This repository contains an implementation of codecs mapping the RISC OS alphabets to Unicode and vice-versa. The RISC OS alphabets mostly follow the standards, but diverge in the C1 region and where the standards do not define characters.
The encodings registered here are the alphabets used by RISC OS, based on the standard Python codecs. The encodings are registered in the following format:
riscos-alphabet-<alphabet number>
riscos-<lower case alphabet name as given by UK territory>
This should allow the encodings to be located programatically whichever of those values are used. The 'riscos-alphabet-111' and 'riscos-utf8' encodings are registered for orthoginality, and map directly to the 'utf-8' encoding.
The encodings supplied here include characters in the C1 region (0x80-0x9F) to match the representations within RISC OS. Two characters, 0x84 and 0x87 are not representable.
The 0x84 character is the 'resize' character, which does exist as a character in unicode, but encodes into surrogates within Python. Because this breaks the single-character mapping implementation used here, it has been mapped to the replacement character.
The 0x87 character is represented as '87' in the character set and otherwise unmapped in RISC OS, so has been mapped to the replacement character.
Some character sets, in their specification define that code points must not be used, which means that they are not defined within the Python codecs. As characters do exist at those code points within RISC OS, they should be provided with a mapping, but at present are left with replacement the character.
Importing this module will immediately register the new codecs.
This module is intentionally Python 2/3 compatible as Python 2 code will remain for some time.