vendor/github.com/stoewer/go-strcase/helper.go

// Copyright (c) 2017, A. Stoewer <adrian.stoewer@rz.ifi.lmu.de>
// All rights reserved.

package strcase

// isLower checks if a character is lower case. More precisely it evaluates if it is
// in the range of ASCII character 'a' to 'z'.
func isLower(ch rune) bool {
	return ch >= 'a' && ch <= 'z'
}

// toLower converts a character in the range of ASCII characters 'A' to 'Z' to its lower
// case counterpart. Other characters remain the same.
func toLower(ch rune) rune {
	if ch >= 'A' && ch <= 'Z' {
		return ch + 32
	}
	return ch
}

// isLower checks if a character is upper case. More precisely it evaluates if it is
// in the range of ASCII characters 'A' to 'Z'.
func isUpper(ch rune) bool {
	return ch >= 'A' && ch <= 'Z'
}

// toLower converts a character in the range of ASCII characters 'a' to 'z' to its lower
// case counterpart. Other characters remain the same.
func toUpper(ch rune) rune {
	if ch >= 'a' && ch <= 'z' {
		return ch - 32
	}
	return ch
}

// isSpace checks if a character is some kind of whitespace.
func isSpace(ch rune) bool {
	return ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r'
}

// isDelimiter checks if a character is some kind of whitespace or '_' or '-'.
func isDelimiter(ch rune) bool {
	return ch == '-' || ch == '_' || isSpace(ch)
}