Generalized Golang Slice trick with reflect

Are you ready to exchange runtime speed with ease of coding?

Examples

import slice
...
  names := []string{"john", "ann", "diana", "sam", "anderson"}
  names = slice.Append(names, []string{"song", "choi"}).([]string)
  // or
  names = slice.AppendStr(names, []string{"song", "choi"})

type car struct {
  name string
  value int
}
...
	cars := []car{{"cadillac", 30}, {"jeep", 20}, {"sports", 100}}
	mycar_, cars_ := slice.Pop(cars)
	mycar := mycar_.(car)
	cars = cars_.([]car)
  // or
  mycar, cars := PopCar(cars)
  // but it needs regeneration with your custom struct definition in `slicetrick_generate.go` and `generate.go`

var In = slice.In
...
  numbers := []int {1, 35, 23, 29, 3, 7, 15}
  amILucky := In(numbers, 7)
  // or
  amILucky := slice.T{7}.In(numbers)

Result of benchmark as usage

• Usually, switch-case style is a bit slower.
• You can mock-up your program faster with reflection version of function.
• When it's ready to ship your program, you can switch to type specified version of functions.
• You can optimize further with custom list of precompiled types.

How to change precompiled types list and regenerate

• Open generate.go and edit type list (line number 2). Below is default value specifying all of the go value types.

//go:generate ./template -d bool int int8 int16 int32 int64 uint uint8 uint16 uint32 uint64 uintptr float32 float64 complex64 complex128 string

• Type go generate to generate and build.

Benchmark result

with all default types precompiled ( default setting of generate.go )

	switch-case		reflection
Function Name	String Specified (ex:AppendStr())	Reflection (ex:Append())	String	Reflection
Append	244 ns/op	625 ns/op	248 ns/op	600 ns/op
Copy	182 ns/op	626 ns/op	174 ns/op	632 ns/op
Cut	134 ns/op	532 ns/op	92.9 ns/op	473 ns/op
Delete	105 ns/op	512 ns/op	106 ns/op	477 ns/op
DeleteWithoutPreservingOrder	81.6 ns/op	262 ns/op	80.3 ns/op	288 ns/op
Expand	403 ns/op	1184 ns/op	471 ns/op	1291 ns/op
Extend	281 ns/op	674 ns/op	286 ns/op	689 ns/op
Insert	295 ns/op	1310 ns/op	297 ns/op	1252 ns/op
InsertVector	303 ns/op	1318 ns/op	326 ns/op	1321 ns/op
Pop	84.2 ns/op	307 ns/op	91.0 ns/op	340 ns/op
PopBack	79.4 ns/op	311 ns/op	92.8 ns/op	314 ns/op
Push	185 ns/op	487 ns/op	196 ns/op	500 ns/op
PushBack	241 ns/op	642 ns/op	255 ns/op	656 ns/op
Shift	83.2 ns/op	322 ns/op	83.4 ns/op	316 ns/op
Unshift	264 ns/op	673 ns/op	250 ns/op	707 ns/op
FilterWithoutAlloc	289 ns/op	2253 ns/op	275 ns/op	2118 ns/op
Reverse	140 ns/op	414 ns/op	130 ns/op	389 ns/op

with string only precompiled

	switch-case		reflection
Function Name	String Specified (ex:AppendStr())	Reflection (ex:Append())	String	Reflection
Append	246 ns/op	597 ns/op	249 ns/op	620 ns/op
Copy	179 ns/op	575 ns/op	198 ns/op	550 ns/op
Cut	109 ns/op	540 ns/op	92.2 ns/op	467 ns/op
Delete	104 ns/op	524 ns/op	90.3 ns/op	462 ns/op
DeleteWithoutPreservingOrder	87.9 ns/op	268 ns/op	80.0 ns/op	261 ns/op
Expand	416 ns/op	1199 ns/op	396 ns/op	1186 ns/op
Extend	323 ns/op	715 ns/op	277 ns/op	673 ns/op
Insert	311 ns/op	1310 ns/op	318 ns/op	1407 ns/op
InsertVector	315 ns/op	1273 ns/op	319 ns/op	1253 ns/op
Pop	84.3 ns/op	323 ns/op	85.8 ns/op	298 ns/op
PopBack	83.3 ns/op	320 ns/op	80.5 ns/op	306 ns/op
Push	190 ns/op	519 ns/op	184 ns/op	563 ns/op
PushBack	250 ns/op	674 ns/op	264 ns/op	682 ns/op
Shift	85.2 ns/op	319 ns/op	82.4 ns/op	331 ns/op
Unshift	249 ns/op	649 ns/op	248 ns/op	630 ns/op
FilterWithoutAlloc	270 ns/op	2038 ns/op	277 ns/op	2026 ns/op
Reverse	138 ns/op	427 ns/op	136 ns/op	380 ns/op