regex in the spec

MHonArc v2.5.0b2 -->
















xacml message






[Date Prev]
 | [Thread Prev]
 | [Thread Next]
 | [Date Next]

--

[Date Index]
 | [Thread Index]
 | [List Home]








Subject: regex in the spec




From: Bill Parducci <>
To: xacml <>
Date: Mon, 03 May 2004 14:59:40 -0700






i was looking at the regular expressions during the f2f and wanted to toss out 
some thoughts on it after looking into it a bit more.

first, in the spec we don't really say much in terms of regular expression 
conformance and that kinda worries me. i am thinking that maybe we should call 
out a generally accepted flavor of regex, then pare it down as (if) necessary 
for our spec.

second, i was looking at the expressions themselves and am a little 
confused--because, i think, the current verbage uses *perl* regex and i was 
thinking that we would be using *posix* regex, specifically 'POSIX 1003.2' 
flavored expressions--by this:

<xs:pattern value="(\d+\.)*\d+"/>

i assume that we want to cover this:

1
1.1
1.2.3
1123.2386576.93783636.736235252
...

using posix regex i would write this as:

<xs:pattern value= "[0-9]+(\.([0-9])+)*" />

besides the syntactical difference i would move the literal '.' to the predicate 
so that '1.' isn't valid ;o)

as to "Simple type VersionMatchType":

<xs:pattern value="((\d+|\*)\.)*(\d+|\*|\+)"/>

if the idea here is to simply include a direct regular expressions i suggest 
using the same:

<xs:pattern value= "[0-9]+(\.([0-9])+)*" />

going this route ensures that just about any language that operates on regular 
expressions will support the syntax and that there is a tangible reference point 
for the semantics.

thoughts?

b