src/Environment/Unix/Matcher.php
public function getKey($input)
    {
        // try matching the key with plain text
        foreach ($this->text as $key => $code) {
            if ($code === $input) {
                return $key;
            }
        }

        // try matching the key with ascii
        foreach ($this->ascii as $key => $code) {
            if (chr($code) === $input) {
                return $key;
            }
        }

        // try matching the key with unicode
        foreach ($this->unicode as $key => $code) {
            if (unicode_to_string($code) === $input) {
                return $key;
            }
        }

        return false;
    }
public function getKey($input)
    {
        // try matching the key with plain text
        foreach ($this->text as $key => $code) {
            if ($code === $input) {
                return $key;
            }
        }

        // try matching the key with ascii
        foreach ($this->ascii as $key => $code) {
            if (chr($code) === $input) {
                return $key;
            }
        }

        // try matching the key with unicode
        foreach ($this->unicode as $key => $code) {
            if (unicode_to_string($code) === $input) {
                return $key;
            }
        }

        return false;
    }
Fetches a human readable key representation
based on a unicode/ascii/plain text charset

@param string $input unicode string

@return bool|int|string