Function canonicalise_char 

fn canonicalise_char(ch: char) -> char

Additional mappings of Unicode input to prevent user confusion.

We use the centre dot (“·”, U+00B7) as a decimal point, but also accept “.” U+002E, because the latter is likely to be a common choice.

We also provide “:” as a synonym for “h” in setting the hold bit in order to accept source code from earlier papers which used the older convention, such as H. Philip Peterson’s “Some Examples of TX-2 Programming” (Lincoln Lab memo 6M-5780, 23 July 1958).