[x3d-public] SFImage regex
John Carlson
yottzumm at gmail.com
Fri Jun 8 15:26:45 PDT 2018
Your mixing SFRotation and ScaleOrientation in your code. Not sure if you
caught it or not.
On Fri, Jun 8, 2018, 6:17 PM Don Brutzman <brutzman at nps.edu> wrote:
> onward...
>
> On 6/8/2018 11:36 AM, Andreas Plesch wrote:
> > On Fri, Jun 8, 2018 at 2:19 AM Don Brutzman <brutzman at nps.edu <mailto:
> brutzman at nps.edu>> wrote:
> >
> > i tried testing this against PixelTexture value
> >
> > 2 4 3 0xff0000 0xffff00 0x007700 0xff0077 0x0000ff 0xff7700
> 0x00ff77 0x888888
> >
> > from scene
> >
> >
> http://X3dGraphics.com/examples/X3dForWebAuthors/Chapter05AppearanceMaterialTextures/PixelTexture.x3d
> >
> > using https://regex101.com and that tests satisfactorily.
> >
> > however the default value of '0 0 0' fails according to XML Spy, so
> there is still a problem here...
> >
> > I could confirm that this is due to XML regex expressions not
> considering anchors, in particular the $ end of string anchor.
>
> OK... haven't used them elsewhere in the regexes. Further info:
>
> Start of String and End of String Anchors
> https://www.regular-expressions.info/anchors.html
>
> parenthetically OBTW also found this reference, constructing a
> nondeterministic finite automaton (NFA). Whoa.
>
> Ken Thompson's construction algorithm
> https://en.wikipedia.org/wiki/Thompson%27s_construction_algorithm
>
> > Without anchors the regex becomes longer and a bit more complicated,
> still not allowing leading zeroes or commas:
> >
> >
> ^\s*(\d|[1-9]\d+)(\s+(\d|[1-9]\d+)){2}(\s+((0x([a-f]|[A-F}|\d]){1,8})|[1-9]\d+|\d))*\s*$
> (allowing for leading and trailing white space, and anchoring)
> >
> >
> (\d|[1-9]\d+)(\s+(\d|[1-9]\d+)){2}(\s+((0x([a-f]|[A-F}|\d]){1,8})|[1-9]\d+|\d))*
> (untested XML version which is implicitly anchored, assuming the whitespace
> collapsing restriction)
>
> Am using this second form as our next version, consistent with other
> approaches provided.
>
> for MFImage, adapted it with a prepended ( and then appended
> (\s)*(,)?(\s)*)* in order to consume intermediate whitespace plus single
> optional comma.
>
> > https://regex101.com/r/CJ1h80/4/tests
>
> wow that saved regex pattern + rationale is utterly awesome. screenshot
> attached and online at
>
>
> http://www.web3d.org/specifications/images/Regex101SFImageTestingScreenshot.png
> Your customized regex page also answers how we might connect regex online
> testing directly to each type on the regex page... link now added at
>
>
> http://www.web3d.org/specifications/X3dRegularExpressions.html#SFImage
>
> > lets everybody test and improve this regex with some of the more
> challenging cases as unit tests, including the default 0 0 0 case.
>
> all in! as you will see, the site allowed me to add a test corresponding
> to the PixelTexture.x3d and PixelTextureBW.x3d models from X3D for Web
> Authors (X3D4WA) archive.
>
> > It is more important to come up with examples which almost match but
> actually should not match than testing conforming examples such as the
> web3d example library. Of course there should not be any false positives,
> eg. not matching examples which are in fact fine.
>
> well OK but not a worry. relative priorities are all good when we "divide
> + conquer" like this.
>
> testing all archive scenes helps reveal unintended side effects from
> changes as well.
>
> ... also OBE. building on last night's progress, I have added
>
>
> =========================================================================================
>
> http://www.web3d.org/specifications/java/javadoc/org/web3d/x3d/jsail/fields/SFVec3fObject.html#validate--
>
> validate() methods to each of the simple types that provide an error
> message when a value fails. excerpt:
>
> public SFVec3fObject setValueByString (String newValue) throws
> InvalidFieldValueException
> {
> if (newValue == null)
> newValue = new String(); // Principle of Least
> Astonishment (POLA)
> //
> https://en.wikipedia.org/wiki/Principle_of_least_astonishment
>
> if (!SFVec3fObject.matches(newValue)) // regex test
> {
> String errorNotice = "*** Regular expression (regex)
> failure, new SFVec3fObject(" + newValue + ")";
> validationResult.append(errorNotice).append("\n");
> }
>
> =========================================================================================
>
> http://www.web3d.org/specifications/java/javadoc/org/web3d/x3d/jsail/Grouping/TransformObject.html#validate--
>
> validate() methods for each field to the comprehensive validate() checks
> in each node object.
>
> excerpt from TransformObject validate() method:
>
> setScaleOrientation(getScaleOrientation()); // exercise field
> checks, simple types
> validationResult.append((new
> SFRotationObject(getScaleOrientation())).validate()); // regex check of
> corresponding String value
>
> setTranslation(getTranslation()); // exercise field checks, simple
> types
> validationResult.append((new
> SFVec3fObject(getTranslation())).validate()); // regex check of
> corresponding String value
> [...]
>
> =========================================================================================
>
> just ran some initial tests, it revealed a copy/paste error on my part
> that was fixed. update uploads in progress.
>
> as before, am only experimenting on the x3d-4.0 schema and X3DUOM object
> model with these regex tests. will propagate across prior versions once
> stable.
>
> full regression tests on example archives are now poised to run, will
> follow up at a later time. of course those kinds of tests can also find
> errors in X3D scene content as well as the regexes themselves.
>
> > The new regex had to split the matching of the 3 initial integers into
> two parts. First matching the first integer, then matching at least one
> whitespace followed by an integer, twice.
> > For optional value matching, the order is now at least one whitespace
> followed by a number rather than number then whitespace, to avoid requiring
> whitespace at the very end. This in turn required an ordering of the or
> number branches to hex, then multidigits, then single digits for reasons I
> hesitate to fully explore but probably having to do with greediness.
> > The new regex also uses the \d and \s classes for conciseness, as well
> as Leonards idea to limit hex values to at most 8 characters.
>
> interesting certainly. i got as far as i could today.
>
> improved guidance:
> ==================
> http://www.web3d.org/specifications/X3dRegularExpressions.html#X3dPatterns
>
> General regex design considerations for X3D XML Schema include the
> following.
> * For numeric types, leading sign characters (+ or -) are optionally
> present.
> * For numeric types, leading zeroes are not allowed, except for an
> optional leading zero preceding the decimal point when the significand is
> only fractional.
> * Intermediate commas are treated as whitespace, but only allowed between
> each singleton value. For example, SFVec3f 3-tuple values within an MFVec3f
> array do not contain comma characters.
> * Careful design allows use of regexes that can also be adapted to
> JavaScript/JSON, Java and other language environments.
> * These regexes all assume that leading/trailing whitespace has been
> removed. It is possible to prepend/append regex constructs such as (\s)+ to
> consume outer whitespace.
> ==================
>
> > TODO: clarify commas, spec. says commas in SF fields are whitespace, so
> should be allowed. But allowing in SF fields and then not allowing them in
> the corresponding MF field for other than set separation is quite confusing.
>
> I have been watching for years and have yet to see (or imagine) any scene
> with pathological commas that deserved to be ignored. sometimes whitespace
> normalization was worthwhile; most often data errors had occurred which
> were otherwise hidden and mysterious failures.
>
> The worst error is the one you cannot find. Strictness of commas
> (disallowed within n-tuples, allowed between n-tuples) is A Good Thing that
> leads to quality content and is not a blocker for any other content.
>
> > Give it a spin, -Andreas
> >
> > in any case, great start! have added it to X3D v4.0 schema for
> further experimentation, in this case under the annotations until working
> better.
> >
> > deployed online. however can't get svn to work here so checkins
> will be another time.
> >
> >
> http://www.web3d.org/specifications/X3dSchemaDocumentation4.0/x3d-4.0_SFImage.html
> >
> >
> > On 6/7/2018 11:11 AM, Andreas Plesch wrote:
> > > Ok, let's give it a try:
> > >
> > > [ \t]*(([0-9]|[1-9][0-9]+)([
> ]+|$)){3}(([0-9]|([1-9][0-9]+)|(0x([0-9]|[a-f]|[A-F])+))([ ]+|$))*
> > >
> > > In words:
> > >
> > > match any leading white space followed by
> > > exactly three times the following
> > > - one of the following
> > > - either a single digit (including 0) or
> > > - a two or more digit number starting with a 1 to 9 digit
> > > - followed by either
> > > - one or more spaces
> > > - or the end of the string (accommodating the default '0 0 0'
> case)
> > > then optionally followed zero or more times by
> > > - one of the following
> > > - either a single digit (including 0) or
> > > - a two or more digit number starting with a 1 to 9 digit
> > > - 0x followed by at least one of
> > > - a single digit or
> > > - a to f letter or
> > > - A to F letter
> > > - followed by either
> > > - one or more spaces
> > > - or the end of the string
>
> all the best, Don
> --
> Don Brutzman Naval Postgraduate School, Code USW/Br
> brutzman at nps.edu
> Watkins 270, MOVES Institute, Monterey CA 93943-5000 USA +1.831.656.2149
> X3D graphics, virtual worlds, navy robotics
> http://faculty.nps.edu/brutzman
>
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