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
