[colm] add literal token syntax that allows ] ? * and +

[adrian-thurston]

[colm] add literal token syntax that allows ] ? * and +

[adrian-thurston]

maybe syntax should be

`'>*'

A single-quoted string preceded by a backtick. This is consistent with the shorter bare backtick form.

[adrian-thurston]

alternative to this approach is to not exclude ? + and *, but exclude ` and allow backtick literals to be end quoted.

`**** and `****` are equivalent.

When we want to repeat or optional a literal we can just end quote it.

[foo `,`*]

If we forget to the end quote it we end up with literal that (probably) does not exist.

[adrian-thurston]

Note that ] is still excluded from literals in positions 2+. The regex for literals would look like:

token backtick_lit /
        '`' .
            ^( ' ' | '\n' | '\t' ) .
            ^( ' ' | '\n' | '\t' | '`' | ']' )* .
        ( '`' | '' )
    /

[adrian-thurston]

Note this is consistent with optional end quotes on " and ' literals, although it is different in that it does not automatically include anything on the end, whereas optional " and ' end quotes cause newline to be included.

[adrian-thurston]

closed by b85782a