1 files changed, 120 insertions, 0 deletions
diff --git a/doc/progs/error.go b/doc/progs/error.go
new file mode 100644
index 000000000..ffa7ec1cc
--- /dev/null
+++ b/doc/progs/error.go
@@ -0,0 +1,120 @@
+// Copyright 2011 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 file contains the code snippets included in "Error Handling and Go."
+
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"time"
+)
+
+type File struct{}
+
+func Open(name string) (file *File, err error)
+
+func openFile() { // OMIT
+	f, err := os.Open("filename.ext")
+	if err != nil {
+		log.Fatal(err)
+	}
+	// do something with the open *File f
+	// STOP OMIT
+	_ = f
+}
+
+// errorString is a trivial implementation of error.
+type errorString struct {
+	s string
+}
+
+func (e *errorString) Error() string {
+	return e.s
+}
+
+// STOP OMIT
+
+// New returns an error that formats as the given text.
+func New(text string) error {
+	return &errorString{text}
+}
+
+// STOP OMIT
+
+func Sqrt(f float64) (float64, error) {
+	if f < 0 {
+		return 0, errors.New("math: square root of negative number")
+	}
+	// implementation
+	return 0, nil // OMIT
+}
+
+// STOP OMIT
+
+func printErr() (int, error) { // OMIT
+	f, err := Sqrt(-1)
+	if err != nil {
+		fmt.Println(err)
+	}
+	// STOP OMIT
+	// fmtError OMIT
+	if f < 0 {
+		return 0, fmt.Errorf("math: square root of negative number %g", f)
+	}
+	// STOP OMIT
+	return 0, nil
+}
+
+type NegativeSqrtError float64
+
+func (f NegativeSqrtError) Error() string {
+	return fmt.Sprintf("math: square root of negative number %g", float64(f))
+}
+
+// STOP OMIT
+
+type SyntaxError struct {
+	msg    string // description of error
+	Offset int64  // error occurred after reading Offset bytes
+}
+
+func (e *SyntaxError) Error() string { return e.msg }
+
+// STOP OMIT
+
+func decodeError(dec *json.Decoder, val struct{}) error { // OMIT
+	var f os.FileInfo // OMIT
+	if err := dec.Decode(&val); err != nil {
+		if serr, ok := err.(*json.SyntaxError); ok {
+			line, col := findLine(f, serr.Offset)
+			return fmt.Errorf("%s:%d:%d: %v", f.Name(), line, col, err)
+		}
+		return err
+	}
+	// STOP OMIT
+	return nil
+}
+
+func findLine(os.FileInfo, int64) (int, int)
+
+func netError(err error) { // OMIT
+	for { // OMIT
+		if nerr, ok := err.(net.Error); ok && nerr.Temporary() {
+			time.Sleep(1e9)
+			continue
+		}
+		if err != nil {
+			log.Fatal(err)
+		}
+		// STOP OMIT
+	}
+}
+
+func main() {}