slices: change ReduceWith to ReduceFrom and add comments

Author: Sypheos

go.mod

@@ -33,6 +33,7 @@ require (
 	github.com/upfluence/log v0.0.5
 	github.com/upfluence/stats v0.1.4
 	github.com/upfluence/thrift v2.4.4+incompatible
+	golang.org/x/exp v0.0.0-20240909161429-701f63a606c0
 	golang.org/x/oauth2 v0.19.0
 	golang.org/x/sync v0.8.0
 	golang.org/x/term v0.13.0
@@ -57,7 +58,6 @@ require (
 	go.uber.org/atomic v1.6.0 // indirect
 	go.uber.org/multierr v1.5.0 // indirect
 	golang.org/x/crypto v0.14.0 // indirect
-	golang.org/x/exp v0.0.0-20240909161429-701f63a606c0 // indirect
 	golang.org/x/sys v0.13.0 // indirect
 	google.golang.org/protobuf v1.31.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect

go.sum

@@ -178,8 +178,8 @@ github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
-github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/go-querystring v1.0.0/go.mod h1:odCYkC5MyYFN7vkCjXpyrEuKhc/BUO6wN/zVPAxq5ck=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
 github.com/google/renameio v0.1.0/go.mod h1:KWCgfxg9yswjAJkECMjeO8J8rahYeXnNhOm40UhjYkI=
@@ -560,8 +560,7 @@ golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.4.0 h1:zxkM55ReGkDlKSM+Fu41A+zmbZuaPVbGMzvvdUPznYQ=
-golang.org/x/sync v0.4.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
 golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20180823144017-11551d06cbcc/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
@@ -618,9 +617,8 @@ golang.org/x/tools v0.0.0-20190621195816-6e04913cbbac/go.mod h1:/rFqwRUd4F7ZHNgw
 golang.org/x/tools v0.0.0-20191029041327-9cc4af7d6b2c/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20191029190741-b9c20aec41a5/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.0.0-20200103221440-774c71fcf114/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
-golang.org/x/tools v0.6.0 h1:BOw41kyTf3PuCW1pVQf8+Cyg8pMlkYB1oo9iJ6D/lKM=
-golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
 golang.org/x/tools v0.25.0 h1:oFU9pkj/iJgs+0DT+VMHrx+oBKs/LJMV+Uvg78sl+fE=
+golang.org/x/tools v0.25.0/go.mod h1:/vtpO8WL1N9cQC3FN5zPqb//fRXskFHbLKk4OW1Q7rg=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

slices/reduce.go

@@ -2,18 +2,23 @@ package slices
 
 import "golang.org/x/exp/constraints"
 
-func ReduceWith[S ~[]E, E any, A any](s S, acc A, fn func(A, E) A) A {
-	for _, e := range s {
-		acc = fn(acc, e)
+// ReduceFrom will iterate over each element of slice and call reduceFn for each.
+// The return value of each reduceFn is passed to the next call of reduceFn as acc, or
+// in other term at each iteration on the slice.
+func ReduceFrom[S ~[]E, E any, A any](slice S, acc A, reduceFn func(acc A, elem E) A) A {
+	for _, e := range slice {
+		acc = reduceFn(acc, e)
 	}
 
 	return acc
 }
 
-func Reduce[S ~[]E, E any, A any](s S, fn func(A, E) A) A {
+// Reduce does the same as ReduceFrom but use the zero value of A as
+// the first value to be passed to reduceFn.
+func Reduce[S ~[]E, E any, A any](slice S, reduceFn func(acc A, elem E) A) A {
 	var acc A
 
-	return ReduceWith(s, acc, fn)
+	return ReduceFrom(slice, acc, reduceFn)
 }
 
 type sumable interface {

slices/reduce_test.go

@@ -19,7 +19,7 @@ func TestReduceWith(t *testing.T) {
 		{slice: []int{1}, acc: 0, fn: func(a, b int) int { return a + b }, want: 1},
 	} {
 		t.Run("", func(t *testing.T) {
-			got := ReduceWith(tt.slice, tt.acc, tt.fn)
+			got := ReduceFrom(tt.slice, tt.acc, tt.fn)
 			assert.Equal(t, tt.want, got)
 		})
 	}
@@ -43,15 +43,15 @@ func TestReduce(t *testing.T) {
 
 func TestSum(t *testing.T) {
 	t.Run("integer", func(t *testing.T) {
-		assert.Equal(t, Reduce([]int{1, 2}, Sum), 3)
-		assert.Equal(t, ReduceWith([]int{1, 2}, 22, Sum), 25)
+		assert.Equal(t, 3, Reduce([]int{1, 2}, Sum))
+		assert.Equal(t, 25, ReduceFrom([]int{1, 2}, 22, Sum))
 	})
 	t.Run("float", func(t *testing.T) {
-		assert.Equal(t, Reduce([]float64{1.1, 2.3}, Sum), 3.4)
-		assert.Equal(t, ReduceWith([]float64{1.1, 2.2}, 22.22, Sum), 25.52)
+		assert.Equal(t, 3.4, Reduce([]float64{1.1, 2.3}, Sum))
+		assert.Equal(t, 25.52, ReduceFrom([]float64{1.1, 2.2}, 22.22, Sum))
 	})
 	t.Run("string", func(t *testing.T) {
-		assert.Equal(t, Reduce([]string{"foo", "bar"}, Sum), "foobar")
-		assert.Equal(t, ReduceWith([]string{"foo", "bar"}, "buz", Sum), "buzfoobar")
+		assert.Equal(t, "foobar", Reduce([]string{"foo", "bar"}, Sum))
+		assert.Equal(t, "buzfoobar", ReduceFrom([]string{"foo", "bar"}, "buz", Sum))
 	})
 }