Proposed new variant subtag: pre1917

Doug Ewell doug at
Wed Sep 15 15:46:10 CEST 2010

Philip Newton <philip dot newton at gmail dot com> wrote:

> Remember that variant subtags may not be longer than eight characters;
> also, if they start with a digit, they must be followed by precisely
> three characters for a total length of four characters (and if they
> start with a letter, they must be followed by at least four characters
> for a minimum length of five characters).

This is a common misreading of the ABNF for variant subtags:

variant       = 5*8alphanum         ; registered variants
              / (DIGIT 3alphanum)

The first production -- 5*8 alphanum -- means that subtags 5 to 8
letters in length can begin with either a letter or a digit.  So
whatever its other advantages or disadvantages might be, '1918orth' is
just as valid syntactically as 'orth1918'.

Doug Ewell | Thornton, Colorado, USA |
RFC 5645, 4645, UTN #14 | ietf-languages @ is dot gd slash 2kf0s ­

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