Brett> This is, however, off of the point I was shooting for. I
Brett> know there will be philisophical differences. I'm mainly
Brett> interested in functional differences. What does Toolkit
Brett> do that Text::Template doesn't?
Perrin> It doesn't look like you got all of your questions answered.
Perrin> Listing all the features Template provides that Text::Template
Perrin> doesn't would take a long time since it's a very full-featured
Perrin> system, but here are some highlights:
Perrin> [snip]
An excellent list.
My $0.02 is the following. At the risk of making statements about
Text::Template based only on a short perusal of the documentation
and writing a couple of short examples, here's a key difference:
TT allows you to capture and manipulate text between directives,
whereas I don't see that Text::Template can. For example, I can't
see that Text::Template can use loops or conditionals around blocks
of text, as in this ePerl example from Perrin:
Perrin> <: if ($product->isbn) { :>
Perrin> It's a book!
Perrin> <: } else { :>
Perrin> It's NOT a book!
Perrin> <: } :>
It appears that in Text::Template each perl fragment must be atomic
(ie: can be separately eval'ed) so you can't have loops or conditionals
spanning across fragments. I can't see any way to manipulate the text
in between the perl fragments.
The philosophy section in the Text::Template pod certainly resonates
with me:
> Philosophy
>
> When people make a template module like this one, they
> almost always start by inventing a special syntax for
> substitutions. For example, they build it so that a string
> like `%%VAR%%' is replaced with the value of `$VAR'. Then
> they realize the need extra formatting, so they put in some
> special syntax for formatting. Then they need a loop, so
> they invent a loop syntax. Pretty soon they have a new
> little template language.
>
> This approach has two problems: First, their little language
> is crippled. If you need to do something the author hasn't
> thought of, you lose. Second: Who wants to learn another
> language? You already know Perl, so why not use it?
>
> `Text::Template' templates are programmed in Perl. You
> embed Perl code in your template, with `{' at the beginning
> and `}' at the end. If you want a variable interpolated,
> you write it the way you would in Perl. If you need to make
> a loop, you can use any of the Perl loop constructions. All
> the Perl built-in functions are available.
However, I find that TT is a big help in balancing the partitioning
of presentation logic and application logic, and its flexibility and
extensibility more than make up for the disadvantage of a (simple)
new language.
All of these different systems (TT, Text::Template, HTML::Template,
HTML::Mason, embPerl, ePerl etc) all represent different tradeoffs
between power, flexibility, partitioning etc. Providing more power
(eg: full perl) also presents a bigger burden in providing a clean,
maintainable template API. There is certainly no universal correct
answer, but TT is the best for our uses.
Craig
