CHARACTER_REF

Used .NET classes

• Char (CHARACTER), CONVERT

Static methods used

• {CONVERT}.to_int32_char
• {CHARACTER}.to_upper, to_lower, is_lower_char, is_upper_char, is_digit_char, is_letter

Security notes

• None

Unhandled exceptions

• None

Other notes

Had to add/change preconditions in Base, because Base is ASCII and Base.NET is Unicode.
Added is_valid_character_code in INTEGER_REF for this purpose.
Also added min_value/max_value in CHARACTER_REF (0-255 for Base, 0-65535 for Base.NET).