initial checkin

Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>

number/magma.go

@@ -0,0 +1,11 @@
+package number
+
+import (
+	M "github.com/ibm/fp-go/magma"
+)
+
+func MagmaSub[A int | int8 | int16 | int32 | int64 | float32 | float64 | complex64 | complex128]() M.Magma[A] {
+	return M.MakeMagma(func(first A, second A) A {
+		return first - second
+	})
+}

number/magma_test.go

@@ -0,0 +1,18 @@
+package number
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	M "github.com/ibm/fp-go/magma"
+)
+
+func TestSemigroupIsMagma(t *testing.T) {
+	sum := SemigroupSum[int]()
+
+	var magma M.Magma[int] = sum
+
+	assert.Equal(t, sum.Concat(1, 2), magma.Concat(1, 2))
+	assert.Equal(t, sum.Concat(1, 2), sum.Concat(2, 1))
+}

number/monoid.go

@@ -0,0 +1,13 @@
+package number
+
+import (
+	M "github.com/ibm/fp-go/monoid"
+)
+
+func MonoidSum[A int | int8 | int16 | int32 | int64 | float32 | float64 | complex64 | complex128]() M.Monoid[A] {
+	s := SemigroupSum[A]()
+	return M.MakeMonoid(
+		s.Concat,
+		0,
+	)
+}

number/monoid_test.go

@@ -0,0 +1,11 @@
+package number
+
+import (
+	"testing"
+
+	M "github.com/ibm/fp-go/monoid/testing"
+)
+
+func TestMonoidSum(t *testing.T) {
+	M.AssertLaws(t, MonoidSum[int]())([]int{0, 1, 1000, -1})
+}

number/semigroup.go

@@ -0,0 +1,11 @@
+package number
+
+import (
+	S "github.com/ibm/fp-go/semigroup"
+)
+
+func SemigroupSum[A int | int8 | int16 | int32 | int64 | float32 | float64 | complex64 | complex128]() S.Semigroup[A] {
+	return S.MakeSemigroup(func(first A, second A) A {
+		return first + second
+	})
+}