Seems like Io's "forward" is a lot like "did-not-understand" (and similar mechanisms in Ruby/etc. languages), but it takes priority over messages that would've otherwise been understood.
Yes its same as did-not-understand/method_missing/__getattr__/AUTOLOAD but no it doesn't take priority over other defined messages.
For eg, If I change the first line in my code above to:
Builder := Object do (
foo := method (arg, write (arg))
)
Builder do (
h1 (
foo ("Foo here!")
p ("paragraph")
)
)
<h1>Foo here!<p>paragraph</p></h1>Actually, the article seems to be wrong? It seems to imply that this shouldn't work:
Io> x := Object clone do( forward := 0; a := 1 )
==> Object_0x1003a2e90:
a = 1
forward = 0
Io> x a
==> 1
Io> x b
==> 0
Io> x b := 2
==> 2
Io> x b
==> 2
The documentation clearly states for forward that: If an object doesn't respond to a message, it will invoke its "forward" method if it has one.
Mine (in perl) is more akin to Ruby's Builder by Jim Weirich (http://builder.rubyforge.org/) than out and out HTML builder.
BTW, other HTML builders have been mentioned on HN before: http://news.ycombinator.com/item?id=1518096