# Ara's double\_x : generate xml? **URL:** \ **Category:** Ruby\ **Created:** [March 27, 2006, 5:00pm UTC](https://www.ruby-forum.com/t/aras-double-x-generate-xml/56046 "2006-03-27T17:00:46Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![itsme213](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/258eb7/32.png) [@itsme213](https://www.ruby-forum.com/u/itsme213)\ **Post date:** [March 27, 2006, 5:00pm UTC](https://www.ruby-forum.com/t/aras-double-x-generate-xml/56046/1 "2006-03-27T17:00:46Z")
Does this library support generating of xml (not xhtml)? what’s the top level call? I tried xml\_ { …} and it dies with irb(main):021:0\> doc = xml\_ { p\_ “a” } NoMethodError: undefined method `create' for nil:NilClass from c:/ruby/lib/ruby/gems/1.8/gems/xx-0.1.0/lib/xx.rb:197:in`method\_missing’ from (eval):10:in `xml_' from c:/ruby/lib/ruby/gems/1.8/gems/xx-0.1.0/lib/xx.rb:208:in`send’ from c:/ruby/lib/ruby/gems/1.8/gems/xx-0.1.0/lib/xx.rb:208:in `method\_missing’ from (irb):21 from :0 irb(main):022:0\> Thanks. ---
**Author:** ![itsme213](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/258eb7/32.png) [@itsme213](https://www.ruby-forum.com/u/itsme213)\ **Post date:** [March 27, 2006, 5:05pm UTC](https://www.ruby-forum.com/t/aras-double-x-generate-xml/56046/2 "2006-03-27T17:05:55Z")
On Mon, 27 Mar 2006, itsme213 wrote: > ``` > from c:/ruby/lib/ruby/gems/1.8/gems/xx-0.1.0/lib/xx.rb:208:in > > ``` > > `method\_missing’ > from (irb):21 > from :0 > irb(main):022:0\> > > Thanks. you just need to mixin the method you want, in this case the xml methods: harp:~ \> cat a.rb require ‘xx’ include XX::XML puts xml\_{ p\_{ “a” } } harp:~ \> ruby a.rb \ a regards. -a ---
**Author:** ![itsme213](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/258eb7/32.png) [@itsme213](https://www.ruby-forum.com/u/itsme213)\ **Post date:** [March 27, 2006, 5:14pm UTC](https://www.ruby-forum.com/t/aras-double-x-generate-xml/56046/3 "2006-03-27T17:14:47Z")
thank you sir. love the library. is the ‘\_’ convention something that is (or should be) configurable? i’m also looking forward to experimenting with traits. it sounds like something that could be used for recording meta-data in lots of places, including things like nitro/og. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote in message news:removed\_email\_address@domain.invalid… ---
**Author:** ![itsme213](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/258eb7/32.png) [@itsme213](https://www.ruby-forum.com/u/itsme213)\ **Post date:** [March 27, 2006, 6:15pm UTC](https://www.ruby-forum.com/t/aras-double-x-generate-xml/56046/4 "2006-03-27T18:15:24Z")
On Tue, 28 Mar 2006, itsme213 wrote: > thank you sir. love the library. is the ‘\_’ convention something that is (or > should be) configurable? it is actually configurable. you do something like xx\_configure “method\_missing”, XX::STRICT # tag methods require ‘_’ xx\_configure “method\_missing”, XX::CRAZY\_LIKE\_A\_HELL # tag methods no not require '_’ in your class. you example is a great example of why **not** to do that however, without the ‘\_’ this xml{ p ‘a’ } would call ruby’s built-in ‘p’ method. this would fail, but silently. one of the big differences with xx and other html/xml generation libs is that it’s **designed** to be mixed into other classes to give them html generation capbilities (a la widgets). the thing is, when you mixin to a class like, say, Array, you’ve already lost a huge part of you namespace like ‘length’, ‘find’, ‘each’, etc. none of these methods will trigger method missing and so cannot be tag methods. this is less a big deal for html than for xml, which can contain pretty much anything as tag names. if one uses a blanket method missing approach, or even a receiver as the tag generator, one simply cannot generate xml using o.type{ } # oops, all object have ‘type’ o.id{ } # oops, all object have ‘id’ you can use a BlankSlate here… but then you’ve also lost the ability to mixin rather than agregate. > i’m also looking forward to experimenting with traits. it sounds like > something that could be used for recording meta-data in lots of places, > including things like nitro/og. for sure. it’s one of the things it was designed for. being able to get back list of traits is very valuable. for instance, this line, taken from an ‘initialize’ method, iterates over all of this object’s class traits and creates an instance trait for the current object that gets a deep copy of the class trait as the default value: klass = self.class mcp = lambda{|obj| Marshal::load(Marshal::dump(obj))} klass::class\_traits.each{|r,w| klass::trait®{ mcp[klass.send®]}} so basically it says : “i have all the same traits as my class and i’ll bootstrap myself from the values of those traits which have been parameterized in my class” this reason this is done is that this class is part of a hierarchy where each subclass adds more traits to parameterize the class. with this generic line i can make any instance of that subclass bootstrap properly with no new code. so class Parent class\_trait ‘p’ =\> 42 def intialize … end end class Child \< Parent class\_trait ‘c’ =\> 42.0 end child = Child::new and here ‘child’ would have the **instance** traits ‘a’ and ‘b’ with default values gotten from the class method. regards. -a ---
**Author:** ![itsme213](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/258eb7/32.png) [@itsme213](https://www.ruby-forum.com/u/itsme213)\ **Post date:** [March 27, 2006, 7:14pm UTC](https://www.ruby-forum.com/t/aras-double-x-generate-xml/56046/5 "2006-03-27T19:14:06Z")
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote in message > it is actually configurable. you do something like I did not mean a blanket method\_missing. My real question was: - if I have a conflict with the ‘\*\_’ convention, & - I have another convention that I’d like to use e.g. ‘\*\_x’ would I be able to configure to use that convention? > this reason this is done is that this class is part of a hierarchy where > each > subclass adds more traits to parameterize the class. Is it possible to have different ways of combining up the class/module chains? e.g. override? append? other? Thanks! ---
**Author:** ![itsme213](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/258eb7/32.png) [@itsme213](https://www.ruby-forum.com/u/itsme213)\ **Post date:** [March 27, 2006, 7:28pm UTC](https://www.ruby-forum.com/t/aras-double-x-generate-xml/56046/6 "2006-03-27T19:28:19Z")
On Tue, 28 Mar 2006, itsme213 wrote: > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote in message > > > it is actually configurable. you do something like > > I did not mean a blanket method\_missing. My real question was: > > - if I have a conflict with the ‘\*\_’ convention, & > - I have another convention that I’d like to use e.g. ‘\*\_x’ > would I be able to configure to use that convention? ah. no. however, it would be a 3 minute exercise to add this capability. would you like me too? > > this reason this is done is that this class is part of a hierarchy where > > each subclass adds more traits to parameterize the class. > > Is it possible to have different ways of combining up the class/module > chains? e.g. override? append? other? hmm. override is the default. let me think about append. regards. -a ---
**Author:** ![itsme213](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/i/258eb7/32.png) [@itsme213](https://www.ruby-forum.com/u/itsme213)\ **Post date:** [March 27, 2006, 10:19pm UTC](https://www.ruby-forum.com/t/aras-double-x-generate-xml/56046/7 "2006-03-27T22:19:12Z")
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote in message > ah. no. however, it would be a 3 minute exercise to add this capability. > would you like me too? If you think it would be generally useful. For right now I’m fine with ‘\_’. > > Is it possible to have different ways of combining up the class/module > > chains? e.g. override? append? other? > > hmm. override is the default. let me think about append. A trait of a trait, perhaps 😉