Thread: [htmltmpl] Nested templates
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From: Brad B. <bm...@ma...> - 2009-11-25 02:24:56
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Hi all,
I once tried to implement nested templates with HTML::Template.
Below is an example of what I came up with:
1 #!/usr/local/bin/perl
2
3 use strict;
4 use warnings;
5 use HTML::Template;
6
7 my $text = <<__;
8 This is a <TMPL_VAR NAME="color"> bird.
9 This is a <TMPL_VAR NAME="<TMPL_VAR NAME="color">"> bird.
10 This is a <TMPL_VAR NAME="<TMPL_VAR NAME="<TMPL_VAR
NAME="color">">"> bird.
11 __
12
13 my $output = '';
14 my $sref = \$text;
15 my $count;
16
17 while (1) {
18 $count++;
19
20 my $tmpl = HTML::Template->new(
21 scalarref => $sref,
22 strict => 0,
23 die_on_bad_params => 0,
24 case_sensitive => 1,
25 );
26
27 $tmpl->param( color => 'blue' );
28 $tmpl->param( blue => 'BLUE' );
29 $tmpl->param( BLUE => '**BLUE**' );
30
31 $text = $tmpl->output();
32
33 print "\n$count:\n$text"; # debug
34
35 last if $output eq $text; # no changes since last time
36 $output = $text;
37
38 }
39
40 print "\nfinal: \n$output";
41
42 __END__
1:
This is a blue bird.
This is a <TMPL_VAR NAME="blue"> bird.
This is a <TMPL_VAR NAME="<TMPL_VAR NAME="blue">"> bird.
2:
This is a blue bird.
This is a BLUE bird.
This is a <TMPL_VAR NAME="BLUE"> bird.
3:
This is a blue bird.
This is a BLUE bird.
This is a **BLUE** bird.
4:
This is a blue bird.
This is a BLUE bird.
This is a **BLUE** bird.
final:
This is a blue bird.
This is a BLUE bird.
This is a **BLUE** bird.
I would like a better way of doing this. The calls to
new() on line 20, the copies on lines 31 and 36, and
the compares on line 36 just seem all a bit much for
what ought (I think) to be more like
1 while s/from/to/g;
Is there a better way?
Apologies if this has been beat to death in the past ...
Regards,
Brad
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From: Mathew R. <mat...@ne...> - 2009-11-25 03:15:34
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<snip>
that seems somewhat complicated - you could use a regex in the while
loop, as in:
while ($text =~ /<TMPL_/) { ... }
instead of using a loop variable or breaking out of the loop. In
particular it would save you having to do any string comparisons and
would avoid the extra loop iteration.
Mathew Robertson
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From: Michael P. <mp...@pl...> - 2009-11-25 14:34:31
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On 11/24/2009 09:24 PM, Brad Baxter wrote:
> Is there a better way?
I've done this by using a different name for each pass. So something like:
<pass2_var name="<tmpl_var name=foo>">
So you run it through HTML::Template once to get the output and then
s/<pass2_/<tmpl_/gi;
And then run it again.
--
Michael Peters
Plus Three, LP
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From: Alex T. <al...@ac...> - 2009-11-25 15:58:22
|
On Tue, 24 Nov 2009 21:24:30 -0500, Brad Baxter wrote
> Hi all,
>
> I once tried to implement nested templates with HTML::Template.
> Below is an example of what I came up with:
>
> 1 #!/usr/local/bin/perl
> 2
> 3 use strict;
> 4 use warnings;
> 5 use HTML::Template;
> 6
> 7 my $text = <<__;
> 8 This is a <TMPL_VAR NAME="color"> bird.
> 9 This is a <TMPL_VAR NAME="<TMPL_VAR NAME="color">"> bird.
> 10 This is a <TMPL_VAR NAME="<TMPL_VAR NAME="<TMPL_VAR
> NAME="color">">"> bird.
> 11 __
> 12
> 13 my $output = '';
> 14 my $sref = \$text;
> 15 my $count;
> 16
> 17 while (1) {
> 18 $count++;
> 19
> 20 my $tmpl = HTML::Template->new(
> 21 scalarref => $sref,
> 22 strict => 0,
> 23 die_on_bad_params => 0,
> 24 case_sensitive => 1,
> 25 );
> 26
> 27 $tmpl->param( color => 'blue' );
> 28 $tmpl->param( blue => 'BLUE' );
> 29 $tmpl->param( BLUE => '**BLUE**' );
> 30
> 31 $text = $tmpl->output();
> 32
> 33 print "\n$count:\n$text"; # debug
> 34
> 35 last if $output eq $text; # no changes since last time
> 36 $output = $text;
> 37
> 38 }
> 39
> 40 print "\nfinal: \n$output";
> 41
> 42 __END__
>
> 1:
> This is a blue bird.
> This is a <TMPL_VAR NAME="blue"> bird.
> This is a <TMPL_VAR NAME="<TMPL_VAR NAME="blue">"> bird.
>
> 2:
> This is a blue bird.
> This is a BLUE bird.
> This is a <TMPL_VAR NAME="BLUE"> bird.
>
> 3:
> This is a blue bird.
> This is a BLUE bird.
> This is a **BLUE** bird.
>
> 4:
> This is a blue bird.
> This is a BLUE bird.
> This is a **BLUE** bird.
>
> final:
> This is a blue bird.
> This is a BLUE bird.
> This is a **BLUE** bird.
>
> I would like a better way of doing this. The calls to
> new() on line 20, the copies on lines 31 and 36, and
> the compares on line 36 just seem all a bit much for
> what ought (I think) to be more like
>
> 1 while s/from/to/g;
>
> Is there a better way?
I would just do:
#!/usr/local/bin/perl
use strict;
use warnings;
use HTML::Template;
my $template = qq|
This is a <tmpl_var color> bird.
This is a <tmpl_if is_blue>BLUE</tmpl_if> bird.
This is a <tmpl_if is_blue>**BLUE**</tmpl_if> bird.
|;
# all the logic of what the color will be goes here
my $color = 'blue';
my $tmpl = HTML::Template->new(
scalarref => \$template,
strict => 0,
die_on_bad_params => 0,
case_sensitive => 1,
);
$tmpl->param(
color => $color,
is_blue => $color eq 'blue' ? 1 : 0,
);
print $tmpl->output();
So many advantages. The logic is completely separate from the presentation. If you send the template
to a speaker of a different language, they can localize that with no problems. The code is much
shorter at 29 lines vs. 42 lines, and its much more clear to a future maintainer what is happening
without any brain gymnastics.
HTH,
Alex
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From: Brad B. <bm...@ma...> - 2009-11-30 16:55:19
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Yes, that solves a slightly different problem than my (admittedly somewhat pointless) example, but it doesn't address the nesting that I'm after. I don't do it a lot, but there are key points where I want to, and I like to be able to count on it working. I'd like there to be an option to new() that says, "Do repeated substitutions until there aren't any more". I suspect that would still incur a 'compile' step each time, but I'd hope it could avoid the copy from output() and the repeated param() calls. Thanks, Brad On Wed, Nov 25, 2009 at 10:58 AM, Alex Teslik <al...@ac...> wrote: > On Tue, 24 Nov 2009 21:24:30 -0500, Brad Baxter wrote >> >> Is there a better way? > > I would just do: > > #!/usr/local/bin/perl > > use strict; > use warnings; > use HTML::Template; > > my $template = qq| > This is a <tmpl_var color> bird. > This is a <tmpl_if is_blue>BLUE</tmpl_if> bird. > This is a <tmpl_if is_blue>**BLUE**</tmpl_if> bird. > |; > > # all the logic of what the color will be goes here > my $color = 'blue'; > > my $tmpl = HTML::Template->new( > scalarref => \$template, > strict => 0, > die_on_bad_params => 0, > case_sensitive => 1, > ); > > $tmpl->param( > color => $color, > is_blue => $color eq 'blue' ? 1 : 0, > ); > > print $tmpl->output(); > > So many advantages. The logic is completely separate from the presentation. If you send the template > to a speaker of a different language, they can localize that with no problems. The code is much > shorter at 29 lines vs. 42 lines, and its much more clear to a future maintainer what is happening > without any brain gymnastics. > > HTH, > Alex > -- Brad Baxter ---------------------------------------------------------------------- |
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From: Brad B. <bm...@ma...> - 2009-11-30 16:42:15
|
Yes, that's better. It replaces a copy and compare (and
extra loop) as you say with a regx match. I still have
a copy, object creation, and repeated param settings that
bother me, but I suspect this is the best I'm going to get
without a significant change to H::T.
Thanks,
Brad
On Tue, Nov 24, 2009 at 9:48 PM, Mathew Robertson
<mat...@ne...> wrote:
> <snip>
>
> that seems somewhat complicated - you could use a regex in the while loop,
> as in:
>
> while ($text =~ /<TMPL_/) { ... }
>
> instead of using a loop variable or breaking out of the loop. In particular
> it would save you having to do any string comparisons and would avoid the
> extra loop iteration.
>
> Mathew Robertson
>
>
--
Brad Baxter
----------------------------------------------------------------------
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From: Brad B. <bm...@ma...> - 2009-11-30 19:45:00
|
FWIW, below is my final version of code to fill
in nested templates. It's down to a call to new()
and a call to output() in each loop (besides the
pattern match).
Of course, there's a hidden param operation via
the assoc object. Whether or not this benchmarks
better, I don't know, but it comes across as
simpler IMO.
Of course, it introduces a bit of a dummy class
for the associate option, but I don't mind that
too much.
Thanks all,
Brad
1 #!/usr/local/bin/perl
2
3 use strict;
4 use warnings;
5 use HTML::Template;
6
7 my $assoc = My::Param->new(
8 { color => 'blue', blue => 'BLUE', BLUE => '**BLUE**' }
9 );
10
11 my $text = <<__;
12 This is a <TMPL_VAR NAME="color"> bird.
13 This is a <TMPL_VAR NAME="<TMPL_VAR NAME="color">"> bird.
14 This is a <TMPL_VAR NAME="<TMPL_VAR NAME="<TMPL_VAR
NAME="color">">"> bird.
15 __
16
17 my $sref = \$text;
18 my $count;
19
20 while ( $text =~ /<TMPL_/i ) {
21
22 my $tmpl = HTML::Template->new(
23 scalarref => $sref,
24 strict => 0,
25 case_sensitive => 1,
26 associate => $assoc,
27 );
28
29 $text = $tmpl->output();
30
31 print "\n".++$count.":\n$text"; # debug
32 }
33
34 print "\nfinal: \n$text";
35
36 package My::Param;
37 sub new { bless $_[1], $_[0] }
38 sub param { my $self = shift;
39 return keys %$self if wantarray;
40 return $self->{ $_[0] } }
41
42 __END__
1:
This is a blue bird.
This is a <TMPL_VAR NAME="blue"> bird.
This is a <TMPL_VAR NAME="<TMPL_VAR NAME="blue">"> bird.
2:
This is a blue bird.
This is a BLUE bird.
This is a <TMPL_VAR NAME="BLUE"> bird.
3:
This is a blue bird.
This is a BLUE bird.
This is a **BLUE** bird.
final:
This is a blue bird.
This is a BLUE bird.
This is a **BLUE** bird.
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