toLower package:rio

toLower :: Char -> Char
rio RIO.Char
Convert a letter to the corresponding lower-case letter, if any. Any other character is returned unchanged.
toLower :: Text -> Text
rio RIO.Text
O(n) Convert a string to lower case, using simple case conversion. Subject to fusion. The result string may be longer than the input string. For instance, "İ" (Latin capital letter I with dot above, U+0130) maps to the sequence "i" (Latin small letter i, U+0069) followed by " ̇" (combining dot above, U+0307).
toLower :: Text -> Text
rio RIO.Text.Lazy
O(n) Convert a string to lower case, using simple case conversion. Subject to fusion. The result string may be longer than the input string. For instance, the Latin capital letter I with dot above (U+0130) maps to the sequence Latin small letter i (U+0069) followed by combining dot above (U+0307).