add examples for State[S, A]

README.md

@@ -141,18 +141,23 @@ Represent function func (S) (A, S), where S is state, A is result
 
 ### Create State
 ```go
-x := state.Return(int, string)(5)
-y := state.Put(int)(5)
+x := state.Return[any, int](5)
+y := state.Put(100)
+fmt.Println(x.RunState(nil)) // prints 5
+fmt.Println(y.RunState(6))   // prints 100
 ```
 
 ### Transform State into new value
 ```go
-func CountZeroes(numbs []int) int {
-    counter := state.Put(int)(0)
-    for _, x := range numbs {
-        state := state.bindI(int, Unit, int)(counter, state.Get(int)())
-        counter = state.FlatMap(int, int, int)(state, func(c int) { return state.Put(int)(c + 1) })
+func CountZeroes(ints []int) int {
+    counter := state.Put[int](0)
+    for _, x := range ints {
+        if x == 0 {
+            s := state.BindI[int, util.Unit, int](counter, state.Get[int]())
+            counter = state.FlatMap[int, int, util.Unit](s, func(c int) state.State[int, util.Unit] { return state.Put[int](c + 1) })
+        }
     }
-    return counter.RunState(0)
+    _, s := counter.RunState(0)
+    return s
 }
 ```

cmd/examples/state/state.go

@@ -0,0 +1,28 @@
+package main
+
+import (
+	"fmt"
+	"github.com/OlegStotsky/go-monads/state"
+	"github.com/OlegStotsky/go-monads/util"
+)
+
+func CountZeroes(ints []int) int {
+	counter := state.Put[int](0)
+	for _, x := range ints {
+		if x == 0 {
+			s := state.BindI[int, util.Unit, int](counter, state.Get[int]())
+			counter = state.FlatMap[int, int, util.Unit](s, func(c int) state.State[int, util.Unit] { return state.Put[int](c + 1) })
+		}
+	}
+	_, s := counter.RunState(0)
+	return s
+}
+
+func main() {
+	x := state.Return[any, int](5)
+	y := state.Put(100)
+	fmt.Println(x.RunState(nil)) // prints 5
+	fmt.Println(y.RunState(6))   // prints 100
+
+	fmt.Println(CountZeroes([]int{5, 4, 0, 0, 1, 0})) // prints 3
+}

state/state.go2 → state/state.go

@@ -51,7 +51,7 @@ func Put[S any](newState S) State[S, util.Unit] {
 }
 
 //Analogue of flatMap with ignoring value of base State
-func bindI[S, A, B any](s State[S, A], s2 State[S, B]) State[S, B] {
+func BindI[S, A, B any](s State[S, A], s2 State[S, B]) State[S, B] {
 	return stateImpl[S, B]{f: func(state S) (B, S) {
 		_, newState := s.RunState(state)
 		return s2.RunState(newState)