Functions operating over Chars.
The representation of a Char is backend dependent,
for the C backend, it is a Unicode code point.
Convert the number to its backend dependent (usually Unicode) Char equivelent.
Returns true if the character is in the ranges [A-Z][a-z].
Returns true if the character is in the ranges [A-Z][a-z][0-9]
Returns true if the character is a control character.
Returns true if the character is in the range [0-9]
Returns true if the character is a hexadecimal digit i.e. in the range [0-9][a-f][A-F]
Returns true if the character is in the range [a-z]
Returns true if the character represents a new line.
Returns true if the character is an octal digit.
Returns true if the character is a whitespace character.
Returns true if the character is in the range [A-Z].
Return the backend dependent (usually Unicode) numerical equivelent of the Char.
Convert a letter to the corresponding lower-case letter, if any.
Non-letters are ignored.
Convert a letter to the corresponding upper-case letter, if any.
Non-letters are ignored.