Examples:

• Pipeline
• Do

Functions

Recursive Functions:

• Equal
  • deriveEqual(T, T) bool
  • deriveEqual(T) func(T) bool
• Compare
  • deriveCompare(T, T) int
  • deriveCompare(T) func(T) int
• DeepCopy
  • deriveDeepCopy(dst *T, src *T)
  • deriveDeepCopy(dst []T, src []T)
  • deriveDeepCopy(dst map[A]B, src map[A]B)
• Clone deriveClone(T) T
• GoString deriveGoString(T) string
• Hash deriveHash(T) uint64

Functional Functions:

• Fmap
  • deriveFmap(func(A) B, []A) []B
  • deriveFmap(func(rune) B, string) []B
  • deriveFmap(func(A) B, func() (A, error)) (B, error)
  • deriveFmap(func(A) (B, error), func() (A, error)) (func() (B, error), error)
  • deriveFmap(func(A), func() (A, error)) error
  • deriveFmap(func(A) (B, c, d, ...), func() (A, error)) (func() (B, c, d, ...), error)
• Join
  • deriveJoin([][]T) []T
  • deriveJoin([]string) string
  • deriveJoin(func() (T, error), error) func() (T, error)
  • deriveJoin(func() (T, ..., error), error) func() (T, ..., error)
• Flip deriveFlip(f func(A, B, ...) T) func(B, A, ...) T
• Curry deriveCurry(f func(A, B, ...) T) func(A) func(B, ...) T
• Uncurry deriveUncurry(f func(A) func(B, ...) T) func(A, B, ...) T
• Tuple deriveTuple(A, B, ...) func() (A, B, ...)
• Compose
  • deriveCompose(func() (A, error), func(A) (B, error)) func() (B, error)
  • deriveCompose(func(A) (B, error), func(B) (C, error)) func(A) (C, error)
  • deriveCompose(func(A...) (B..., error), func(B...) (C..., error)) func(A...) (C..., error)
  • deriveCompose(func(A...) (B..., error), ..., func(C...) (D..., error)) func(A...) (D..., error)
• Mem
  • deriveMem(func(A...) (B...)) func(A...) (B...)
• Traverse
  • deriveTraverse(func(A) (B, error), []A) ([]B, error)
• ToError
  • deriveToError(error, func(A...) (B..., bool)) func(A...) (B..., error)
  • deriveToError(error, func() bool) func() error
• Apply deriveApply(f func(...A, B) C, B) func(...A) C

Concurrency Functions:

• Fmap
  • deriveFmap(func(A) B, <-chan A) <-chan B
• Join
  • deriveJoin(<-chan <-chan T) <-chan T
  • deriveJoin(chan <-chan T) <-chan T
  • deriveJoin([]<-chan T) <-chan T
  • deriveJoin([]chan T) <-chan T
  • deriveJoin(chan T, chan T, ...) <-chan T
• Pipeline
  • derivePipeline(func(A) <-chan B, func(B) <-chan C) func(A) <-chan C
• Do
  • deriveDo(func() (A, error), func (B, error)) (A, B, error)
• Dup
  • deriveDup(c <-chan T) (c1, c2 <-chan T)

Deprecated in favour of generics:

• Keys deriveKeys(map[K]V) []K
• Sort deriveSort([]T) []T
• Unique deriveUnique([]T) []T
• Set deriveSet([]T) map[T]struct{}
• Min
  • deriveMin(list []T, default T) (min T)
  • deriveMin(T, T) T
• Max
  • deriveMax(list []T, default T) (max T)
  • deriveMax(T, T) T
• Contains deriveContains([]T, T) bool
• Intersect
  • deriveIntersect(a, b []T) []T
  • deriveIntersect(a, b map[T]struct{}) map[T]struct{}
• Union
  • deriveUnion(a, b []T) []T
  • deriveUnion(a, b map[T]struct{}) map[T]struct{}
• Filter deriveFilter(pred func(T) bool, []T) []T
• All deriveAll(pred func(T) bool, []T) bool
• Any deriveAny(pred func(T) bool, []T) bool
• TakeWhile deriveTakeWhile(pred func(T) bool, []T) []T

When goderive walks over your code it is looking for a function that:

• was not implemented (or was previously derived) and
• has a predefined prefix.

Functions which have been previously derived will be regenerated to keep them up to date with the latest modifications to your types. This keeps these functions, which are truly mundane to write, maintainable.

For example when someone in your team adds a new field to a struct and forgets to update the CopyTo method. This problem is solved by goderive, by generating generated functions given the new types.

Function prefixes are by default `deriveCamelCas