Imported Upstream version 1.4upstream/1.4

1 files changed, 82 insertions, 0 deletions

diff --git a/src/bufio/example_test.go b/src/bufio/example_test.go
new file mode 100644
index 000000000..3da914142
--- /dev/null
+++ b/src/bufio/example_test.go
@@ -0,0 +1,82 @@
+// Copyright 2013 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 bufio_test
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func ExampleWriter() {
+	w := bufio.NewWriter(os.Stdout)
+	fmt.Fprint(w, "Hello, ")
+	fmt.Fprint(w, "world!")
+	w.Flush() // Don't forget to flush!
+	// Output: Hello, world!
+}
+
+// The simplest use of a Scanner, to read standard input as a set of lines.
+func ExampleScanner_lines() {
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		fmt.Println(scanner.Text()) // Println will add back the final '\n'
+	}
+	if err := scanner.Err(); err != nil {
+		fmt.Fprintln(os.Stderr, "reading standard input:", err)
+	}
+}
+
+// Use a Scanner to implement a simple word-count utility by scanning the
+// input as a sequence of space-delimited tokens.
+func ExampleScanner_words() {
+	// An artificial input source.
+	const input = "Now is the winter of our discontent,\nMade glorious summer by this sun of York.\n"
+	scanner := bufio.NewScanner(strings.NewReader(input))
+	// Set the split function for the scanning operation.
+	scanner.Split(bufio.ScanWords)
+	// Count the words.
+	count := 0
+	for scanner.Scan() {
+		count++
+	}
+	if err := scanner.Err(); err != nil {
+		fmt.Fprintln(os.Stderr, "reading input:", err)
+	}
+	fmt.Printf("%d\n", count)
+	// Output: 15
+}
+
+// Use a Scanner with a custom split function (built by wrapping ScanWords) to validate
+// 32-bit decimal input.
+func ExampleScanner_custom() {
+	// An artificial input source.
+	const input = "1234 5678 1234567901234567890"
+	scanner := bufio.NewScanner(strings.NewReader(input))
+	// Create a custom split function by wrapping the existing ScanWords function.
+	split := func(data []byte, atEOF bool) (advance int, token []byte, err error) {
+		advance, token, err = bufio.ScanWords(data, atEOF)
+		if err == nil && token != nil {
+			_, err = strconv.ParseInt(string(token), 10, 32)
+		}
+		return
+	}
+	// Set the split function for the scanning operation.
+	scanner.Split(split)
+	// Validate the input
+	for scanner.Scan() {
+		fmt.Printf("%s\n", scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		fmt.Printf("Invalid input: %s", err)
+	}
+	// Output:
+	// 1234
+	// 5678
+	// Invalid input: strconv.ParseInt: parsing "1234567901234567890": value out of range
+}