On Jul 14, 2006, at 7:57, Eric A. wrote:
Ok. I get that using a module lets you establish
a namespace. Now for the other part of the question:
Why is the HTree module split up among half
a dozen files: parse.rb, and others??
This question sounds to me an awful lot like “why organise your code
at all? why not just use one big file?” For large projects (or even
small-to-medium projects that you expect other people to use), some
sort of functional organisation is necessary.
And come to think of it, is it possible that
the Comment and HTree classes are intuited by
Ruby, since they’re not explicitly defined,
in this file at least?
I don’t believe so. Class names are constants, and as such have to
be initialized somewhere before they’re they’re used. Try this example:
puts “hello world”
-:2: uninitialized constant Foo::Bar (NameError)
HTree::Comment and HTree::Text will be defined somewhere in one of
the files 'require’d into parse.rb (this includes the whole chain of
I’ll throw in my bit on the original question as well:
Rob S. wrote:
On 7/13/06, Eric A. [email protected] wrote:
[HTree parse.rb example]
What makes that a desirable way to structure
Probably to define the module HTree as the top level namespace.
In this case it also seems to encapsulate similar behaviour within a
single file: all the parsing methods for the various classes are
defined in a single location. More generally, if Java is “one class,
one file,” this approach would be “one behaviour, one file.”
In the Java world, each class is
in its own file. What are the advantages of
doing things this way, instead?
Quite similar to the Java model, I’d say, just substitute ‘behaviour’
for ‘class’ in all the points. For example, if, in Java, you’d say
that an error would be easy to localise because you know where the
class is defined, here you might say it’s easy to localise because
you know where that behaviour is defined.
Which one is more appropriate likely depends both on the code and the
coder. I imagine that for certain class structures where there are
many similarities in behaviour across the classes(e.g., there’s an
A#a, B#a, C#a, D#a, etc. that all do similar things), but little
interaction within classes (e.g., A#a and A#b don’t particularly care
about each other), grouping by behaviour makes a lot of sense, at
least to me.