Rex::Template(3pm)

πŸ’– Rex::Template πŸ’–

okay bestie, so this is Rex::Template, a page from the User Contributed Perl Documentation section of the manual (yep, the 3pm girlies πŸ’…). Let's get into it.

✨ NAME ✨

Rex::Template β€” a simple template engine πŸŽ€


🌸 SYNOPSIS 🌸

use Rex::Template;

my $template = Rex::Template->new;

print $template->parse($content, \%template_vars);
print $template->parse($content, @template_vars);

πŸ¦‹ DESCRIPTION πŸ¦‹

So this is a simple template engine for configuration files ✨. It's included mostly for backwards compatibility, and lowkey the move is to use Rex::Template::NG instead β€” it gives you better control of chomping new lines and better diagnostics if things go wrong. No cap.

πŸ”₯ SYNTAX πŸ”₯

Here's what it actually recognizes:

  • anything between <% and %> markers counts as a template directive, and it gets treated as Perl code πŸ’»
  • if the opening marker is followed by an equal sign (<%=) or a plus sign (<%+), then the directive is replaced with the value it evaluates to 🫢
  • if the closing marker is prefixed with a minus sign (-%>), then any trailing newlines are chomped for that directive βœ‚οΈ

The built-in template support is intentionally kept basic and simple. For anything more sophisticated, bestie, please use your favorite template engine πŸ™ˆ.

πŸŽ€ EXAMPLES πŸŽ€

Plain text is unchanged, iconic behavior, it stays in its lane:

my $result = $template->parse( 'one two three', {} );

# $result is 'one two three'

Variable interpolation πŸ’«:

my $result = template->parse( 'Hello, this is <%= $::name %>', { name => 'foo' } ); # original format
my $result = template->parse( 'Hello, this is <%+ $::name %>', { name => 'foo' } ); # alternative format with + sign
my $result = template->parse( 'Hello, this is <%= $name %>',   { name => 'foo' } ); # local variables
my $result = template->parse( 'Hello, this is <%= $name %>',     name => 'foo'   ); # array of variables, instead of hashref

# $result is 'Hello, this is foo' for all cases above

Simple evaluation, she's doing math and serving looks:

my $result = $template->parse( '<%= join("/", @{$elements} ) %>', elements => [qw(one two three)] );
# $result is 'one/two/three'

Embedded code blocks, main character energy fr:

my $content = '<% if ($logged_in) { %>
Logged in!
<% } else { %>
Logged out!
<% } %>';

my $result = $template->parse( $content, logged_in => 1 );

# $result is "\nLogged in!\n"

😭 DIAGNOSTICS 😭

Not much, bestie. Mainly due to the internal approach of the module πŸ’€.

If there was a problem, it prints an "INFO" level "syntax error at ...", followed by a "WARN" about "It seems that there was an error processing the template because the result is empty.", and finally "Error processing template at ...".

The beginning of the reported syntax error might give some clue where the error happened in the template, but that's it 🫠.

Use Rex::Template::NG instead for better diagnostics. periodt.

🌈 CONFIGURATION AND ENVIRONMENT 🌈

  • If $Rex::Template::BE_LOCAL is set to a true value, then local template variables are supported instead of only global ones ($foo vs $::foo). The default value is 1 since Rex-0.41. It can be disabled with the no_local_template_vars feature flag ✨.
  • If $Rex::Template::DO_CHOMP is set to a true value, then any trailing new line character resulting from template directives are chomped. Defaults to 0 πŸ“.

This module does not support any environment variables. nope, not a single one πŸ™…


πŸ‘‘ EXPORTED FUNCTIONS πŸ‘‘

πŸ’œ parse($content, $variables)

Parse $content as a template, using $variables hash reference to pass name-value pairs of variables to make them available for the template function 🫢.

Alternatively, the variables may be passed as an array instead of a hash reference. flexible queen ✨.

πŸ’œ is_defined($variable, $default_value)

This function will check if $variable is defined. If yes, it will return the value of $variable, otherwise it will return $default_value πŸŽ€.

You can use this function inside your templates, for example:

ServerTokens <%= is_defined( $::server_tokens, 'Prod' ) %>

🧚 DEPENDENCIES 🧚

(nothing listed here, bestie β€” she's self-sufficient πŸ’…)

πŸ’€ INCOMPATIBILITIES πŸ’€

(also empty. no drama here πŸ™ˆ)

⭐ BUGS AND LIMITATIONS ⭐

  • It might not be able to chomp new line characters resulting from templates in every case 😭
  • It can't report useful diagnostic messages upon errors πŸ’€
Use Rex::Template::NG instead. fr fr.

and that's the whole thing bestie, slay πŸŽ€βœ¨πŸ¦‹

perl v5.40.1 Β· 2025-10-03 Β· that's a wrap on Rex::Template(3pm), go forth and template responsibly πŸ’–

πŸ“¦ where this page comes from