From: "David A. Black" <dblack@...>
Date: 2005-09-12T09:15:11+09:00
Subject: Re: RCR to modify #puts and #print inside ERB

Hi --
On Mon, 12 Sep 2005, Mark Hubbart wrote:

> Hi,
>
> On 9/11/05, David A. Black <dblack@wobblini.net> wrote:
>>
>> If you want puts and print to behave anomalously, that's OK.  But
>> there's no mystery to why they don't.  They behave exactly the same
>> way every other method behaves.  I don't think the *absence* of a
>> "magic" or special case should be a source of wonder :-)
>
> That's the thing; to those of us who don't see it as just "fancy
> string interpolation", the *current* behavior is anomalous, not the
> suggested behavior. The current behavior actually seems rather magic,
> until you discover why it behaves that way, after which it just feels
> poorly implemented.

When a method is called in a <%= %> block, that part of the template
gets filled in with a string representation of its return value.  This
behavior, as far as I know, is consistent across all method calls.  If
any one or two methods get special treatment, that's an anomaly (or
exception, or special case, or whatever).  That's all I mean.  There
is *already* a technical principle at work.

[...]

> I don't see this as being about adding "magic" to the implementation.
> If you are of the mindset that the template is concatting to a string,
> the puts idea doesn't make sense; but if you see it as printing to an
> output stream (with the whole _erbout thing just being an
> implementation issue), then the lack of a working print/puts is what
> doesn't make sense.

If you decide a priori that ERB is a failed implementation of
something other than itself, rather than a successful implementation
of what it actually is, then of course you will conclude that it needs
to be changed :-)  But I don't know of any reason to think that the
_erbout design is a failed implementation of an output stream, rather
than a successful implementation of a string buffer.  (It's more than
possible that I'm not familiar with all the past discussions and
statements from the author(s) though.)

In any case, I think the wind-up toy has hit the wall, and I'd like to
turn it around so it can keep moving.  I guess the main thing I'd like
to see, if ERB is to gain a way to do the kind of streaming you're
describing, would be for it to happen without loss: that is, without
loss of consistency (don't just shoehorn the behavior into methods
that already have a clearly defined behavior) and without loss of
functionality (make sure that stringwise template-filling is not
discarded or made difficult).


David

-- 
David A. Black
dblack@wobblini.net