Subject: [Lager] [lager] #15 (specification): Clarify when/not-when use on char/range

From: "lager issue tracker" <[email-masked]>
Date: Wed, 19 Aug 2015 16:32:31 -0000

#15: Clarify when/not-when use on char/range

 In the current version of the draft, there is no clear mention that both
 char and range elements accept when/not-when attributes.

 Section 4.1 Sequence says
 {{{
    As an alternative to using sequences to define a required context, a
    "char" or "range" element may specify conditional context using an
    optional "when" attribute as described below in Section 4.2.5.
 }}}
 (only mention of when attribute)

 Section 4.2.5 Conditional Variants is as follows:
 {{{
    As described in Section 4.1 a "when" or "not-when" attribute may also
    be specified to any "char" element in the data section to define
    required or prohibited contextual conditions under which a code point
    is valid.
 }}}
 (only deals with char elements).

 Section 5.3.9. Example rule from IDNA2008 gives the following example:
 {{{
        <data>
           <range first-cp="0660" last-cp="0669" not-when="mixed-digits"
                  tag="arabic-indic-digits" />
           <range first-cp="06F0" last-cp="06F9" not-when="mixed-digits"
                  tag="extended-arabic-indic-digits" />
        </data>
 }}}

 And the provided RNC file does not allow when/not-when attribute on range:
 {{{
  ## Representation of a range of code points
  range = element range {
      attribute first-cp { code-point },
      attribute last-cp { code-point },
      attribute comment { text }?,
      attribute tag { tags }?,
      attribute ref { text }?
  }
 }}}

 Having some text to explicitly tell readers that when/not-when attributes
 are allowed on char/range elements would make it easier for understanding
 the specs.

 Maybe we can move the quoted text from section 4.2.5 to a new section
 between 4.2 Variants and 4.3 Annotations, something like "Contextual
 Conditions"?

-- 
-------------------------------------+-------------------------------------
 Reporter:                           |      Owner:  draft-ietf-lager-
  [email-masked]    |  [email-masked]
     Type:  defect                   |     Status:  new
 Priority:  major                    |  Milestone:
Component:  specification            |    Version:
 Severity:  -                        |   Keywords:
-------------------------------------+-------------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/lager/trac/ticket/15>
lager <http://tools.ietf.org/lager/>