Re: [netmod] rfc6991-bis: "token" type?

[Kent Watsen <[e-mail]>]

Hi Juergen,


> can you provide examples where this particular type is useful?

Useful in many contexts.  For instance:

    list user {
      key name;
      leaf name {
        type string;
      }
      leaf password {
        type string;
      }

The following instance document is valid:

  <user>
    <name/>
    <password/>
  </user>

Adding pattern statements works, but gets old after awhile.  A built-in type would be helpful.


> Or were
> you generally looking for a type to name things and the XSD token type
> was the first one that came your mind?

Yes, from past-life experience with XSD, I found "token" and "normalizedString" useful (https://www.w3schools.com/XML/schema_dtypes_string.asp <https://www.w3schools.com/XML/schema_dtypes_string.asp>).   However, those types
do not fully express what I really want (including, e.g., non-empty), which is:

a) a type for a non-empty, stripped, printable string that MAY contain internal 'space' characters.

b) a type for a non-empty, stripped, printable string that MAY NOT contain internal 'space' characters.

/kw


> If the goal is to define a type for identifiers, then we likely should
> follow the Unicode standard annex UAX-31 and make use of <XID_Start>
> <XID_Continue>, which is what I think Python3 and Rust are using as
> the basis for their notion of language identifiers (but then the
> Unicode definitions are also criticized as buggy). A challenge is that
> the definition of <XID_Start> and <XID_Continue> seems to evolve with
> the unicode version. And once you start digging into the various
> attempts of modern programming languages to support internationalized
> identifiers, you discover that this is far from trivial to get right.
> 
> /js
> 
> On Thu, Apr 18, 2019 at 04:51:21AM +0000, Kent Watsen wrote:
>> 
>> Many times in models I want a non-empty version of what XSD calls a "token":
>> 
>>    token    A string that does not contain line feeds,
>>             carriage returns, tabs, leading or trailing
>>             spaces, or multiple spaces.
>> 
>> So how about the following?
>> 
>>  typedef token {
>>      type string;
>>      length "1.max";         // non-empty (some expr do this already)
>>      pattern "[^\n\r\t"]+"   // no LFs, CRs, or Tabs
>>      pattern "[^ ].*";       // no leading space     (min-length 1?)
>>      pattern ".*[^ ]";       // no trailing space    (min-length 1?)
>>      pattern ".*[^ ][^ ].*"  // no multiple spaces   (min-length 2?)
>>  }
>> 
>> Kent // contributor
>> 
>> 
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> 
> -- 
> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
> Fax:   [phone]         <https://www.jacobs-university.de/>