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camelcase.go
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camelcase.go
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package camelcase
import (
"unicode"
"unicode/utf8"
)
// Split splits the camelcase word and returns a list of words. It also
// supports digits. Both lower camel case and upper camel case are supported.
// For more info please check: http://en.wikipedia.org/wiki/CamelCase
// Splitting rules
//
// 1) If string is not valid UTF-8, return it without splitting as
// single item array.
// 2) Assign all unicode characters into one of 4 sets: lower case
// letters, upper case letters, numbers, and all other characters.
// 3) Iterate through characters of string, introducing splits
// between adjacent characters that belong to different sets.
// 4) Iterate through array of split strings, and if a given string
// is upper case:
// if subsequent string is lower case:
// move last character of upper case string to beginning of
// lower case string
func Split(src string) (entries []string) {
// don't split invalid utf8
if !utf8.ValidString(src) {
return []string{src}
}
entries = []string{}
var runes [][]rune
lastClass := 0
class := 0
// split into fields based on class of unicode character
for _, r := range src {
switch true {
case unicode.IsLower(r):
class = 1
case unicode.IsUpper(r):
class = 2
case unicode.IsDigit(r):
class = 3
default:
class = 4
}
if class == lastClass {
runes[len(runes)-1] = append(runes[len(runes)-1], r)
} else {
runes = append(runes, []rune{r})
}
lastClass = class
}
// handle upper case -> lower case sequences, e.g.
// "PDFL", "oader" -> "PDF", "Loader"
for i := 0; i < len(runes)-1; i++ {
if unicode.IsUpper(runes[i][0]) && unicode.IsLower(runes[i+1][0]) {
runes[i+1] = append([]rune{runes[i][len(runes[i])-1]}, runes[i+1]...)
runes[i] = runes[i][:len(runes[i])-1]
}
}
// construct []string from results
for _, s := range runes {
if len(s) > 0 {
entries = append(entries, string(s))
}
}
return
}