all: use latest type set grammar and 1.18

Author: changkun

README.md

@@ -1,6 +1,6 @@
 # go2generics [![PkgGoDev](https://pkg.go.dev/badge/golang.design/x/go2generics)](https://pkg.go.dev/golang.design/x/go2generics) ![](https://changkun.de/urlstat?mode=github&repo=golang-design/go2generics)
 
-A chunk of demos and research regarding Go 2 generics (type parameters).
+A chunk of demos and research regarding Go 2 generics (type parameters and type sets).
 
 ## Getting started
 
@@ -16,10 +16,55 @@ You can use the latest Go tip version to build all code examples in this reposit
 ```sh
 $ git clone https://github.com/golang/go && cd src && ./all.bash
 
-$ ../bin/go test -gcflags=all=-G=3 -v ./...
+$ ../bin/go test -v ./...
 ```
 
-The `-gcflags=all=-G=3` is the key compiler flag to run Go code with type parameters.
+## Working Examples
+
+The current compiler implementation is still under development. 
+These examples can be run without an error:
+
+```
+gotip run demo/ex1-sort.go
+gotip run demo/ex2-mapreduce.go
+gotip run demo/ex3-stack.go
+gotip run demo/ex4-map.go
+cd errors && gotip test
+cd fmt    && gotip test
+cd future && gotip test
+cd linalg && gotip test
+cd list   && gotip test
+cd math   && gotip test
+cd metrics&& gotip test
+cd ring   && gotip test
+cd stack  && gotip test
+cd strings&& gotip test
+cd sync/atomic && gotip test
+cd tree   && gotip test
+```
+
+## Upcoming Standard Package
+
+See [changkun/generics](https://github.com/changkun/generics).
+
+## Known Issues
+
+The know issues of the current implementation:
+
+- Type parameter for slices is not supported yet.
+- Package import is still buggy
+
+These written packages are not runnable yet (will trigger some internal compiler bug):
+
+```
+chans
+demo/ex5-loadbalance.go
+graph
+maps
+sched
+slices
+sync
+```
 
 ## Licnese
 

chans/lb_test.go

@@ -46,7 +46,5 @@ func TestLB(t *testing.T) {
 	for i := 0; i < 10; i++ {
 		outs[i] = make(chan int, 10)
 	}
-	LB(func(m int) int {
-		return rand.Intn(m)
-	}, ins, outs)
+	LB(func(m int) int { return rand.Intn(m)}, ins, outs)
 }

constraints/string.go

@@ -15,5 +15,5 @@ type PrintableStringer[T Stringer] interface {
 }
 
 type Sequence interface {
-	type string, []byte
+	~string | ~[]byte
 }

constraints/types.go

@@ -9,29 +9,29 @@ package constraints
 // In practice this type constraint would likely be defined in
 // a standard library package.
 type Ordered interface {
-	type int, int8, int16, int32, int64,
-		uint, uint8, uint16, uint32, uint64, uintptr,
-		float32, float64,
-		string
+	~int | ~int8 | ~int16 | ~int32 | ~int64 |
+	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
+	~float32 | ~float64 |
+	~string
 }
 
 type Integer interface {
-	type int8, int16, int32, int64, int,
-		uint8, uint16, uint32, uint64, uint
+	~int8 | ~int16 | ~int32 | ~int64 | ~int |
+	~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uint
 }
 
 type Signed interface {
-	type int, int8, int16, int32, int64
+	~int | ~int8 | ~int16 | ~int32 | ~int64
 }
 
 type Unsigned interface {
-	type uint, uint8, uint16, uint32, uint64, uintptr
+	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr
 }
 
 type Adder[T any] interface {
 	Add(T) T
 }
 
 type FloatComplex interface {
-	type float32, float64, complex64, complex128
+	~float32 | ~float64 | ~complex64 | ~complex128
 }

go.mod

@@ -1,3 +1,3 @@
 module golang.design/x/go2generics
 
-go 1.16
+go 1.18

history/202108.go2.txt

@@ -0,0 +1,40 @@
+// Copyright 2021 Changkun Ou. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package history
+
+// constrained type set
+
+type Ordered interface {
+	~int | ~int8 | ~int16 | ~int32 | ~int64 |
+	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
+	~float32 | ~float64 | ~string
+}
+
+// Max returns the maximum among all parameters
+func Max[T Ordered](v0 T, vn ...T) T {
+	switch l := len(vn); {
+	case l == 0:
+		return v0
+	case l == 1:
+		if v0 > vn[0] { return v0 }
+		return vn[0]
+	default:
+		vv := Max(vn[0], vn[1:]...)
+		if v0 > vv { return v0 }
+		return vv
+	}
+}
+
+// a more complex example:
+
+type I1 [P1 any] interface {
+    m1(x P1)
+}
+type I2 [P1, P2 any] interface {
+    m2(x P1) P2
+    type int, float64
+}
+
+func F[P1 I1[P1], P2 I2[P1, P2]] (x P1, y P2) {}

linalg/linalg.go

@@ -9,9 +9,9 @@ import "math"
 // Numeric is a contract that matches any numeric type.
 // It would likely be in a contracts package in the standard library.
 type Numeric interface {
-	type int, int8, int16, int32, int64, uint, uint8,
-		uint16, uint32, uint64, uintptr, float32,
-		float64, complex64, complex128
+	~int | ~int8 | ~int16 | ~int32 | ~int64 | ~uint | ~uint8 |
+	~uint16 | ~uint32 | ~uint64 | ~uintptr | ~float32 |
+	~float64 | ~complex64 | ~complex128
 }
 
 // NumericAbs matches numeric types with an Abs method.
@@ -22,13 +22,13 @@ type NumericAbs[T any] interface {
 
 // OrderedNumeric matches numeric types that support the < operator.
 type OrderedNumeric interface {
-	type int, int8, int16, int32, int64, uint, uint8,
-		uint16, uint32, uint64, uintptr, float32, float64
+	~int | ~int8 | ~int16 | ~int32 | ~int64 | ~uint | ~uint8 |
+	~uint16 | ~uint32 | ~uint64 | ~uintptr | ~float32 | ~float64
 }
 
 // Complex matches the two complex types, which do not have a < operator.
 type Complex interface {
-	type complex64, complex128
+	~complex64 | ~complex128
 }
 
 func DotProduct[T Numeric](s1, s2 []T) T {
@@ -44,7 +44,7 @@ func DotProduct[T Numeric](s1, s2 []T) T {
 
 // AbsDifference computes the absolute value of the difference of
 // a and b, where the absolute value is determined by the Abs method.
-func AbsDifference[T NumericAbs](a, b T) T {
+func AbsDifference[T NumericAbs[T]](a, b T) T {
 	d := a - b
 	return d.Abs()
 }

linalg/linalg_test.go

@@ -0,0 +1,17 @@
+// Copyright 2021 Changkun Ou. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package linalg
+
+import "testing"
+
+func TestDotProduct(t *testing.T) {
+	a := []int{1, 2, 3}
+	b := []int{2, 3, 4}
+
+	val := DotProduct(a, b)
+	if val != 20 {
+		t.Fatalf("unexpected DotProduct result, got %v want %v", val, 20)
+	}
+}

list/list_test.go

@@ -0,0 +1,15 @@
+// Copyright 2021 Changkun Ou. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package list
+
+import "testing"
+
+func TestList(t *testing.T) {
+	l := List[int]{}
+
+	l.Push(1)
+	l.Push(2)
+	l.Push(3)
+}

maps/orderedmap.go

@@ -70,7 +70,7 @@ type keyValue[K, V any] struct {
 
 // InOrder returns an iterator that does an in-order traversal of the map.
 func (m *OrderedMap[K, V]) InOrder() *Iterator[K, V] {
-	sender, receiver := chans.Ranger(keyValue[K, V])()
+	sender, receiver := chans.Ranger[keyValue[K, V]]()
 	var f func(*node[K, V]) bool
 	f = func(n *node[K, V]) bool {
 		if n == nil {