/ 
Text-Template-1.11
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/ Text::Template

NAME

Text::Template - Expand template text with embedded Perl

SYNOPSIS

use Text::Template;

$template = new Text::Template (TYPE => FILE,  SOURCE => 'filename.tmpl');
$template = new Text::Template (TYPE => ARRAY, SOURCE => [ ... ] );
$template = new Text::Template (TYPE => FILEHANDLE, SOURCE => $fh );
$template = new Text::Template (TYPE => STRING, SOURCE => '...' );

$recipient = 'King';
$text = $template->fill_in();  # Replaces `{$recipient}' with `King'
print $text;

$T::recipient = 'Josh';
$text = $template->fill_in(PACKAGE => T);

$hash = { recipient => 'Abed-Nego' };
$text = $template->fill_in(HASH => $hash, ...); # Recipient is Abed-Nego

# Call &callback in case of programming errors in template
$text = $template->fill_in(BROKEN => \&callback, BROKEN_ARG => [...]);

# Evaluate program fragments in Safe compartment with restricted permissions
$text = $template->fill_in(SAFE => $compartment, ...);

# Print result text instead of returning it
$success = $template->fill_in(OUTPUT => \*FILEHANDLE, ...);

use Text::Template 'fill_in_string';
$text = fill_in_string( <<EOM, 'package' => T, ...);
Dear {$recipient},
Pay me at once.
       Love, 
        G.V.
EOM

use Text::Template 'fill_in_file';
$text = fill_in_file($filename, ...);

DESCRIPTION

This is a library for generating form letters, building HTML pages, or filling in templates generally. A `template' is a piece of text that has little Perl programs embedded in it here and there. When you `fill in' a template, you evaluate the little programs and replace them with their values.

Here's an example of a template:

Dear {$title} {$lastname},

It has come to our attention that you are delinquent in your
{$monthname[$last_paid_month]} payment.  Please remit
${sprintf("%.2f", $amount)} immediately, or your patellae may
be needlessly endangered.

		Love,

		Mark "Vizopteryx" Dominus

The result of filling in this template is a string, which might look something like this:

Dear Mr. Gates,

It has come to our attention that you are delinquent in your
February payment.  Please remit
$392.12 immediately, or your patellae may
be needlessly endangered.


		Love,

		Mark "Vizopteryx" Dominus

You can store a template in a file outside your program. People can modify the template without modifying the program. You can separate the formatting details from the main code, and put the formatting parts of the program into the template. That prevents code bloat and encourages functional separation.

Template Syntax

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.

Details

Template Parsing

The Text::Template module scans the template source. An open brace { begins a program fragment, which continues until the matching close brace }. When the template is filled in, the program fragments are evaluated, and each one is replaced with the resulting value to yield the text that is returned.

A backslash \ in front of a brace (or another backslash that is in front of a brace) escapes its special meaning. The result of filling out this template:

\{ The sum of 1 and 2 is {1+2}  \}

is

{ The sum of 1 and 2 is 3  }

If you have an unmatched brace, Text::Template will return a failure code and a warning about where the problem is. Backslashes that do not precede a brace are passed through unchanged. If you have a template like this:

{ "String that ends in a newline.\n" }

The backslash inside the string is passed through to Perl unchanged, so the \n really does turn into a newline. See the note at the end for details about the way backslashes work.

Each program fragment should be a sequence of Perl statements, which are evaluated the usual way. The result of the last statement executed will be evaluted in scalar context; the result of this statement is a string, which is interpolated into the template in place of the program fragment itself.

The fragments are evaluated in order, and side effects from earlier fragments will persist into later fragments:

	{$x = @things; ''}The Lord High Chamberlain has gotten {$x}
	things for me this year.  
	{ $diff = $x - 17; 
	  $more = 'more'
	  if ($diff == 0) {
	    $diff = 'no';
	  } elsif ($diff < 0) {
	    $more = 'fewer';
	  } 
          '';
	} 
	That is {$diff} {$more} than he gave me last year.

The value of $x set in the first line will persist into the next fragment that begins on the third line, and the values of $diff and $more set in the second fragment will persist and be interpolated into the last line. The output will look something like this:

The Lord High Chamberlain has gotten 42
things for me this year.  

That is 35 more than he gave me last year.

That is all the syntax there is.

The $OUT variable

There is one special trick you can play in a template. Here is the motivation for it: Suppose you are going to pass an array, @items, into the template, and you want the template to generate a bulleted list with a header, like this:

Here is a list of the things I have got for you since 1907:
  * Ivory
  * Apes
  * Peacocks
  * ...

One way to do it is with a template like this:

	Here is a list of the things I have got for you since 1907:
	{ my $blist = '';
          foreach $i (@items) {
            $blist .= qq{  * $i\n};
          }    
          $blist;
        }

Here we construct the list in a variable called $blist, which we return at the end. This is a little cumbersome. There is a shortcut.

Inside of templates, there is a special variable called $OUT. Anything you append to this variable will appear in the output of the template. Also, if you use $OUT in a program fragment, the normal behavior, of replacing the fragment with its return value, is disabled; instead the fragment is replaced with the value of $OUT. This means that you can write the template above like this:

	Here is a list of the things I have got for you since 1907:
	{ foreach $i (@items) {
            $OUT .= "  * $i\n";
          }    
        }

$OUT is reinitialized to the empty string at the start of each program fragment. It is private to Text::Template, so you can't use a variable named $OUT in your template without invoking the special behavior.

General Remarks

All Text::Template functions return undef on failure, and set the variable $Text::Template::ERROR to contain an explanation of what went wrong. For example, if you try to create a template from a file that does not exist, $Text::Template::ERROR will contain something like:

Couldn't open file xyz.tmpl: No such file or directory

new

$template = new Text::Template ( TYPE => ..., SOURCE => ... );

This creates and returns a new template object. new returns undef and sets $Text::Template::ERROR if it can't create the template object. SOURCE says where the template source code will come from. TYPE says what kind of objec the source is.

The most common type of source is a file:

new Text::Template ( TYPE => 'FILE', SOURCE => $filename );

This reads the template from the specified file. The filename is opened with the Perl open command, so it can be a pipe or anything else that makes sense with open.

The TYPE can also be STRING, in which case the SOURCE should be a string:

	new Text::Template ( TYPE => 'STRING', 
                             SOURCE => "This is the actual template!" );

The TYPE can be ARRAY, in which case the source should be a reference to an array of strings. The concatenation of these strings is the template:

	new Text::Template ( TYPE => 'ARRAY', 
                             SOURCE => [ "This is ", "the actual", 
                                         " template!",
                                       ]
                           );

The TYPE can be FILEHANDLE, in which case the source should be an open filehandle (such as you got from the FileHandle or IO::* packages, or a glob, or a reference to a glob). In this case Text::Template will read the text from the filehandle up to end-of-file, and that text is the template:

	# Read template source code from STDIN:
	new Text::Template ( TYPE => 'FILEHANDLE', 
                             SOURCE => \*STDIN  );

If you omit the TYPE attribute, it's taken to be FILE. SOURCE is required. If you omit it, the program will abort.

The words TYPE and SOURCE can be spelled any of the following ways:

TYPE	SOURCE
Type	Source
type	source
-TYPE	-SOURCE
-Type	-Source
-type	-source

Pick a style you like and stick with it.

compile

$template->compile()

Loads all the template text from the template's source, parses and compiles it. If successful, returns true; otherwise returns false and sets $Text::Template::ERROR. If the template is already compiled, it returns true and does nothing.

You don't usually need to invoke this function, because fill_in (see below) compiles the template if it isn't compiled already.

fill_in

$template->fill_in(OPTIONS);

Fills in a template. Returns the resulting text if successful. Otherwise, returns undef and sets $Text::Template::ERROR.

The OPTIONS are a hash, or a list of key-value pairs. You can write the key names in any of the six usual styles as above; this means that where this manual says PACKAGE (for example) you can actually use any of

PACKAGE Package package -PACKAGE -Package -package

Pick a style you like and stick with it. The all-lowercase versions may yield spurious warnings about

Ambiguous use of package => resolved to "package"

so you might like to avoid them and use the capitalized versions.

At present, there are six legal options: PACKAGE, BROKEN, BROKEN_ARG, SAFE, HASH, and OUTPUT.

PACKAGE

PACKAGE specifies the name of a package in which the program fragments should be evaluated. The default is to use the package from which fill_in was called. For example, consider this template:

The value of the variable x is {$x}.

If you use $template->fill_in(PACKAGE => 'R') , then the $x in the template is actually replaced with the value of $R::x. If you omit the PACKAGE option, $x will be replaced with the value of the $x variable in the package that actually called fill_in.

You should almost always use PACKAGE. If you don't, and your template makes changes to variables, those changes will be propagated back into the main program. Evaluating the template in a private package helps prevent this. The template can still modify variables in your program if it wants to, but it will have to do so explicitly. See the section at the end on `Security'.

Here's an example of using PACKAGE:

Your Royal Highness,

Enclosed please find a list of things I have gotten
for you since 1907:

{ foreach $item (@items) {
    $OUT .= " * \u$item\n";
  }
}

Signed,
Lord High Chamberlain

We want to pass in an array which will be assigned to the array @items. Here's how to do that:

@items = ('ivory', 'apes', 'peacocks', );
$template->fill_in();

This is not very safe. The reason this isn't as safe is that if you had a variable named $item in scope in your program at the point you called fill_in, its value would be clobbered by the act of filling out the template. The problem is the same as if you had written a subroutine that used those variables in the same waythat the template does. ($OUT is special in templates and is always safe.)

One solution to this is to make the $item variable private to the template by declaring it with my. If the template does this, you are safe.

But if you use the PACKAGE option, you will probably be safe even if the template does not declare its variables with my:

@Q::items = ('ivory', 'apes', 'peacocks', );
$template->fill_in(PACKAGE => 'Q');

In this case the template will clobber the variables $Q::item and $Q::list, which are not related to the ones your program was using.

Templates cannot affect variables in the main program that are declared with my, unless you give the template references to those variables.

HASH

You may not want to put the template variables into a package. Packages can be hard to manage: You can't copy them, for example. HASH provides an alternative.

The value for HASH should be a reference to a hash that maps variable names to values. For example,

$template->fill_in(HASH => { recipient => "The King",
			     items => ['gold', 'frankincense', 'myrrh']
			   });

will fill out the template and use "The King" as the value of $recipient and the list of items as the value of @items.

The full details of how it works are a little involved, so you might want to skip to the next section.

Suppose the key in the hash is key and the value is value.

  • If the value is undef, then any variables named $key, @key, %key, etc., are undefined.

  • If the value is a string or a number, then $key is set to that value in the template.

  • If the value is a reference to an array, then @key is set to that array. If the value is a reference to a hash, then %key is set to that hash. Similarly if value is any other kind of reference. This means that

    var => "foo"

    and

    var => \"foo"

    have almost exactly the same effect. (The difference is that in the former case, the value is copied, and in the latter case it is aliased.)

Normally, the way this works is by allocating a private package, loading all the variables into the package, and then filling out the template as if you had specified that package. A new package is allocated each time. However, if you also use the PACKAGE option, Text::Template loads the variables into the package you specified, and they stay there after the call returns. Subsequent calls to fill_in that use the same package will pick up the values you loaded in.

If the argument of HASH is a reference to an array instead of a reference to a hash, then the array should contain a list of hashes whose contents are loaded into the template package one after the other. You can use this feature if you want to combine several sets of variables. For example, one set of variables might be the defaults for a fill-in form, and the second set might be the user inputs, which override the defaults when they are present:

$template->fill_in(HASH => [\%defaults, \%user_input]);

You can also use this to set two variables with the same name:

	$template->fill_in(HASH => [{ v => "The King" },
                                    { v => [1,2,3] },
	                           ]
                          );

This sets $v to "The King" and @v to (1,2,3).

BROKEN

If any of the program fragments fails to compile or aborts for any reason, and you have set the BROKEN option to a function reference, Text::Template will invoke the function. This function is called the BROKEN function. The BROKEN function will tell Text::Template what to do next.

If the BROKEN function returns undef, Text::Template will immediately abort processing the template and return the text that it has accumulated so far. If your function does this, it should set a flag that you can examine after fill_in returns so that you can tell whether there was a premature return or not.

If the BROKEN function returns any other value, that value will be interpolated into the template as if that value had been the return value of the program fragment to begin with. For example, if the BROKEN function returns an error string, the error string will be interpolated into the output of the template in place of the program fragment that cased the error.

If you don't specify a BROKEN function, Text::Template supplies a default one that returns something like

Program fragment at line 17 delivered error ``Illegal
division by 0''

Since this is interpolated into the template at the place the error occurred, a template like this one:

(3+4)*5 = { 3+4)*5 }

yields this result:

(3+4)*5 = Program fragment at line 1 delivered error
``syntax error''

If you specify a value for the BROKEN attribute, it should be a reference to a function that fill_in can call instead of the default function.

fill_in will pass an associative array to the broken function. The associative array will have at least these three members:

text

The source code of the program fragment that failed

error

The text of the error message ($@) generated by eval

lineno

The line number of the template data at which the program fragment began

There may also be an arg member. See BROKEN_ARG, below

BROKEN_ARG

If you supply the BROKEN_ARG option to fill_in, the value of the option is passed to the BROKEN function whenever it is called. The default BROKEN function ignores the BROKEN_ARG, but you can write a custom BROKEN function that uses the BROKEN_ARG to get more information about what went wrong.

The BROKEN function could also use the BROKEN_ARG as a reference to store an error message or some other information that it wants to communicate back to the caller. For example:

$error = '';

sub my_broken {	
   my %args = @_;
   my $err_ref = $args{arg};
   ...
   $$err_ref = "Some error message";
   return undef;
}

$template->fill_in(BROKEN => \&my_broken,
		   BROKEN_ARG => \$error,
		  );

if ($error) {
  die "It didn't work: $error";
}

If one of the program fragments in the template fails, it will call the BROKEN function, my_broken, and pass it the BROKEN_ARG, which is a reference to $error. my_broken can store an error message into $error this way. Then the function that called fill_in can see if my_broken has left an error message for it to find, and proceed accordingly.

SAFE

If you give fill_in a SAFE option, its value should be a safe compartment object from the Safe package. All evaluation of program fragments will be performed in this compartment. See Safe for full details about such compartments and how to restrict the operations that can be performed in them.

If you use the PACKAGE option with SAFE, the package you specify will be placed into the safe compartment and evaluation will take place in that package as usual.

If not, SAFE operation is a little different from the default. Usually, if you don't specify a package, evaluation of program fragments occurs in the package from which the template was invoked. But in SAFE mode the evaluation occurs inside the safe compartment and cannot affect the calling package. Normally, if you use HASH without PACKAGE, the hash variables are imported into a private, one-use-only package. But if you use HASH and SAFE together without PACKAGE, the hash variables will just be loaded into the root namespace of the Safe compartment.

OUTPUT

If your template is going to generate a lot of text that you are just going to print out again anyway, you can save memory by having Text::Template print out the text as it is generated instead of making it into a big string and returning the string. If you supply the OUTPUT option to fill_in, the value should be a filehandle. The generated text will be printed to this filehandle as it is constructed. For example:

$template->fill_in(OUTPUT => \*STDOUT, ...);

fills in the $template as usual, but the results are immediately printed to STDOUT. This may result in the output appearing more quickly than it would have otherwise.

If you use OUTPUT, the return value from fill_in is still true on success and false on failure, but the complete text is not returned to the caller.

Convenience Functions

fill_this_in

The basic way to fill in a template is to create a template object and then call fill_in on it. This is useful if you want to fill in the same template more than once.

In some programs, this can be cumbersome. fill_this_in accepts a string, which contains the template, and a list of options, which are passed to fill_in as above. It constructs the template object for you, fills it in as specified, and returns the results. It returns undef and sets $Text::Template::ERROR if it couldn't generate any results.

An example:

$Q::name = 'Donald';
$Q::amount = 141.61;
$Q::part = 'hyoid bone';

$text = Text::Template->fill_this_in( <<EOM, PACKAGE => Q);
Dear {\$name},
You owe me \${sprintf('%.2f', \$amount)}.  
Pay or I will break your {\$part}.
	Love,
	Grand Vizopteryx of Irkutsk.
EOM

Notice how we included the template in-line in the program by using a `here document' with the << notation.

fill_this_in is a deprecated feature. It is only here for backwards compatibility, and may be removed in some far-future version in Text::Template. You should use fill_in_string instead. It is described in the next section.

fill_in_string

It is stupid that fill_this_in is a class method. It should have been just an imported function, so that you could omit the Text::Template-> in the example above. But I made the mistake four years ago and it is too late to change it.

fill_in_string is exactly like fill_this_in except that it is not a method and you can omit the Text::Template-> and just say

print fill_in_string(<<EOM, ...);
Dear {$name},
  ...
EOM

To use fill_in_string, you need to say

use Text::Template 'fill_in_string';

at the top of your program. You should probably use fill_in_string instead of fill_this_in.

fill_in_file

If you import fill_in_file, you can say

$text = fill_in_file(filename, ...);

The ... are passed to fill_in as above. The filename is the name of the file that contains the template you want to fill in. It returns the result text. or undef, as usual.

If you are going to fill in the same file more than once in the same program you should use the longer new / fill_in sequence instead. It will be a lot faster because it only has to read and parse the file once.

Including files into templates

People always ask for this. ``Why don't you have an include function?'' they want to know. The short answer is this is Perl, and Perl already has an include function. If you want it, you can just put

{qx{cat filename}}

into your template. Voilà.

If you don't want to use cat, you can write a little four-line function that opens a file and dumps out its contents, and call it from the template. I wrote one for you. In the template, you can say

{Text::Template::_load_text(filename)}

If that is too verbose, here is a trick. Suppose the template package that you are going to be mentioning in the fill_in call is package Q. Then in the main program, write

*Q::include = \&Text::Template::_load_text;

This imports the _load_text function into package Q with the name include. From then on, any template that you fill in with package Q can say

{include(filename)}

to insert the text from the named file at that point. If you are using the HASH option instead, just put include => \&Text::Template::_load_text into the hash instead of importing it explicitly.

Suppose you don't want to insert a plain text file, but rather you want to include one template within another? Just use fill_in_file in the template itself:

{Text::Template::fill_in_file(filename)}

You can do the same importing trick if this is too much to type.

Miscellaneous

my variables

People are frequently surprised when this doesn't work:

my $recipient = 'The King';
my $text = fill_in_file('formletter.tmpl');

The text The King doesn't get into the form letter. Why not? Because $recipient is a my variable, and the whole point of my variables is that they're private and inaccessible except in the scope in which they're declared. The template is not part of that scope, so the template can't see $recipient.

If that's not the behavior you want, don't use my. my means a proivate variable, and in this case you don't want the variable to be private. Put the variables into package variables in some other package, and use the PACKAGE option to fill_in, or pass the names and values in a hash with the HASH option.

Security Matters

All variables are evaluated in the package you specify with the PACKAGE option of fill_in. if you use this option, and if your templates don't do anything egregiously stupid, you won't have to worry that evaluation of the little programs will creep out into the rest of your program and wreck something.

Nevertheless, there's really no way (except with Safe) to protect against a template that says

{ $Important::Secret::Security::Enable = 0; 
  # Disable security checks in this program 
}

or

{ $/ = "ho ho ho";   # Sabotage future uses of <FH>.
  # $/ is always a global variable
}

or even

{ system("rm -rf /") }

so don't go filling in templates unless you're sure you know what's in them. If you're worried, or you can't trust the person who wrote the template, use the SAFE option.

A final warning: program fragments run a small risk of accidentally clobbering local variables in the fill_in function itself. These variables all have names that begin with $fi_, so if you stay away from those names you'll be safe. (Of course, if you're a real wizard you can tamper with them deliberately for exciting effects; this is actually how $OUT works.) I can fix this, but it will make the package slower to do it, so I would prefer not to.

JavaScript

Jennifer D. St Clair asks:

	> Most of my pages contain JavaScript and Stylesheets.
        > How do I change the template identifier?

Jennifer is worried about the braces in the JavaScript being taken as the delimiters of the Perl program fragments. Of course, disaster will ensue when perl tries to evaluate these as if they were Perl programs.

I didn't provide a facility for changing the braces to something else, because it complicates the parsing, and in my experience it isn't necessary. There are two easy solutions:

1. You can put \ in front of {, }, or \ to remove its special meaning. So, for example, instead of

    if (br== "n3") { 
	// etc.
    }

you can put

    if (br== "n3") \{ 
	// etc.
    \}

and it'll come out of the template engine the way you want.

But here is another method that is probably better. To see how it works, first consider what happens if you put this into a template:

{ 'foo' }

Since it's in braces, it gets evaluated, and obviously, this is going to turn into

foo

So now here's the trick: In Perl, q{...} is the same as '...'. So if we wrote

{q{foo}}

it would turn into

foo

So for your JavaScript, just write

  {q{
    if (br== "n3") { 
	  // etc.
    }
  }

and it'll come out as

    if (br== "n3") { 
	  // etc.
    }

which is what you want.

This trick is so easy that I thought didn't need to put in the feature that lets you change the bracket characters to something else.

Shut Up!

People sometimes try to put an initialization section at the top of their templates, like this:

{ ...
  $var = 17;
}

Then they complain because there is a 17 at the top of the output that they didn't want to have there.

Remember that a program fragment is replaced with its own return value, and that in Perl the return value of a code block is the value of the last expression that was evaluated, which in this case is 17. If it didn't do that, you wouldn't be able to write {$recipient} and have the recipient filled in.

To prevent the 17 from appearing in the output is very simple:

{ ...
  $var = 17;
  '';
}

Now the last expression evaluated yields the empty string, which is invisible.

Compatibility

Every effort has been made to make this module compatible with older versions. There are three exceptions. One is the output format of the default BROKEN subroutine; I decided that the old format was too verbose. If this bothers you, it's easy to supply a custom subroutine that yields the old behavior. The second is that the $OUT feature arrogates the $OUT variable for itself. If you had templates that happened to use a variable named $OUT, you will have to change them to use some other variable or all sorts of strangeness may result.

The third incompatibility is with the behavior of the \ metacharacter. In 0.1b, \\ was special everywhere, and the template processor always replaced it with a single backslash before passing the code to Perl for evaluation. The rule now is more complicated but probably more convenient. See the section on backslash processing, below, for a full discussion.

With a minor change to fix the format of the default BROKEN subroutine, this version passes the test suite from the old version. (It is in t/01-basic.t.) The old test suite was too small, but it's a little reassuring.

Backslash Processing

In Text::Template beta versions, the backslash was special whenever it appeared before a brace or another backslash. That meant that while {"\n"} did indeed generate a newline, {"\\"} did not generate a backslash, because the code passed to Perl for evaluation was "\" which is a syntax error. If you wanted a backslash, you would have had to write {"\\\\"}.

In Text::Template versions 1.0 through 1.10, there was a bug: Backslash was special everywhere. In these versions, {"\n"} generated the letter n.

The bug has been corrected in version 1.11, but I did not go back to exactly the old rule, because I did not like the idea of having to write {"\\\\"} to get one backslash. The rule is now more complicated to remember, but probably easier to use. The rule is now: Backslashes are always passed to Perl unchanged unless they occur as part of a sequence like \\\...\\\{ or \\\...\\\}. In these contexts, they are special; \\ is replaced with \, and \{ and \} signal a literal brace.

Examples:

\{ foo \}

is not evaluated, because the \ before the rbaces signals that they should be taken literally. The result in the output looks like this:

{ foo }

This is a syntax error:

{ "foo}" }

because Text::Template things that the code ends at the first }, and then gets upset when it sees the second one. TO make this work correctly, use

{ "foo\}" }

This passes "foo}" to Perl for evaluation. Note there's no \ in the evaluated code. If you really want a \ in the evaluated code, use

{ "foo\\\}" }

This passes "foo\}" to Perl for evaluation.

A short note about $Text::Template::ERROR

In the past some people have fretted about `violating the package boundary' by examining a variable inside the Text::Template package. Don't feel this way. $Text::Template::ERROR is part of the published, official interface to this package. It is perfectly OK to inspect this variable. The interface is not going to change.

If it really, really bothers you, you can import a function called TTerror that returns the current value of the $ERROR variable. So you can say:

use Text::Template 'TTerror';

my $template = new Text::Template (SOURCE => $filename);
unless ($template) {
  my $err = TTerror;
  die "Couldn't make template: $err; aborting";
}

I don't see what benefit this has over just doing this:

use Text::Template;

my $template = new Text::Template (SOURCE => $filename)
  or die "Couldn't make template: $Text::Template::ERROR; aborting";

But if it makes you happy to do it that way, go ahead.

Sticky Widgets in Template Files

The CGI module provides functions for `sticky widgets', which are form input controls that retain their values from one page to the next. Sometimes people want to know how to include these widgets into their template output.

It's totally straightforward. Just call the CGI functions from inside the template:

{ $q->checkbox_group(NAME => 'toppings',
	  	     LINEBREAK => true,
		     COLUMNS => 3,
		     VALUES => \@toppings],
		    );
}

Author

Mark-Jason Dominus, Plover Systems

mjd-perl-template@pobox.com

You can join a very low-volume (<10 messages per year) mailing list for announcements about this package. Send an empty note to mjd-perl-template-request@plover.com to join.

For updates, visit http://www.plover.com/~mjd/perl/Template/.

Support?

This software is version 1.0. It is a complete rewrite of an older package, and may have bugs. Suggestions and bug reports are always welcome. Send them to mjd-perl-template@plover.com. (That is my address, not the address of the mailing list. The mailing list address is a secret.)

Thanks

Many thanks to the following people for offering support, encouragement, advice, and all the other good stuff.

Klaus Arnhold / Mike Brodhead / Tom Brown / Tim Bunce / Juan E. Camacho / Joseph Cheek / San Deng / Bob Dougherty / Dan Franklin / Todd A. Green / Michelangelo Grigni / Tom Henry / Matt X. Hunter / Robert M. Ioffe / Daniel LaLiberte / Reuven M. Lerner / Joel Meulenberg / Jason Moore / Bek Oberin / Ron Pero / Hans Persson / Jonathan Roy / Shabbir J. Safdar / Jennifer D. St Clair / Uwe Schneider / Randal L. Schwartz / Michael G Schwern / Brian C. Shensky / Niklas Skoglund / Tom Snee / Hans Stoop / Michael J. Suzio / Dennis Taylor / James H. Thompson / Shad Todd / Larry Virden / Andy Wardley / Matt Womer / Andrew G Wood / Michaely Yeung

Special thanks to:

Jonathan Roy

for telling me how to do the Safe support (I spent two years worrying about it, and then Jonathan pointed out that it was trivial.)

Ranjit Bhatnagar

for demanding less verbose fragments like they have in ASP, for helping me figure out the Right Thing, and, especially, for talking me out of adding any new syntax. These discussions resulted in the $OUT feature.

Shabbir J. Safdar

for volunteering to maintain a slightly modified version of Text::Template which will run under perl.5003 and other early versions.

Bugs and Caveats

my variables in fill_in are still susceptible to being clobbered by template evaluation. They all begin with fi_, so avoid those names in your templates.

The line number information will be wrong if the template's lines are not terminated by "\n". You should let me know if this is a problem. If you do, I will fix it.

The default format for reporting of broken program fragments has changed since version 0.1.

The $OUT variable has a special meaning in templates, so you cannot use it as if it were a regular variable.

There are not quite enough tests in the test suite.