97 lines
3.0 KiB
Go
97 lines
3.0 KiB
Go
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// Package english provides utilities to generate more user-friendly English output.
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package english
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import (
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"fmt"
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"strings"
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)
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// These are included because they are common technical terms.
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var specialPlurals = map[string]string{
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"index": "indices",
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"matrix": "matrices",
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"vertex": "vertices",
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}
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var sibilantEndings = []string{"s", "sh", "tch", "x"}
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var isVowel = map[byte]bool{
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'A': true, 'E': true, 'I': true, 'O': true, 'U': true,
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'a': true, 'e': true, 'i': true, 'o': true, 'u': true,
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}
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// PluralWord builds the plural form of an English word.
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// The simple English rules of regular pluralization will be used
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// if the plural form is an empty string (i.e. not explicitly given).
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// The special cases are not guaranteed to work for strings outside ASCII.
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func PluralWord(quantity int, singular, plural string) string {
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if quantity == 1 {
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return singular
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}
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if plural != "" {
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return plural
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}
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if plural = specialPlurals[singular]; plural != "" {
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return plural
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}
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// We need to guess what the English plural might be. Keep this
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// function simple! It doesn't need to know about every possiblity;
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// only regular rules and the most common special cases.
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//
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// Reference: http://en.wikipedia.org/wiki/English_plural
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for _, ending := range sibilantEndings {
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if strings.HasSuffix(singular, ending) {
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return singular + "es"
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}
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}
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l := len(singular)
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if l >= 2 && singular[l-1] == 'o' && !isVowel[singular[l-2]] {
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return singular + "es"
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}
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if l >= 2 && singular[l-1] == 'y' && !isVowel[singular[l-2]] {
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return singular[:l-1] + "ies"
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}
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return singular + "s"
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}
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// Plural formats an integer and a string into a single pluralized string.
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// The simple English rules of regular pluralization will be used
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// if the plural form is an empty string (i.e. not explicitly given).
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func Plural(quantity int, singular, plural string) string {
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return fmt.Sprintf("%d %s", quantity, PluralWord(quantity, singular, plural))
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}
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// WordSeries converts a list of words into a word series in English.
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// It returns a string containing all the given words separated by commas,
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// the coordinating conjunction, and a serial comma, as appropriate.
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func WordSeries(words []string, conjunction string) string {
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switch len(words) {
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case 0:
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return ""
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case 1:
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return words[0]
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default:
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return fmt.Sprintf("%s %s %s", strings.Join(words[:len(words)-1], ", "), conjunction, words[len(words)-1])
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}
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}
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// OxfordWordSeries converts a list of words into a word series in English,
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// using an Oxford comma (https://en.wikipedia.org/wiki/Serial_comma). It
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// returns a string containing all the given words separated by commas, the
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// coordinating conjunction, and a serial comma, as appropriate.
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func OxfordWordSeries(words []string, conjunction string) string {
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switch len(words) {
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case 0:
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return ""
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case 1:
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return words[0]
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case 2:
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return strings.Join(words, fmt.Sprintf(" %s ", conjunction))
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default:
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return fmt.Sprintf("%s, %s %s", strings.Join(words[:len(words)-1], ", "), conjunction, words[len(words)-1])
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}
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}
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