camel.go

package stringcase

import "bufio"
import "github.com/reiver/go-whitespace"
import "strings"
import "unicode"

// ToCamelCase converts the string to "camelCase" and returns it.
func ToCamelCase(s string) string {

	// Here we use a similar hack that the Golang strings.Title() func uses,
	// which uses the strings.Map() func but (and this is the hack'y part)
	// depends on the interation order of strings.Map().
	//
	// See: https://golang.org/src/strings/strings.go#L519
	//
	// Specifically, assumes it iterates from beginning to end.
	//
	first := true
	prev := ' '
	result := strings.Map(
		func(r rune) rune {
			if first && (whitespace.IsWhitespace(prev) || '_' == prev || '-' == prev) {
				first = false
				prev = r
				return unicode.ToLower(r)
			} else if !first && (whitespace.IsWhitespace(prev) || '_' == prev || '-' == prev) {
				prev = r
				return unicode.ToTitle(r)
			} else if whitespace.IsWhitespace(r) || '_' == r || '-' == r {
				prev = r
				return -1
			} else {
				prev = r
				return unicode.ToLower(r)

			}
		},
		s)

	// Return
	return result
}

// FromCamelCase converts the "camelCase" string to a spaced string "camel Case"
// and returns it.
func FromCamelCase(s string) string {
	scanner := bufio.NewScanner(strings.NewReader(s))
	scanner.Split(bufio.ScanRunes)
	prevIsLowercase := false
	result := ""
	for scanner.Scan() {
		r := scanner.Text()
		if r == strings.ToLower(r) {
			prevIsLowercase = true
		} else if r == strings.ToUpper(r) {
			if prevIsLowercase {
				result += " "
			}
			prevIsLowercase = false
		}

		result += r
	}

	// Return
	return result
}