Remove exp/exception as it's no longer relevant

R=gri, adg
CC=golang-dev, r, rsc
https://golang.org/cl/857048

src/pkg/Makefile

@@ -67,7 +67,6 @@ DIRS=\
 	exp/datafmt\
 	exp/draw\
 	exp/eval\
-	exp/exception\
 	exp/iterable\
 	expvar\
 	flag\

src/pkg/exp/exception/Makefile

-# Copyright 2009 The Go Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style
-# license that can be found in the LICENSE file.
-
-include ../../../Make.$(GOARCH)
-
-TARG=exp/exception
-GOFILES=\
-	exception.go\
-
-include ../../../Make.pkg

src/pkg/exp/exception/exception.go

-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This package illustrates how basic try-catch exception handling
-// can be emulated using goroutines, channels, and closures.
-//
-// This package is *not* intended as a general exception handler
-// library.
-//
-package exception
-
-import (
-	"fmt"
-	"runtime"
-)
-
-// A Handler function handles an arbitrary exception value x.
-type Handler func(x interface{})
-
-// An Exception carries an exception value.
-type Exception struct {
-	Value interface{} // Value may be the nil exception
-}
-
-// Try invokes a function f with a Handler to throw exceptions.
-// The function f may terminate abnormally with an arbitrary
-// exception x by calling throw(x) within f. If an exception is
-// thrown, Try returns an *Exception; otherwise it returns nil.
-//
-// Usage pattern:
-//
-//	if x := exception.Try(func(throw exception.Handler) {
-//		...
-//		throw(42);  // terminate f by throwing exception 42
-//		...
-//	}); x != nil {
-//		// catch exception, e.g. print it
-//		fmt.Println(x.Value);
-//	}
-//
-// Alternative:
-//
-//	exception.Try(func(throw exception.Handler) {
-//		...
-//		throw(42);  // terminate f by throwing exception 42
-//		...
-//	}).Catch(func (x interface{}) {
-//		// catch exception, e.g. print it
-//		fmt.Println(x);
-//	})
-//
-func Try(f func(throw Handler)) *Exception {
-	h := make(chan *Exception)
-
-	// execute try block
-	go func() {
-		f(func(x interface{}) {
-			h <- &Exception{x}
-			runtime.Goexit()
-		})
-		h <- nil // clean termination
-	}()
-
-	return <-h
-}
-
-
-// If x != nil, Catch invokes f with the exception value x.Value.
-// See Try for usage patterns.
-func (x *Exception) Catch(f Handler) {
-	if x != nil {
-		f(x.Value)
-	}
-}
-
-
-func (x *Exception) String() string {
-	if x != nil {
-		return fmt.Sprintf("exception: %v", x.Value)
-	}
-	return ""
-}

src/pkg/exp/exception/exception_test.go

-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package exception
-
-import "testing"
-
-func TestNoException(t *testing.T) {
-	e := Try(func(throw Handler) {})
-	if e != nil {
-		t.Fatalf("no exception expected, found: %v", e)
-	}
-}
-
-
-func TestNilException(t *testing.T) {
-	e := Try(func(throw Handler) { throw(nil) })
-	if e == nil {
-		t.Fatalf("exception expected", e)
-	}
-	if e.Value != nil {
-		t.Fatalf("nil exception expected, found: %v", e)
-	}
-}
-
-
-func TestTry(t *testing.T) {
-	s := 0
-	for i := 1; i <= 10; i++ {
-		e := Try(func(throw Handler) {
-			if i%3 == 0 {
-				throw(i)
-				panic("throw returned")
-			}
-		})
-		if e != nil {
-			s += e.Value.(int)
-		}
-	}
-	result := 3 + 6 + 9
-	if s != result {
-		t.Fatalf("expected: %d, found: %d", result, s)
-	}
-}
-
-
-func TestCatch(t *testing.T) {
-	s := 0
-	for i := 1; i <= 10; i++ {
-		Try(func(throw Handler) {
-			if i%3 == 0 {
-				throw(i)
-			}
-		}).Catch(func(x interface{}) { s += x.(int) })
-	}
-	result := 3 + 6 + 9
-	if s != result {
-		t.Fatalf("expected: %d, found: %d", result, s)
-	}
-}