unicode: add function level examples

Change-Id: I9e968c03c6615a539b18701c84f830898242441d
Reviewed-on: https://go-review.googlesource.com/13926Reviewed-by: Russ Cox <rsc@golang.org>

src/unicode/example_test.go

+// Copyright 2015 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 unicode_test
+
+import (
+	"fmt"
+	"unicode"
+)
+
+// Functions starting with "Is" can be used to inspect which table of range a
+// rune belongs to. Note that runes may fit into more than one range.
+func Example_is() {
+
+	// constant with mixed type runes
+	const mixed = "\b5Ὂg̀9! ℃ᾭG"
+	for _, c := range mixed {
+		fmt.Printf("For %q:\n", c)
+		if unicode.IsControl(c) {
+			fmt.Println("\tis control rune")
+		}
+		if unicode.IsDigit(c) {
+			fmt.Println("\tis digit rune")
+		}
+		if unicode.IsGraphic(c) {
+			fmt.Println("\tis graphic rune")
+		}
+		if unicode.IsLetter(c) {
+			fmt.Println("\tis letter rune")
+		}
+		if unicode.IsLower(c) {
+			fmt.Println("\tis lower case rune")
+		}
+		if unicode.IsMark(c) {
+			fmt.Println("\tis mark rune")
+		}
+		if unicode.IsNumber(c) {
+			fmt.Println("\tis number rune")
+		}
+		if unicode.IsPrint(c) {
+			fmt.Println("\tis printable rune")
+		}
+		if !unicode.IsPrint(c) {
+			fmt.Println("\tis not printable rune")
+		}
+		if unicode.IsPunct(c) {
+			fmt.Println("\tis punct rune")
+		}
+		if unicode.IsSpace(c) {
+			fmt.Println("\tis space rune")
+		}
+		if unicode.IsSymbol(c) {
+			fmt.Println("\tis symbol rune")
+		}
+		if unicode.IsTitle(c) {
+			fmt.Println("\tis title case rune")
+		}
+		if unicode.IsUpper(c) {
+			fmt.Println("\tis upper case rune")
+		}
+	}
+
+	// Output:
+	// For '\b':
+	// 	is control rune
+	// 	is not printable rune
+	// For '5':
+	// 	is digit rune
+	// 	is graphic rune
+	// 	is number rune
+	// 	is printable rune
+	// For 'Ὂ':
+	// 	is graphic rune
+	// 	is letter rune
+	// 	is printable rune
+	// 	is upper case rune
+	// For 'g':
+	// 	is graphic rune
+	// 	is letter rune
+	// 	is lower case rune
+	// 	is printable rune
+	// For '̀':
+	// 	is graphic rune
+	// 	is mark rune
+	// 	is printable rune
+	// For '9':
+	// 	is digit rune
+	// 	is graphic rune
+	// 	is number rune
+	// 	is printable rune
+	// For '!':
+	// 	is graphic rune
+	// 	is printable rune
+	// 	is punct rune
+	// For ' ':
+	// 	is graphic rune
+	// 	is printable rune
+	// 	is space rune
+	// For '℃':
+	// 	is graphic rune
+	// 	is printable rune
+	// 	is symbol rune
+	// For 'ᾭ':
+	// 	is graphic rune
+	// 	is letter rune
+	// 	is printable rune
+	// 	is title case rune
+	// For 'G':
+	// 	is graphic rune
+	// 	is letter rune
+	// 	is printable rune
+	// 	is upper case rune
+}
+
+func ExampleSimpleFold() {
+	fmt.Printf("%#U\n", unicode.SimpleFold('A'))      // 'a'
+	fmt.Printf("%#U\n", unicode.SimpleFold('a'))      // 'A'
+	fmt.Printf("%#U\n", unicode.SimpleFold('K'))      // 'k'
+	fmt.Printf("%#U\n", unicode.SimpleFold('k'))      // '\u212A' (Kelvin symbol, K)
+	fmt.Printf("%#U\n", unicode.SimpleFold('\u212A')) // 'K'
+	fmt.Printf("%#U\n", unicode.SimpleFold('1'))      // '1'
+
+	// Output:
+	// U+0061 'a'
+	// U+0041 'A'
+	// U+006B 'k'
+	// U+212A 'K'
+	// U+004B 'K'
+	// U+0031 '1'
+}
+
+func ExampleTo() {
+	const lcG = 'g'
+	fmt.Printf("%#U\n", unicode.To(unicode.UpperCase, lcG))
+	fmt.Printf("%#U\n", unicode.To(unicode.LowerCase, lcG))
+	fmt.Printf("%#U\n", unicode.To(unicode.TitleCase, lcG))
+
+	const ucG = 'G'
+	fmt.Printf("%#U\n", unicode.To(unicode.UpperCase, ucG))
+	fmt.Printf("%#U\n", unicode.To(unicode.LowerCase, ucG))
+	fmt.Printf("%#U\n", unicode.To(unicode.TitleCase, ucG))
+
+	// Output:
+	// U+0047 'G'
+	// U+0067 'g'
+	// U+0047 'G'
+	// U+0047 'G'
+	// U+0067 'g'
+	// U+0047 'G'
+}
+
+func ExampleToLower() {
+	const ucG = 'G'
+	fmt.Printf("%#U\n", unicode.ToLower(ucG))
+
+	// Output:
+	// U+0067 'g'
+}
+func ExampleToTitle() {
+	const ucG = 'g'
+	fmt.Printf("%#U\n", unicode.ToTitle(ucG))
+
+	// Output:
+	// U+0047 'G'
+}
+
+func ExampleToUpper() {
+	const ucG = 'g'
+	fmt.Printf("%#U\n", unicode.ToUpper(ucG))
+
+	// Output:
+	// U+0047 'G'
+}
+
+func ExampleSpecialCase() {
+	t := unicode.TurkishCase
+
+	const lci = 'i'
+	fmt.Printf("%#U\n", t.ToLower(lci))
+	fmt.Printf("%#U\n", t.ToTitle(lci))
+	fmt.Printf("%#U\n", t.ToUpper(lci))
+
+	const uci = 'İ'
+	fmt.Printf("%#U\n", t.ToLower(uci))
+	fmt.Printf("%#U\n", t.ToTitle(uci))
+	fmt.Printf("%#U\n", t.ToUpper(uci))
+
+	// Output:
+	// U+0069 'i'
+	// U+0130 'İ'
+	// U+0130 'İ'
+	// U+0069 'i'
+	// U+0130 'İ'
+	// U+0130 'İ'
+}