golang example_test 代码
文件路径：/src/text/scanner/example_test.go
/ Copyright 2018 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 scanner_test
import (
"fmt"
"strings"
"text/scanner"
"unicode"
)
func Example() {
const src = `
/ This is scanned code.
if a > 10 {
someParsable = text
}`
var s scanner.Scanner
s.Init(strings.NewReader(src))
s.Filename = "example"
for tok := s.Scan(); tok != scanner.EOF; tok = s.Scan() {
fmt.Printf("%s: %s\n", s.Position, s.TokenText())
}
/ Output:
/ example:3:1: if
/ example:3:4: a
/ example:3:6: >
/ example:3:8: 10
/ example:3:11: {
/ example:4:2: someParsable
/ example:4:15: =
/ example:4:17: text
/ example:5:1: }
}
func Example_isIdentRune() {
const src = "%var1 var2%"
var s scanner.Scanner
s.Init(strings.NewReader(src))
s.Filename = "default"
for tok := s.Scan(); tok != scanner.EOF; tok = s.Scan() {
fmt.Printf("%s: %s\n", s.Position, s.TokenText())
}
fmt.Println()
s.Init(strings.NewReader(src))
s.Filename = "percent"
/ treat leading '%' as part of an identifier
s.IsIdentRune = func(ch rune, i int) bool {
return ch == '%' && i == 0 || unicode.IsLetter(ch) || unicode.IsDigit(ch) && i > 0
}
for tok := s.Scan(); tok != scanner.EOF; tok = s.Scan() {
fmt.Printf("%s: %s\n", s.Position, s.TokenText())
}
/ Output:
/ default:1:1: %
/ default:1:2: var1
/ default:1:7: var2
/ default:1:11: %
/
/ percent:1:1: %var1
/ percent:1:7: var2
/ percent:1:11: %
}
func Example_mode() {
const src = `
/ Comment begins at column 5.
This line should not be included in the output.
/*
This multiline comment
should be extracted in
its entirety.
*/
`
var s scanner.Scanner
s.Init(strings.NewReader(src))
s.Filename = "comments"
s.Mode ^= scanner.SkipComments / don't skip comments
for tok := s.Scan(); tok != scanner.EOF; tok = s.Scan() {
txt := s.TokenText()
if strings.HasPrefix(txt, "/") || strings.HasPrefix(txt, "/*") {
fmt.Printf("%s: %s\n", s.Position, txt)
}
}
/ Output:
/ comments:2:5: / Comment begins at column 5.
/ comments:6:1: /*
/ This multiline comment
/ should be extracted in
/ its entirety.
/ */
}
func Example_whitespace() {
/ tab-separated values
const src = `aa ab ac ad
ba bb bc bd
ca cb cc cd
da db dc dd`
var (
col, row int
s scanner.Scanner
tsv [4][4]string / large enough for example above
)
s.Init(strings.NewReader(src))
s.Whitespace ^= 1<<'\t' | 1<<'\n' / don't skip tabs and new lines
for tok := s.Scan(); tok != scanner.EOF; tok = s.Scan() {
switch tok {
case '\n':
row++
col = 0
case '\t':
col++
default:
tsv[row][col] = s.TokenText()
}
}
fmt.Print(tsv)
/ Output:
/ [[aa ab ac ad] [ba bb bc bd] [ca cb cc cd] [da db dc dd]]
}