~mna/runes

ref: c0544805d67029ade996e60e893618ae4aac7464 runes/main.go -rw-r--r-- 3.6 KiB
c0544805Martin Angers fix help text 1 year, 3 months ago
                                                                                
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
// Command runes prints Unicode runes to stdout along with UTF8
// encoding information. Specific code points and ranges of code
// points can be provided as arguments.
package main

import (
	"flag"
	"fmt"
	"os"
	"strconv"
	"strings"
	"unicode"
	"unicode/utf8"
)

func main() {
	var (
		flagHelp  = flag.Bool("h", false, "Display this message.")
		flagLHelp = flag.Bool("help", false, "Display this message.")
		flagJSON  = flag.Bool("json", false, "Output JSON data.")
		flagAll   = flag.Bool("all", false, "Print all Unicode code points.")
	)
	flag.Usage = usage
	flag.Parse()

	if *flagHelp || *flagLHelp {
		help()
		return
	}

	var p printer
	if *flagJSON {
		p = &jsonPrinter{}
	} else {
		p = &textPrinter{}
	}

	args := flag.Args()

	var rs []rune

	if !*flagAll {
		lastIx := -1
		for i, arg := range args {
			if len(arg) == 0 {
				continue
			}
			if arg == "-" {
				lastIx = i
				break
			}

			var nums []int
			parts := strings.Split(arg, "-")
			if len(parts) > 2 {
				fmt.Fprintf(os.Stderr, "invalid rune argument: too many parts in range %s\n", arg)
				os.Exit(1)
			}
			for _, part := range parts {
				if strings.HasPrefix(part, "u+") || strings.HasPrefix(part, "U+") {
					part = "0x" + part[2:]
				}
				n, err := strconv.ParseUint(part, 0, 32)
				if err != nil {
					fmt.Fprintf(os.Stderr, "invalid rune argument: %s\n", arg)
					os.Exit(1)
				}
				nums = append(nums, int(n))
			}

			if len(nums) == 1 {
				rs = append(rs, rune(nums[0]))
				continue
			}
			rs = append(rs, runesInRange(nums[0], nums[1])...)
		}

		// if there are remaining arguments, treat them as strings to print the
		// runes of.
		args = args[lastIx+1:]
		for _, arg := range args {
			rs = append(rs, runesSet(arg)...)
		}
	}

	count := len(rs)
	if *flagAll {
		count = int(unicode.MaxRune)
	}

	if err := p.printStart(os.Stdout, count); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}

	if *flagAll {
		for i := 0; i <= unicode.MaxRune; i++ {
			if utf8.ValidRune(rune(i)) {
				if err := printRune(p, rune(i)); err != nil {
					fmt.Fprintln(os.Stderr, err)
					os.Exit(1)
				}
			}
		}
	} else {
		if err := printRunes(p, rs); err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
	}

	if err := p.printEnd(); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}

func runesInRange(start, end int) []rune {
	rs := make([]rune, 0, end-start+1)
	for i := start; i <= end; i++ {
		rs = append(rs, rune(i))
	}
	return rs
}

// returns a slice of runes where each distinct rune in arg is returned.
func runesSet(arg string) []rune {
	rs := make([]rune, len(arg))
	for i, r := range arg {
		rs[i] = r
	}
	return rs
}

func usage() {
	const usageMsg = `usage: runes [-h] [-json] [CODEPT ...] [START-END ...] [- STRING ...]`
	fmt.Println(usageMsg)
}

func help() {
	const msg = `
The runes command prints information about Unicode code points. Specific code
points can be requested as arguments, and ranges of code points are supported
(e.g. 0x17-0x60). Code points starting with '0x' or 'u+' are considered in
hexadecimal (the 'x' and 'u' are case insensitive), otherwise the number is
treated as decimal.

A single dash argument '-' can be used so that subsequent arguments are treated
as strings for which each rune will be printed.

The output follows the order of runes as specified on the command-line,
the same rune will be printed multiple times if it is specified or included
in multiple arguments.

Flags:
  -h,-help           Display this message.
  -json              Output JSON data.
  -all               Print all Unicode code points.

Examples:
    runes -all
    runes -json 0x2318 40-60
    runes u+1f970 0X55-0XA0 - "Some string"
`
	usage()
	fmt.Println(msg)
}