NAME¶
Template::Alloy - TT2/3, HT, HTE, Tmpl, and Velocity Engine
SYNOPSIS¶
my $t = Template::Alloy->new(
INCLUDE_PATH => ['/path/to/templates'],
);
my $swap = {
key1 => 'val1',
key2 => 'val2',
code => sub { 42 },
hash => {a => 'b'},
};
# print to STDOUT
$t->process('my/template.tt', $swap)
|| die $t->error;
# process into a variable
my $out = '';
$t->process('my/template.tt', $swap, \$out);
### Alloy uses the same syntax and configuration as Template::Toolkit
HTML::Template::Expr style usage¶
my $t = Template::Alloy->new(
filename => 'my/template.ht',
path => ['/path/to/templates'],
);
my $swap = {
key1 => 'val1',
key2 => 'val2',
code => sub { 42 },
hash => {a => 'b'},
};
$t->param($swap);
# print to STDOUT (errors die)
$t->output(print_to => \*STDOUT);
# process into a variable
my $out = $t->output;
### Alloy can also use the same syntax and configuration as HTML::Template
Text::Tmpl style usage¶
my $t = Template::Alloy->new;
my $swap = {
key1 => 'val1',
key2 => 'val2',
code => sub { 42 },
hash => {a => 'b'},
};
$t->set_delimiters('#[', ']#');
$t->set_strip(0);
$t->set_values($swap);
$t->set_dir('/path/to/templates');
my $out = $t->parse_file('my/template.tmpl');
my $str = "Foo #[echo $key1]# Bar";
my $out = $t->parse_string($str);
### Alloy uses the same syntax and configuration as Text::Tmpl
Velocity (VTL) style usage¶
my $t = Template::Alloy->new;
my $swap = {
key1 => 'val1',
key2 => 'val2',
code => sub { 42 },
hash => {a => 'b'},
};
my $out = $t->merge('my/template.vtl', $swap);
my $str = "#set($foo 1 + 3) ($foo) ($bar) ($!baz)";
my $out = $t->merge(\$str, $swap);
DESCRIPTION¶
"An alloy is a homogeneous mixture of two or more elements"
(
http://en.wikipedia.org/wiki/Alloy).
Template::Alloy represents the mixing of features and capabilities from all of
the major mini-language based template systems (support for non-mini-language
based systems will happen eventually). With Template::Alloy you can use your
favorite template interface and syntax and get features from each of the other
major template systems. And Template::Alloy is fast - whether your using
mod_perl, cgi, or running from the commandline. There is even
Template::Alloy::XS for getting a little more speed when that is necessary.
Template::Alloy happened by accident (accidentally on purpose). The
Template::Alloy (Alloy hereafter) was originally a part of the CGI::Ex suite
that performed simple variable interpolation. It used TT2 style variables in
TT2 style tags "[% foo.bar %]". That was all the original
Template::Alloy did. This was fine and dandy for a couple of years. In winter
of 2005-2006 Alloy was revamped to add a few features. One thing led to
another and soon Alloy provided for most of the features of TT2 as well as
some from TT3. Template::Alloy now provides a full-featured implementation of
the Template::Toolkit language.
After a move to a new company that was using HTML::Template::Expr and Text::Tmpl
templates, support was investigated and interfaces for HTML::Template,
HTML::Template::Expr, Text::Tmpl, and Velocity (VTL) were added. All of the
various engines offer the same features - just using different syntaxes and
interfaces.
Template::Toolkit brought the most to the table. HTML::Template brought the LOOP
directive. HTML::Template::Expr brough more vmethods and using vmethods as top
level functions. Text::Tmpl brought the COMMENT directive and encouraged speed
matching (Text::Tmpl is almost entirely C based and is very fast). The
Velocity engine brought AUTO_EVAL and SHOW_UNDEFINED_INTERP.
Most of the standard Template::Toolkit documentation covering directives,
variables, configuration, plugins, filters, syntax, and vmethods should apply
to Alloy just fine (This pod tries to explain everything - but there is too
much). See Template::Alloy::TT for a listing of the differences between Alloy
and TT.
Most of the standard HTML::Template and HTML::Template::Expr documentation
covering methods, variables, expressions, and syntax will apply to Alloy just
fine as well.
Most of the standard Text::Tmpl documentation applies, as does the documentation
covering Velocity (VTL).
So should you use Template::Alloy ? Well, try it out. It may give you no visible
improvement. Or it could.
BACKEND¶
Template::Alloy uses a recursive regex based grammar (early versions during the
CGI::Ex::Template phase did not). This allows for the embedding of opening and
closing tags inside other tags (as in [% a = "[% 1 + 2 %]" ; a|eval
%]). The individual methods such as parse_expr and play_expr may be used by
external applications to add TT style variable parsing to other applications.
The regex parser returns an AST (abstract syntax tree) of the text, directives,
variables, and expressions. All of the different template syntaxes compile to
the same AST format. The AST is composed only of scalars and arrayrefs and is
suitable for sending to JavaScript via JSON or sharing with other languages.
The parse_tree method is used for returning this AST.
Once at the AST stage, there are two modes of operation. Alloy can either
operate directly on the AST using the Play role, or it can compile the AST to
perl code via the Compile role, and then execute the code. To use the perl
code route, you must set the COMPILE_PERL flag to 1. If you are running in a
cached-in-memory environment such as mod_perl, this is the fastest option. If
you are running in a non-cached-in-memory environment, then using the Play
role to run the AST is generally faster. The AST method is also more secure as
cached AST won't ever eval any "perl" (assuming PERL blocks are
disabled - which is the default).
ROLES¶
Template::Alloy has split out its functionality into discrete roles. In
Template::Toolkit, this functionality is split into separate classes. The
roles in Template::Alloy simply add on more methods to the main class. When
Perl 6 arrives, these roles will be translated into true Roles.
The following is a list of roles used by Template::Alloy.
Template::Alloy::Compile - Compile-to-perl role
Template::Alloy::HTE - HTML::Template::Expr role
Template::Alloy::Operator - Operator role
Template::Alloy::Parse - Parse-to-AST role
Template::Alloy::Play - Play-AST role
Template::Alloy::Stream - Stream output role
Template::Alloy::Tmpl - Text::Tmpl role
Template::Alloy::TT - Template::Toolkit role
Template::Alloy::Velocity - Velocity role
Template::Alloy::VMethod - Virtual methods role
Template::Alloy automatically loads the roles when they are needed or requested
- but not sooner (with the exception of the Operator role and the VMethod role
which are always needed and always loaded). This is good for a CGI
environment. In mod_perl you may want to preload a role to make the most of
shared memory. You may do this by passing either the role name or a method
supplied by that role.
# import roles necessary for running TT
use Template::Alloy qw(Parse Play Compile TT);
# import roles based on methods
use Template::Alloy qw(parse_tree play_tree compile_tree process);
Note: importing roles by method names does not import them into that namespace -
it is autoloading the role and methods into the Template::Alloy namespace. To
help make this more clear you may use the following syntax as well.
# import roles necessary for running TT
use Template::Alloy load => qw(Parse Play Compile TT);
# import roles based on methods
use Template::Alloy load => qw(process parse_tree play_tree compile_tree);
# import roles based on methods
use Template::Alloy
Parse => 1,
Play => 1,
Compile => 1,
TT => 1;
Even with all roles loaded Template::Alloy is still relatively small. You can
load all of the roles by pass "all" to the use statement.
use Template::Alloy 'all';
# or
use Template::Alloy load => 'all';
# or
use Template::Alloy all => 1;
As a final option, Template::Alloy also includes the ability to stand-in for
other template modules. It is able to do this because it supports the majority
of the interface of the other template systems. You can do this in the
following way:
use Template::Alloy qw(Text::Tmpl HTML::Template);
# or
use Template::Alloy load => qw(Text::Tmpl HTML::Template);
# or
use Template::Alloy
'Text::Tmpl' => 1,
'HTML::Template' => 1;
Note that the use statement will die if any of the passed module names are
already loaded and not subclasses of Template::Alloy. This will avoid thinking
that you are using Template::Alloy when you really aren't. Using the 'all'
option won't automatically do this - you must mention the "stood-in"
modules by name.
The following modules may be "stood-in" for:
Template
Text::Tmpl
HTML::Template
HTML::Template::Expr
This feature is intended to make using Template::Alloy with existing code
easier. Most cases should work just fine. Almost all syntax will just work
(except Alloy may make some things work that were previously broken). However
Template::Alloy doesn't support 100% of the interface of any of the template
systems. If you are using "features-on-the-edge" then you may need
to re-write portions of your code that interact with the template system.
PUBLIC METHODS¶
The following section lists most of the publicly available methods. Some less
commonly used public methods are listed later in this document.
- "new"
-
my $obj = Template::Alloy->new({
INCLUDE_PATH => ['/my/path/to/content', '/my/path/to/content2'],
});
Arguments may be passed as a hash or as a hashref. Returns a Template::Alloy
object.
There are currently no errors during Template::Alloy object creation. If you
are using the HTML::Template interface, this is different behavior. The
document is not parsed until the output or process methods are
called.
- "process"
- This is the TT interface for starting processing. Any
errors that result in the template processing being stopped will be stored
and available via the ->error method.
my $t = Template::Alloy->new;
$t->process($in, $swap, $out)
|| die $t->error;
Process takes three arguments.
The $in argument can be any one of:
String containing the filename of the template to be processed. The filename should
be relative to INCLUDE_PATH. (See INCLUDE_PATH, ABSOLUTE, and RELATIVE configuration items).
In memory caching and file side caching are available for this type.
A reference to a scalar containing the contents of the template to be processed.
A coderef that will be called to return the contents of the template.
An open filehandle that will return the contents of the template when read.
The $swap argument should be hashref containing key value pairs that will be
available to variables swapped into the template. Values can be hashrefs,
hashrefs of hashrefs and so on, arrayrefs, arrayrefs of arrayrefs and so
on, coderefs, objects, and simple scalar values such as numbers and
strings. See the section on variables.
The $out argument can be any one of:
undef - meaning to print the completed template to STDOUT.
String containing a filename. The completed template will be placed in the file.
A reference to a string. The contents will be appended to the scalar reference.
A coderef. The coderef will be called with the contents as a single argument.
An object that can run the method "print". The contents will be passed as
a single argument to print.
An arrayref. The contents will be pushed onto the array.
An open filehandle. The contents will be printed to the open handle.
Additionally - the $out argument can be configured using the OUTPUT
configuration item.
The process method defaults to using the "cet" syntax which will
parse TT3 and most TT2 documents. To parse HT or HTE documents, you must
pass the SYNTAX configuration item to the "new" method. All
calls to process would then default to HTE syntax.
my $obj = Template::Alloy->new(SYNTAX => 'hte');
- "process_simple"
- Similar to the process method but with the following
restrictions:
The $in parameter is limited to a filename or a reference a string
containing the contents.
The $out parameter may only be a reference to a scalar string that output
will be appended to.
Additionally, the following configuration variables will be ignored:
VARIABLES, PRE_DEFINE, BLOCKS, PRE_PROCESS, PROCESS, POST_PROCESS,
AUTO_RESET, OUTPUT.
- "error"
- Should something go wrong during a "process"
command, the error that occurred can be retrieved via the error method.
$obj->process('somefile.html', {a => 'b'}, \$string_ref)
|| die $obj->error;
- "output"
- HTML::Template way to process a template. The output method
requires that a filename, filehandle, scalarref, or arrayref argument was
passed to the new method. All of the HT calling conventions for new are
supported. The key difference is that Alloy will not actually process the
template until the output method is called.
my $obj = Template::Alloy->new(filename => 'myfile.html');
$obj->param(\%swap);
print $obj->output;
See the HTML::Template documentation for more information.
The output method defaults to using the "hte" syntax which will
parse HTE and HT documents. To parse TT3 or TT2 documents, you must pass
the SYNTAX configuration item to the "new" method. All calls to
process would then default to TT3 syntax.
my $obj = Template::Alloy->new(SYNTAX => 'tt3');
Any errors that occur during the output method will die with the error as
the die value.
- "param"
- HTML::Template way to get or set variable values that will
be used by the output method.
my $val = $obj->param('key'); # get one value
$obj->param(key => $val); # set one value
$obj->param(key => $val, key2 => $val2); # set multiple
$obj->param({key => $val, key2 => $val2}); # set multiple
See the HTML::Template documentation for more information.
Note: Alloy does not support the die_on_bad_params configuration. This is
because Alloy does not resolve variable names until the output method is
called.
- "define_vmethod"
- This method is available for defining extra Virtual methods
or filters. This method is similar to Template::Stash::define_vmethod.
Template::Alloy->define_vmethod(
'text',
reverse => sub { my $item = shift; return scalar reverse $item },
);
- "register_function"
- This is the HTML::Template way of defining text vmethods.
It is the same as calling define_vmethod with "text" as the
first argument.
Template::Alloy->register_function(
reverse => sub { my $item = shift; return scalar reverse $item },
);
- "define_directive"
- This method can be used for adding new directives or
overridding existing ones.
Template::Alloy->define_directive(
MYDIR => {
parse_sub => sub {}, # parse additional items in the tag
play_sub => sub {
my ($self, $ref, $node, $out_ref) = @_;
$$out_ref .= "I always say the same thing!";
return;
},
is_block => 1, # is this block like
is_postop => 0, # not a post operative directive
no_interp => 1, # no interpolation in this block
continues => undef, # it doesn't "continue" any other directives
},
);
Now with a template like:
my $str = "([% MYDIR %]This is something[% END %])";
Template::Alloy->new->process(\$str);
You will get:
(I always say the same thing!)
We'll add more details in later revisions of this document.
- "define_syntax"
- This method can be used for adding other syntaxes to or
overridding existing ones in the list of choices available in Alloy. The
syntax can be chosen by the SYNTAX configuration item.
Template::Alloy->define_syntax(
my_uber_syntax => sub {
my $self = shift;
local $self->{'V2PIPE'} = 0;
local $self->{'V2EQUALS'} = 0;
local $self->{'PRE_CHOMP'} = 0;
local $self->{'POST_CHOMP'} = 0;
local $self->{'NO_INCLUDES'} = 0;
return $self->parse_tree_tt3(@_);
},
);
The subroutine that is used must return an opcode tree (AST) that can be
played by the execute_tree method.
- "define_operator"
- This method allows for adding new operators or overriding
existing ones.
Template::Alloy->define_operator({
type => 'right', # can be one of prefix, postfix, right, left, none, ternary, assign
precedence => 84, # relative precedence for resolving multiple operators without parens
symbols => ['foo', 'FOO'], # any mix of chars can be used for the operators
play_sub => sub {
my ($one, $two) = @_;
return "You've been foo'ed ($one, $two)";
},
});
You can then use it in a template as in the following:
my $str = "[% 'ralph' foo 1 + 2 * 3 %]";
Template::Alloy->new->process(\$str);
You will get:
You've been foo'ed (ralph, 7)
Future revisions of this document will include more samples. This is an
experimental feature and the api will probably change.
- "dump_parse_tree"
- This method allows for returning a Data::Dumper dump of a
parsed template. It is mainly used for testing.
- "dump_parse_expr"
- This method allows for returning a Data::Dumper dump of a
parsed variable. It is mainly used for testing.
- "import"
- All of the arguments that can be passed to "use"
that are listed above in the section dealing with ROLES, can be used with
the import method.
# import by role
Template::Alloy->import(qw(Compile Play Parse TT));
# import by method
Template::Alloy->import(qw(compile_tree play_tree parse_tree process));
# import by "stand-in" class
Template::Alloy->import('Text::Tmpl', 'HTML::Template::Expr');
As mentioned in the ROLE section - arguments passed to import are not
imported into current namespace. Roles and methods are only imported into
the Template::Alloy namespace.
VARIABLES¶
This section discusses how to use variables and expressions in the TT
mini-language.
A variable is the most simple construct to insert into the TT mini language. A
variable name will look for the matching value inside Template::Alloys
internal stash of variables which is essentially a hash reference. This stash
is initially populated by either passing a hashref as the second argument to
the process method, or by setting the "VARIABLES" or
"PRE_DEFINE" configuration variables.
If you are using the HT and HTE syntaxes, the VAR, IF, UNLESS, LOOP, and INCLUDE
directives will accept a NAME attribute which may only be a single level
(non-chained) HTML::Template variable name, or they may accept an EXPR
attribute which may be any valid TT3 variable or expression.
The following are some sample ways to access variables.
### some sample variables
my %vars = (
one => '1.0',
foo => 'bar',
vname => 'one',
some_code => sub { "You passed me (".join(', ', @_).")" },
some_data => {
a => 'A',
bar => 3234,
c => [3, 1, 4, 1, 5, 9],
vname => 'one',
},
my_list => [20 .. 50],
cet => Template::Alloy->new,
);
### pass the variables into the Alloy process
$cet->process($template_name, \%vars)
|| die $cet->error;
### pass the variables during object creation (will be available to every process call)
my $cet = Template::Alloy->new(VARIABLES => \%vars);
GETTING VARIABLES¶
Once you have variables defined, they can be used directly in the template by
using their name in the stash. Or by using the GET directive.
[% foo %]
[% one %]
[% GET foo %]
Would print when processed:
bar
1.0
bar
To access members of a hashref or an arrayref, you can chain together the names
using a ".".
[% some_data.a %]
[% my_list.0] [% my_list.1 %] [% my_list.-1 %]
[% some_data.c.2 %]
Would print:
A
20 21 50
4
If the value of a variable is a code reference, it will be called. You can add a
set of parenthesis and arguments to pass arguments. Arguments are variables
and can be as complex as necessary.
[% some_code %]
[% some_code() %]
[% some_code(foo) %]
[% some_code(one, 2, 3) %]
Would print:
You passed me ().
You passed me ().
You passed me (bar).
You passed me (1.0, 2, 3).
If the value of a variable is an object, methods can be called using the
"." operator.
[% cet %]
[% cet.dump_parse_expr('1 + 2').replace('\s+', ' ') %]
Would print something like:
Template::Alloy=HASH(0x814dc28)
$VAR1 = [ [ undef, '+', '1', '2' ], 0 ];
Each type of data (string, array and hash) have virtual methods associated with
them. Virtual methods allow for access to functions that are commonly used on
those types of data. For the full list of built in virtual methods, please see
the section titled VIRTUAL METHODS
[% foo.length %]
[% my_list.size %]
[% some_data.c.join(" | ") %]
Would print:
3
31
3 | 1 | 4 | 5 | 9
It is also possible to "interpolate" variable names using a
"$". This allows for storing the name of a variable inside another
variable. If a variable name is a little more complex it can be embedded
inside of "${" and "}".
[% $vname %]
[% ${vname} %]
[% ${some_data.vname} %]
[% some_data.$foo %]
[% some_data.${foo} %]
Would print:
1.0
1.0
1.0
3234
3234
In Alloy it is also possible to embed any expression (non-directive) in
"${" and "}" and it is possible to use non-integers for
array access. (This is not available in TT2)
[% ['a'..'z'].${ 2.3 } %]
[% {ab => 'AB'}.${ 'a' ~ 'b' } %]
[% color = qw/Red Blue/; FOR [1..4] ; color.${ loop.index % color.size } ; END %]
Would print:
c
AB
RedBlueRedBlue
SETTING VARIABLES.¶
To define variables during processing, you can use the = operator. In most cases
this is the same as using the SET directive.
[% a = 234 %][% a %]
[% SET b = "Hello" %][% b %]
Would print:
234
Hello
It is also possible to create arrayrefs and hashrefs.
[% a = [1, 2, 3] %]
[% b = {key1 => 'val1', 'key2' => 'val2'} %]
[% a.1 %]
[% b.key1 %] [% b.key2 %]
Would print:
2
val1 val2
It is possible to set multiple values in the same SET directive.
[% SET a = 'A'
b = 'B'
c = 'C' %]
[% a %] [% b %] [% c %]
Would print:
A B C
It is also possible to unset variables, or to set members of nested data
structures.
[% a = 1 %]
[% SET a %]
[% b.0.c = 37 %]
([% a %])
[% b.0.c %]
Would print
()
37
LITERALS AND CONSTRUCTORS¶
The following are the types of literals (numbers and strings) and constructors
(hash and array constructs) allowed in Alloy. They can be used as arguments to
functions, in place of variables in directives, and in place of variables in
expressions. In Alloy it is also possible to call virtual methods on literal
values.
- Integers and Numbers.
-
[% 23423 %] Prints an integer.
[% 3.14159 %] Prints a number.
[% pi = 3.14159 %] Sets the value of the variable.
[% 3.13159.length %] Prints 7 (the string length of the number)
Scientific notation is supported.
[% 314159e-5 + 0 %] Prints 3.14159.
[% .0000001.fmt('%.1e') %] Prints 1.0e-07
Hexidecimal input is also supported.
[% 0xff + 0 %] Prints 255
[% 48875.fmt('%x') %] Prints beeb
- Single quoted strings.
- Returns the string. No variable interpolation happens.
[% 'foobar' %] Prints "foobar".
[% '$foo\n' %] Prints "$foo\\n". # the \\n is a literal "\" and an "n"
[% 'That\'s nice' %] Prints "That's nice".
[% str = 'A string' %] Sets the value of str.
[% 'A string'.split %] Splits the string on ' ' and returns the list.
Note: virtual methods can only be used on literal strings in Alloy, not in
TT.
You may also embed the current tags in strings (Alloy only).
[% '[% 1 + 2 %]' | eval %] Prints "3"
- Double quoted strings.
- Returns the string. Variable interpolation happens.
[% "foobar" %] Prints "foobar".
[% "$foo" %] Prints "bar" (assuming the value of foo is bar).
[% "${foo}" %] Prints "bar" (assuming the value of foo is bar).
[% "foobar\n" %] Prints "foobar\n". # the \n is a newline.
[% str = "Hello" %] Sets the value of str.
[% "foo".replace('foo','bar') %] Prints "bar".
Note: virtual methods can only be used on literal strings in Alloy, not in
TT.
You may also embed the current tags in strings (Alloy only).
[% "[% 1 + 2 %]" | eval %] Prints "3"
- Array Constructs.
-
[% [1, 2, 3] %] Prints something like ARRAY(0x8309e90).
[% array1 = [1 .. 3] %] Sets the value of array1.
[% array2 = [foo, 'a', []] %] Sets the value of array2.
[% [4, 5, 6].size %] Prints 3.
[% [7, 8, 9].reverse.0 %] Prints 9.
Note: virtual methods can only be used on array contructs in Alloy, not in
TT.
- Quoted Array Constructs.
-
[% qw/1 2 3/ %] Prints something like ARRAY(0x8309e90).
[% array1 = qw{Foo Bar Baz} %] Sets the value of array1.
[% qw[4 5 6].size %] Prints 3.
[% qw(Red Blue).reverse.0 %] Prints Blue.
Note: this works in Alloy and is planned for TT3.
- Hash Constructs.
-
[% {foo => 'bar'} %] Prints something like HASH(0x8305880)
[% hash = {foo => 'bar', c => {}} %] Sets the value of hash.
[% {a => 'A', b => 'B'}.size %] Prints 2.
[% {'a' => 'A', 'b' => 'B'}.size %] Prints 2.
[% name = "Tom" %]
[% {Tom => 'You are Tom',
Kay => 'You are Kay'}.$name %] Prints You are Tom
Note: virtual methods can only be used on hash contructs in Alloy, not in
TT.
- Regex Constructs.
-
[% /foo/ %] Prints (?-xism:foo)
[% a = /(foo)/i %][% "FOO".match(a).0 %] Prints FOO
Note: this works in Alloy and is planned for TT3.
VIRTUAL METHODS¶
Virtual methods (vmethods) are a TT feature that allow for operating on the
swapped template variables.
This document shows some samples of using vmethods. For a full listing of
available virtual methods, see Template::Alloy::VMethod.
EXPRESSIONS¶
Expressions are one or more variables or literals joined together with
operators. An expression can be used anywhere a variable can be used with the
exception of the variable name in the SET directive, and the filename of
PROCESS, INCLUDE, WRAPPER, and INSERT.
For a full listing of operators, see Template::Alloy::Operator.
The following section shows some samples of expressions. For a full list of
available operators, please see the section titled OPERATORS.
[% 1 + 2 %] Prints 3
[% 1 + 2 * 3 %] Prints 7
[% (1 + 2) * 3 %] Prints 9
[% x = 2 %] # assignments don't return anything
[% (x = 2) %] Prints 2 # unless they are in parens
[% y = 3 %]
[% x * (y - 1) %] Prints 4
DIRECTIVES¶
This section contains the alphabetical list of DIRECTIVES available in Alloy.
DIRECTIVES are the "functions" and control structures that work in
the various mini-languages. For further discussion and examples beyond what is
listed below, please refer to the TT directives documentation or to the
appropriate documentation for the particular directive.
The examples given in this section are done using the Template::Toolkit syntax,
but can be done in any of the various syntaxes. See Template::Alloy::TT,
Template::Alloy::HTE, Template::Alloy::Tmpl, and Template::Alloy::Velocity.
[% IF 1 %]One[% END %]
[% FOREACH a = [1 .. 3] %]
a = [% a %]
[% END %]
[% SET a = 1 %][% SET a = 2 %][% GET a %]
In TT multiple directives can be inside the same set of '[%' and '%]' tags as
long as they are separated by space or semi-colons (;) (The Alloy version of
Tmpl allows multiple also - but none of the other syntaxes do). Any block
directive that can also be used as a post-operative directive (such as IF,
WHILE, FOREACH, UNLESS, FILTER, and WRAPPER) must be separated from preceding
directives with a semi-colon if it is being used as a block directive. It is
more safe to always use a semi-colon. Note: separating by space is only
available in Alloy but is a planned TT3 feature.
[% SET a = 1 ; SET a = 2 ; GET a %]
[% SET a = 1
SET a = 2
GET a
%]
[% GET 1
IF 0 # is a post-operative
GET 2 %] # prints 2
[% GET 1;
IF 0 # it is block based
GET 2
END
%] # prints 1
The following is the list of directives.
- "BLOCK"
- Saves a block of text under a name for later use in
PROCESS, INCLUDE, and WRAPPER directives. Blocks may be placed anywhere
within the template being processed including after where they are used.
[% BLOCK foo %]Some text[% END %]
[% PROCESS foo %]
Would print
Some text
[% INCLUDE foo %]
[% BLOCK foo %]Some text[% END %]
Would print
Some text
Anonymous BLOCKS can be used for capturing.
[% a = BLOCK %]Some text[% END %][% a %]
Would print
Some text
Anonymous BLOCKS can be used with macros.
- "BREAK"
- Alias for LAST. Used for exiting FOREACH and WHILE
loops.
- "CALL"
- Calls the variable (and any underlying coderefs) as in the
GET method, but always returns an empty string.
- "CASE"
- Used with the SWITCH directive. See the "SWITCH"
directive.
- "CATCH"
- Used with the TRY directive. See the "TRY"
directive.
- "CLEAR"
- Clears any of the content currently generated in the
innermost block or template. This can be useful when used in conjunction
with the TRY statement to clear generated content if an error occurs
later.
- "COMMENT"
- Will comment out any text found between open and close
tags. Note, that the intermediate items are still parsed and END tags must
align - but the parsed content will be discarded.
[% COMMENT %]
This text won't be shown.
[% IF 1 %]And this won't either.[% END %]
[% END %]
- "CONFIG"
- Allow for changing the value of some compile time and
runtime configuration options.
[% CONFIG
ANYCASE => 1
PRE_CHOMP => '-'
%]
The following compile time configuration options may be set:
ANYCASE
AUTO_EVAL
AUTO_FILTER
CACHE_STR_REFS
ENCODING
INTERPOLATE
POST_CHOMP
PRE_CHOMP
SEMICOLONS
SHOW_UNDEFINED_INTERP
SYNTAX
V1DOLLAR
V2EQUALS
V2PIPE
The following runtime configuration options may be set:
ADD_LOCAL_PATH
CALL_CONTEXT
DUMP
VMETHOD_FUNCTIONS
STRICT (can only be enabled, cannot be disabled)
If non-named parameters as passed, they will show the current configuration:
[% CONFIG ANYCASE, PRE_CHOMP %]
CONFIG ANYCASE = undef
CONFIG PRE_CHOMP = undef
- "DEBUG"
- Used to reset the DEBUG_FORMAT configuration variable, or
to turn DEBUG statements on or off. This only has effect if the DEBUG_DIRS
or DEBUG_ALL flags were passed to the DEBUG configuration variable.
[% DEBUG format '($file) (line $line) ($text)' %]
[% DEBUG on %]
[% DEBUG off %]
- "DEFAULT"
- Similar to SET, but only sets the value if a previous value
was not defined or was zero length.
[% DEFAULT foo = 'bar' %][% foo %] => 'bar'
[% foo = 'baz' %][% DEFAULT foo = 'bar' %][% foo %] => 'baz'
- "DUMP"
- DUMP inserts a Data::Dumper printout of the variable or
expression. If no argument is passed it will dump the entire contents of
the current variable stash (with private keys removed).
The output also includes the current file and line number that the DUMP
directive was called from.
See the DUMP configuration item for ways to customize and control the output
available to the DUMP directive.
[% DUMP %] # dumps everything
[% DUMP 1 + 2 %]
- "ELSE"
- Used with the IF directive. See the "IF"
directive.
- "ELSIF"
- Used with the IF directive. See the "IF"
directive.
- "END"
- Used to end a block directive.
- "EVAL"
- Same as the EVALUATE directive.
- "EVALUATE"
- Introduced by the Velocity templating language. Parses and
processes the contents of the passed item. This is similar to the eval
filter, but Velocity needs a directive. Named arguments may be used for
reconfiguring the parser. Any of the items that can be passed to the
CONFIG directive may be passed here.
[% EVALUATE "[% 1 + 3 %]" %]
[% foo = "bar" %]
[% EVALUATE "<TMPL_VAR foo>" SYNTAX => 'ht' %]
- "FILTER"
- Used to apply different treatments to blocks of text. It
may operate as a BLOCK directive or as a post operative directive. Alloy
supports all of the filters in Template::Filters. The lines between scalar
virtual methods and filters is blurred (or non-existent) in Alloy.
Anything that is a scalar virtual method may be used as a FILTER.
TODO - enumerate the at least 7 ways to pass and use filters.
- '|'
- Alias for the FILTER directive. Note that | is similar to
the '.' in Template::Alloy. Therefore a pipe cannot be used directly after
a variable name in some situations (the pipe will act only on that
variable). This is the behavior employed by TT3. To get the TT2 behavior
for a PIPE, use the V2PIPE configuration item.
- "FINAL"
- Used with the TRY directive. See the "TRY"
directive.
- "FOR"
- Alias for FOREACH
- "FOREACH"
- Allows for iterating over the contents of any arrayref. If
the variable is not an arrayref, it is automatically promoted to one.
[% FOREACH i IN [1 .. 3] %]
The variable i = [% i %]
[%~ END %]
[% a = [1 .. 3] %]
[% FOREACH j IN a %]
The variable j = [% j %]
[%~ END %]
Would print:
The variable i = 1
The variable i = 2
The variable i = 3
The variable j = 1
The variable j = 2
The variable j = 3
You can also use the "=" instead of "IN" or
"in".
[% FOREACH i = [1 .. 3] %]
The variable i = [% i %]
[%~ END %]
Same as before.
Setting into a variable is optional.
[% a = [1 .. 3] %]
[% FOREACH a %] Hi [% END %]
Would print:
hi hi hi
If the item being iterated is a hashref and the FOREACH does not set into a
variable, then values of the hashref are copied into the variable stash.
[% FOREACH [{a => 1}, {a => 2}] %]
Key a = [% a %]
[%~ END %]
Would print:
Key a = 1
Key a = 2
The FOREACH process uses the Template::Alloy::Iterator class to handle
iterations (It is compatible with Template::Iterator). During the FOREACH
loop an object blessed into the iterator class is stored in the variable
"loop".
The loop variable provides the following information during a FOREACH:
index - the current index
max - the max index of the list
size - the number of items in the list
count - index + 1
number - index + 1
first - true if on the first item
last - true if on the last item
next - return the next item in the list
prev - return the previous item in the list
odd - return 1 if the current count is odd, 0 otherwise
even - return 1 if the current count is even, 0 otherwise
parity - return "odd" if the current count is odd, "even" otherwise
The following:
[% FOREACH [1 .. 3] %] [% loop.count %]/[% loop.size %] [% END %]
Would print:
1/3 2/3 3/3
The iterator is also available using a plugin. This allows for access to
multiple "loop" variables in a nested FOREACH directive.
[%~ USE outer_loop = Iterator(["a", "b"]) %]
[%~ FOREACH i = outer_loop %]
[%~ FOREACH j = ["X", "Y"] %]
[% outer_loop.count %]-[% loop.count %] = ([% i %] and [% j %])
[%~ END %]
[%~ END %]
Would print:
1-1 = (a and X)
1-2 = (a and Y)
2-1 = (b and X)
2-2 = (b and Y)
FOREACH may also be used as a post operative directive.
[% "$i" FOREACH i = [1 .. 5] %] => 12345
- "GET"
- Return the value of a variable or expression.
[% GET a %]
The GET keyword may be omitted.
[% a %]
[% 7 + 2 - 3 %] => 6
See the section on VARIABLES.
- "IF (IF / ELSIF / ELSE)"
- Allows for conditional testing. Expects an expression as
its only argument. If the expression is true, the contents of its block
are processed. If false, the processor looks for an ELSIF block. If an
ELSIF's expression is true then it is processed. Finally it looks for an
ELSE block which is processed if none of the IF or ELSIF's expressions
were true.
[% IF a == b %]A equaled B[% END %]
[% IF a == b -%]
A equaled B
[%- ELSIF a == c -%]
A equaled C
[%- ELSE -%]
Couldn't determine that A equaled anything.
[%- END %]
IF may also be used as a post operative directive.
[% 'A equaled B' IF a == b %]
Note: If you are using HTML::Template style documents, the TMPL_IF tag
parses using the limited HTML::Template parsing rules. However, you may
use EXPR="" to embed a TT3 style expression.
- "INCLUDE"
- Parse the contents of a file or block and insert them.
Variables defined or modifications made to existing variables are
discarded after a template is included.
[% INCLUDE path/to/template.html %]
[% INCLUDE "path/to/template.html" %]
[% file = "path/to/template.html" %]
[% INCLUDE $file %]
[% BLOCK foo %]This is foo[% END %]
[% INCLUDE foo %]
Arguments may also be passed to the template:
[% INCLUDE "path/to/template.html" a = "An arg" b = "Another arg" %]
Filenames must be relative to INCLUDE_PATH unless the ABSOLUTE or RELATIVE
configuration items are set.
Multiple filenames can be passed by separating them with a plus, a space, or
commas (TT2 doesn't support the comma). Any supplied arguments will be
used on all templates.
[% INCLUDE "path/to/template.html",
"path/to/template2.html" a = "An arg" b = "Another arg" %]
On Perl 5.6 on some platforms there may be some issues with the variable
localization. There is no problem on 5.8 and greater.
- "INSERT"
- Insert the contents of a file without template parsing.
Filenames must be relative to INCLUDE_PATH unless the ABSOLUTE or RELATIVE
configuration items are set.
Multiple filenames can be passed by separating them with a plus, a space, or
commas (TT2 doesn't support the comma).
[% INSERT "path/to/template.html",
"path/to/template2.html" %]
- "LAST"
- Used to exit out of a WHILE or FOREACH loop.
- "LOOP"
- This directive operates similar to the HTML::Template loop
directive. The LOOP directive expects a single variable name. This
variable name should point to an arrayref of hashrefs. The keys of each
hashref will be added to the variable stash when it is iterated.
[% var a = [{b => 1}, {b => 2}, {b => 3}] %]
[% LOOP a %] ([% b %]) [% END %]
Would print:
(1) (2) (3)
If Alloy is in HT mode and GLOBAL_VARS is false, the contents of the hashref
will be the only items available during the loop iteration.
If LOOP_CONTEXT_VARS is true, and $QR_PRIVATE is false (default when called
through the output method), then the variables __first__, __last__,
__inner__, __odd__, and __counter__ will be set. See the HTML::Template
loop_context_vars configuration item for more information.
- "MACRO"
- Takes a directive and turns it into a variable that can
take arguments.
[% MACRO foo(i, j) BLOCK %]You passed me [% i %] and [% j %].[% END %]
[%~ foo("a", "b") %]
[% foo(1, 2) %]
Would print:
You passed me a and b.
You passed me 1 and 2.
Another example:
[% MACRO bar(max) FOREACH i = [1 .. max] %]([% i %])[% END %]
[%~ bar(4) %]
Would print:
(1)(2)(3)(4)
Starting with version 1.012 of Template::Alloy there is also a macro
operator.
[% foo = ->(i,j){ "You passed me $i and $j" } %]
[% bar = ->(max){ FOREACH i = [1 .. max]; i ; END } %]
See the Template::Alloy::Operator documentation for more examples.
- "META"
- Used to define variables that will be available via either
the template or component namespace.
Once defined, they cannot be overwritten.
[% template.foobar %]
[%~ META foobar = 'baz' %]
[%~ META foobar = 'bing' %]
Would print:
baz
- "NEXT"
- Used to go to the next iteration of a WHILE or FOREACH
loop.
- "PERL"
- Only available if the EVAL_PERL configuration item is true
(default is false).
Allow eval'ing the block of text as perl. The block will be parsed and then
eval'ed.
[% a = "BimBam" %]
[%~ PERL %]
my $a = "[% a %]";
print "The variable \$a was \"$a\"";
$stash->set('b', "FooBar");
[% END %]
[% b %]
Would print:
The variable $a was "BimBam"
FooBar
During execution, anything printed to STDOUT will be inserted into the
template. Also, the $stash and $context variables are set and are
references to objects that mimic the interface provided by
Template::Context and Template::Stash. These are provided for
compatibility only. $self contains the current Template::Alloy
object.
- "PROCESS"
- Parse the contents of a file or block and insert them.
Unlike INCLUDE, no variable localization happens so variables defined or
modifications made to existing variables remain after the template is
processed.
[% PROCESS path/to/template.html %]
[% PROCESS "path/to/template.html" %]
[% file = "path/to/template.html" %]
[% PROCESS $file %]
[% BLOCK foo %]This is foo[% END %]
[% PROCESS foo %]
Arguments may also be passed to the template:
[% PROCESS "path/to/template.html" a = "An arg" b = "Another arg" %]
Filenames must be relative to INCLUDE_PATH unless the ABSOLUTE or RELATIVE
configuration items are set.
Multiple filenames can be passed by separating them with a plus, a space, or
commas (TT2 doesn't support the comma). Any supplied arguments will be
used on all templates.
[% PROCESS "path/to/template.html",
"path/to/template2.html" a = "An arg" b = "Another arg" %]
- "RAWPERL"
- Only available if the EVAL_PERL configuration item is true
(default is false). Similar to the PERL directive, but you will need to
append to the $output variable rather than just calling PRINT.
- "RETURN"
- Used to exit the innermost block or template and continue
processing in the surrounding block or template.
There are two changes from TT2 behavior. First, In Alloy, a RETURN during a
MACRO call will only exit the MACRO. Second, the RETURN directive takes an
optional variable name or expression, if passed, the MACRO will return
this value instead of the normal text from the MACRO. The process_simple
method will also return this value.
You can also use the item, list, and hash return vmethods.
[% RETURN %] # just exits
[% RETURN "foo" %] # return value is foo
[% "foo".return %] # same thing
- "SET"
- Used to set variables.
[% SET a = 1 %][% a %] => "1"
[% a = 1 %][% a %] => "1"
[% b = 1 %][% SET a = b %][% a %] => "1"
[% a = 1 %][% SET a %][% a %] => ""
[% SET a = [1, 2, 3] %][% a.1 %] => "2"
[% SET a = {b => 'c'} %][% a.b %] => "c"
- "STOP"
- Used to exit the entire process method (out of all blocks
and templates). No content will be processed beyond this point.
- "SWITCH"
- Allow for SWITCH and CASE functionality.
[% a = "hi" %]
[% b = "bar" %]
[% SWITCH a %]
[% CASE "foo" %]a was foo
[% CASE b %]a was bar
[% CASE ["hi", "hello"] %]You said hi or hello
[% CASE DEFAULT %]I don't know what you said
[% END %]
Would print:
You said hi or hello
- "TAGS"
- Change the type of enclosing braces used to delineate
template tags. This remains in effect until the end of the enclosing block
or template or until the next TAGS directive. Either a named set of tags
must be supplied, or two tags themselves must be supplied.
[% TAGS html %]
[% TAGS <!-- --> %]
The named tags are (duplicated from TT):
asp => ['<%', '%>' ], # ASP
default => ['\[%', '%\]' ], # default
html => ['<!--', '-->' ], # HTML comments
mason => ['<%', '>' ], # HTML::Mason
metatext => ['%%', '%%' ], # Text::MetaText
php => ['<\?', '\?>' ], # PHP
star => ['\[\*', '\*\]' ], # TT alternate
template => ['\[%', '%\]' ], # Normal Template Toolkit
template1 => ['[\[%]%', '%[%\]]'], # allow TT1 style
tt2 => ['\[%', '%\]' ], # TT2
If custom tags are supplied, by default they are escaped using quotemeta.
You may also pass explicitly quoted strings, or regular expressions as
arguments as well (if your regex begins with a ', ", or / you must
quote it.
[% TAGS [<] [>] %] matches "[<] tag [>]"
[% TAGS '[<]' '[>]' %] matches "[<] tag [>]"
[% TAGS "[<]" "[>]" %] matches "[<] tag [>]"
[% TAGS /[<]/ /[>]/ %] matches "< tag >"
[% TAGS ** ** %] matches "** tag **"
[% TAGS /**/ /**/ %] Throws an exception.
You should be sure that the start tag does not include grouping parens or
INTERPOLATE will not function properly.
- "THROW"
- Allows for throwing an exception. If the exception is not
caught via the TRY DIRECTIVE, the template will abort processing of the
directive.
[% THROW mytypes.sometime 'Something happened' arg1 => val1 %]
See the TRY directive for examples of usage.
- "TRY"
- The TRY block directive will catch exceptions that are
thrown while processing its block (It cannot catch parse errors unless
they are in included files or evaltt'ed strings. The TRY block will then
look for a CATCH block that will be processed. While it is being
processed, the "error" variable will be set with the thrown
exception as the value. After the TRY block - the FINAL block will be ran
whether or not an error was thrown (unless a CATCH block throws an error).
Note: Parse errors cannot be caught unless they are in an eval FILTER, or
are in a separate template being INCLUDEd or PROCESSed.
[% TRY %]
Nothing bad happened.
[% CATCH %]
Caught the error.
[% FINAL %]
This section runs no matter what happens.
[% END %]
Would print:
Nothing bad happened.
This section runs no matter what happens.
Another example:
[% TRY %]
[% THROW "Something happened" %]
[% CATCH %]
Error: [% error %]
Error.type: [% error.type %]
Error.info: [% error.info %]
[% FINAL %]
This section runs no matter what happens.
[% END %]
Would print:
Error: undef error - Something happened
Error.type: undef
Error.info: Something happened
This section runs no matter what happens.
You can give the error a type and more information including named
arguments. This information replaces the "info" property of the
exception.
[% TRY %]
[% THROW foo.bar "Something happened" "grrrr" foo => 'bar' %]
[% CATCH %]
Error: [% error %]
Error.type: [% error.type %]
Error.info: [% error.info %]
Error.info.0: [% error.info.0 %]
Error.info.1: [% error.info.1 %]
Error.info.args.0: [% error.info.args.0 %]
Error.info.foo: [% error.info.foo %]
[% END %]
Would print something like:
Error: foo.bar error - HASH(0x82a395c)
Error.type: foo.bar
Error.info: HASH(0x82a395c)
Error.info.0: Something happened
Error.info.1: grrrr
Error.info.args.0: Something happened
Error.info.foo: bar
You can also give the CATCH block a type to catch. And you can nest TRY
blocks. If types are specified, Alloy will try and find the closest
matching type. Also, an error object can be re-thrown using $error as the
argument to THROW.
[% TRY %]
[% TRY %]
[% THROW foo.bar "Something happened" %]
[% CATCH bar %]
Caught bar.
[% CATCH DEFAULT %]
Caught default - but rethrew.
[% THROW $error %]
[% END %]
[% CATCH foo %]
Caught foo.
[% CATCH foo.bar %]
Caught foo.bar.
[% CATCH %]
Caught anything else.
[% END %]
Would print:
Caught default - but rethrew.
Caught foo.bar.
- "UNLESS"
- Same as IF but condition is negated.
[% UNLESS 0 %]hi[% END %] => hi
Can also be a post operative directive.
- "USE"
- Allows for loading a Template::Toolkit style plugin.
[% USE iter = Iterator(['foo', 'bar']) %]
[%~ iter.get_first %]
[% iter.size %]
Would print:
foo
2
Note that it is possible to send arguments to the new object constructor. It
is also possible to omit the variable name being assigned. In that case
the name of the plugin becomes the variable.
[% USE Iterator(['foo', 'bar', 'baz']) %]
[%~ Iterator.get_first %]
[% Iterator.size %]
Would print:
foo
3
Plugins that are loaded are looked up for in the namespace listed in the
PLUGIN_BASE directive which defaults to Template::Plugin. So in the
previous example, if Template::Toolkit was installed, the iter object
would loaded by the class Template::Plugin::Iterator. In Alloy, an
effective way to disable plugins is to set the PLUGIN_BASE to a
non-existent base such as "_" (In TT it will still fall back to
look in Template::Plugin).
Note: The iterator plugin will fall back and use Template::Alloy::Iterator
if Template::Toolkit is not installed. No other plugins come installed
with Template::Alloy.
The names of the Plugin being loaded from PLUGIN_BASE are case insensitive.
However, using case insensitive names is bad as it requires scanning the
@INC directories for any module matching the PLUGIN_BASE and caching the
result (OK - not that bad).
If the plugin is not found and the LOAD_PERL directive is set, then Alloy
will try and load a module by that name (note: this type of lookup is case
sensitive and will not scan the @INC dirs for a matching file).
# The LOAD_PERL directive should be set to 1
[% USE ta = Template::Alloy %]
[%~ ta.dump_parse_expr('2 * 3') %]
Would print:
[[undef, '*', 2, 3], 0];
See the PLUGIN_BASE, and PLUGINS configuration items.
See the documentation for Template::Manual::Plugins.
- "VIEW"
- Implement a TT style view. For more information, please see
the Template::View documentation. This DIRECTIVE will correctly parse the
arguments and then pass them along to a newly created Template::View
object. It will fail if Template::View can not be found.
- "WHILE"
- Will process a block of code while a condition is true.
[% WHILE i < 3 %]
[%~ i = i + 1 %]
i = [% i %]
[%~ END %]
Would print:
i = 1
i = 2
i = 3
You could also do:
[% i = 4 %]
[% WHILE (i = i - 1) %]
i = [% i %]
[%~ END %]
Would print:
i = 3
i = 2
i = 1
Note that (f = f - 1) is a valid expression that returns the value of the
assignment. The parenthesis are not optional.
WHILE has a built in limit of 1000 iterations. This is controlled by the
global variable $WHILE_MAX in Template::Alloy.
WHILE may also be used as a post operative directive.
[% "$i" WHILE (i = i + 1) < 7 %] => 123456
- "WRAPPER"
- Block directive. Processes contents of its block and then
passes them in the [% content %] variable to the block or filename listed
in the WRAPPER tag.
[% WRAPPER foo b = 23 %]
My content to be processed ([% b %]).[% a = 2 %]
[% END %]
[% BLOCK foo %]
A header ([% a %]).
[% content %]
A footer ([% a %]).
[% END %]
This would print.
A header (2).
My content to be processed (23).
A footer (2).
The WRAPPER directive may also be used as a post operative directive.
[% BLOCK baz %]([% content %])[% END -%]
[% "foobar" WRAPPER baz %]
Would print
(foobar)');
Multiple filenames can be passed by separating them with a plus, a space, or
commas (TT2 doesn't support the comma). Any supplied arguments will be
used on all templates. Wrappers are processed in reverse order, so that
the first wrapper listed will surround each subsequent wrapper listed.
Variables from inner wrappers are available to the next wrapper that
surrounds it.
[% WRAPPER "path/to/outer.html",
"path/to/inner.html" a = "An arg" b = "Another arg" %]
DIRECTIVES (HTML::Template Style)¶
HTML::Template templates use directives that look similar to the following:
<TMPL_VAR NAME="foo">
<TMPL_IF NAME="bar">
BAR
</TMPL_IF>
The normal set of HTML::Template directives are TMPL_VAR, TMPL_IF, TMPL_ELSE,
TMPL_UNLESS, TMPL_INCLUDE, and TMPL_LOOP. These tags should have either a NAME
attribute, an EXPR attribute, or a bare variable name that is used to specify
the value to be operated. If a NAME is specified, it may only be a single
level value (as opposed to a TT chained variable). In the case of the
TMPL_INCLUDE directive, the NAME is the file to be included.
In Alloy, the EXPR attribute can be used with any of these types to specify TT
compatible variable or expression that will be used for the value.
<TMPL_VAR NAME="foo"> Prints the value contained in foo
<TMPL_VAR foo> Prints the value contained in foo
<TMPL_VAR EXPR="foo"> Prints the value contained in foo
<TMPL_VAR NAME="foo.bar.baz"> Prints the value contained in {'foo.bar.baz'}
<TMPL_VAR EXPR="foo.bar.baz"> Prints the value contained in {foo}->{bar}->{baz}
<TMPL_IF foo> Prints FOO if foo is true
FOO
</TMPL_IF
<TMPL_UNLESS foo> Prints FOO unless foo is true
FOO
</TMPL_UNLESS
<TMPL_INCLUDE NAME="foo.ht"> Includes the template in "foo.ht"
<TMPL_LOOP foo> Iterates on the arrayref foo
<TMPL_VAR name>
</TMPL_LOOP>
Template::Alloy makes all of the other TT3 directives available in addition to
the normal set of HTML::Template directives. For example, the following is
valid in Alloy.
<TMPL_MACRO bar(n) BLOCK>You said <TMPL_VAR n></TMPL_MACRO>
<TMPL_GET bar("hello")>
The TMPL_VAR tag may also include an optional ESCAPE attribute. This specifies
how the value of the tag should be escaped prior to substituting into the
template.
Escape value | Type of escape
---------------------------------
HTML, 1 | HTML encoding
URL | URL encoding
JS | basic javascript encoding (\n, \r, and \")
NONE, 0 | No encoding (default).
The TMPL_VAR tag may also include an optional DEFAULT attribute that contains a
string that will be used if the variable returns false.
<TMPL_VAR foo DEFAULT="Foo was false">
CHOMPING¶
Chomping refers to the handling of whitespace immediately before and immediately
after template tags. By default, nothing happens to this whitespace. Modifiers
can be placed just inside the opening and just before the closing tags to
control this behavior.
Additionally, the PRE_CHOMP and POST_CHOMP configuration variables can be set
and will globally control all chomping behavior for tags that do not have
their own chomp modifier. PRE_CHOMP and POST_CHOMP can be set to any of the
following values:
none: 0 + Template::Constants::CHOMP_NONE
one: 1 - Template::Constants::CHOMP_ONE
collapse: 2 = Template::Constants::CHOMP_COLLAPSE
greedy: 3 ~ Template::Constants::CHOMP_GREEDY
- CHOMP_NONE
- Don't do any chomping. The "+" sign is used to
indicate CHOMP_NONE.
Hello.
[%+ "Hi." +%]
Howdy.
Would print:
Hello.
Hi.
Howdy.
- CHOMP_ONE (formerly known as CHOMP_ALL)
- Delete any whitespace up to the adjacent newline. The
"-" is used to indicate CHOMP_ONE.
Hello.
[%- "Hi." -%]
Howdy.
Would print:
Hello.
Hi.
Howdy.
- CHOMP_COLLAPSE
- Collapse adjacent whitespace to a single space. The
"=" is used to indicate CHOMP_COLLAPSE.
Hello.
[%= "Hi." =%]
Howdy.
Would print:
Hello. Hi. Howdy.
- CHOMP_GREEDY
- Remove all adjacent whitespace. The "~" is used
to indicate CHOMP_GREEDY.
Hello.
[%~ "Hi." ~%]
Howdy.
Would print:
Hello.Hi.Howdy.
CONFIGURATION¶
The following configuration variables are supported (in alphabetical order).
Note: for further discussion you can refer to the TT config documentation.
Items may be passed in upper or lower case. If lower case names are passed they
will be resolved to uppercase during the "new" method.
All of the variables in this section can be passed to the "new"
constructor.
my $obj = Template::Alloy->new(
VARIABLES => \%hash_of_variables,
AUTO_RESET => 0,
TRIM => 1,
POST_CHOMP => "=",
PRE_CHOMP => "-",
);
- ABSOLUTE
- Boolean. Default false. Are absolute paths allowed for
included files.
- ADD_LOCAL_PATH
- If true, allows calls include_filename to temporarily add
the directory of the current template being processed to the INCLUDE_PATHS
arrayref. This allows templates to refer to files in the local template
directory without specifying the local directory as part of the filename.
Default is 0. If set to a negative value, the current directory will be
added to the end of the current INCLUDE_PATHS.
This property may also be set in the template using the CONFIG directive.
[% CONFIG ADD_LOCAL_PATH => 1 %]
- ANYCASE
- Allow directive matching to be case insensitive.
[% get 23 %] prints 23 with ANYCASE => 1
- AUTO_RESET
- Boolean. Default 1. Clear blocks that were set during the
process method.
- AUTO_EVAL
- Boolean. Default 0 (default 1 in Velocity syntax). If set
to true, double quoted strings will automatically be passed to the eval
filter. This configurtation option may also be passed to the CONFIG
directive.
- AUTO_FILTER
- Can be the name of any filter. Default undef. Any variable
returned by a GET directive (including implicit GET) will be passed to the
named filter. This configurtation option may also be passed to the CONFIG
directive.
# with AUTO_FILTER => 'html'
[% f = "&"; GET f %] prints &
[% f = "&"; f %] prints & (implicit GET)
If a variable already has another filter applied the AUTO_FILTER is not
applied. The "none" scalar virtual method has been added to
allow for using variables without reapplying filters.
# with AUTO_FILTER => 'html'
[% f = "&"; f | none %] prints &
[% f = "&"; g = f; g %] prints &
[% f = "&"; g = f; g | none %] prints & (because g = f is a SET directive)
[% f = "&"; g = GET f; g | none %] prints & (because the actual GET directive was called)
- BLOCKS
- Only available via when using the process interface.
A hashref of blocks that can be used by the process method.
BLOCKS => {
block_1 => sub { ... }, # coderef that returns a block
block_2 => 'A String', # simple string
},
Note that a Template::Document cannot be supplied as a value (TT supports
this). However, it is possible to supply a value that is equal to the
hashref returned by the load_template method.
- CACHE_SIZE
- Number of compiled templates to keep in memory. Default
undef. Undefined means to allow all templates to cache. A value of 0 will
force no caching. The cache mechanism will clear templates that have not
been used recently.
- CACHE_STR_REFS
- Default 1. If set, any string refs will have an MD5 sum
taken that will then be used for caching the document - both in memory and
on the file system (if configured). This will give a significant speed
boost. Note that this affects strings passed to the EVALUATE directive or
eval filters as well. It may be set using the CONFIG directive.
- CALL_CONTEXT (Not in TT)
- Can be one of 'item', 'list', or 'smart'. The default type
is 'smart'. The CALL_CONTEXT configuration specifies in what Perl context
coderefs and methods used in the processed templates will be called. TT
historically has avoided the distinction of item (scalar) vs list context.
To avoid worrying about this, TT introduced 'smart' context. The
"@()" and "$()" context specifiers make it easier to
use CALL_CONTEXT in some situations.
The following table shows the relationship between the various contexts:
return values smart context list context item context
------------- ------------- ------------ ------------
A 'foo' 'foo' ['foo'] 'foo'
B undef undef [undef] undef
C (no return value) undef [] undef
D (7) 7 [7] 7
E (7,8,9) [7,8,9] [7,8,9] 9
F @a = (7) 7 [7] 1
G @a = (7,8,9) [7,8,9] [7,8,9] 3
H ({b=>"c"}) {b=>"c"} [{b=>"c"}] {b=>"c"}
I ([1]) [1] [[1]] [1]
J ([1],[2]) [[1],[2]] [[1],[2]] [2]
K [7,8,9] [7,8,9] [[7,8,9]] [7,8,9]
L (undef, "foo") die "foo" [undef, "foo"] "foo"
M wantarray?1:0 1 [1] 0
Cases F, H, I and M are common sticking points of the smart context in TT2.
Note that list context always returns an arrayref from a method or
function call. Smart context can give confusing results sometimes,
especially the I and J cases. Case L for smart match is very surprising.
The list and item context provide another feature for method calls. In smart
context, TT will look for a hash key in the object by the same name as the
method, if a method by that name doesn't exist. In item and list context
Alloy will die if a method by that name cannot be found.
The CALL_CONTEXT configuration item can be passed to new or it may also be
set during runtime using the CONFIG directive. The following method call
would be in list context:
[% CONFIG CALL_CONTEXT => 'list';
results = my_obj.get_results;
CONFIG CALL_CONTEXT => 'smart'
%]
Note that we needed to restore CALL_CONTEXT to the default 'smart' value.
Template::Alloy has added the "@()" (list) and the
"$()" (item) context specifiers. The previous example could be
written as:
[% results = @( my_obj.get_results ) %]
To call that same method in item (scalar) context you would do the
following:
[% results = $( my_obj.get_results ) %]
The "@()" and "$()" operators are based on the Perl 6
counterpart.
- COMPILE_DIR
- Base directory to store compiled templates. Default undef.
Compiled templates will only be stored if one of COMPILE_DIR and
COMPILE_EXT is set.
If set, the AST of parsed documents will be cached. If COMPILE_PERL is set,
the compiled perl code will also be stored.
- COMPILE_EXT
- Extension to add to stored compiled template filenames.
Default undef.
If set, the AST of parsed documents will be cached. If COMPILE_PERL is set,
the compiled perl code will also be stored.
- COMPILE_PERL
- Default false.
If set to 1 or 2, will translate the normal AST into a perl 5 code document.
This document can then be executed directly, cached in memory, or cached
on the file system depending upon the configuration items set.
If set to 1, a perl code document will always be generated.
If set to 2, a perl code document will only be generated if an AST has
already been cached for the document. This should give a speed benefit and
avoid extra compilation unless the document has been used more than once.
If Alloy is running in a cached environment such as mod_perl, then using
compile_perl can offer some speed benefit and makes Alloy faster than
Text::Tmpl and as fast as HTML::Template::Compiled (but Alloy has more
features).
If you are not running in a cached environment, such as from commandline, or
from CGI, it is generally faster to only run from the AST (with
COMPILE_PERL => 0).
- CONSTANTS
- Hashref. Used to define variables that will be
"folded" into the compiled template. Variables defined here
cannot be overridden.
CONSTANTS => {my_constant => 42},
A template containing:
[% constants.my_constant %]
Will have the value 42 compiled in.
Constants defined in this way can be chained as in [% constant.foo.bar.baz
%].
- CONSTANT_NAMESPACE
- Allow for setting the top level of values passed in
CONSTANTS. Default value is 'constants'.
- DEBUG
- Takes a list of constants |'ed together which enables
different debugging modes. Alternately the lowercase names may be used
(multiple values joined by a ",").
The only supported TT values are:
DEBUG_UNDEF (2) - debug when an undefined value is used (now easier to use STRICT)
DEBUG_DIRS (8) - debug when a directive is used.
DEBUG_ALL (2047) - turn on all debugging.
Either of the following would turn on undef and directive debugging:
DEBUG => 'undef, dirs', # preferred
DEBUG => 2 | 8,
DEBUG => DEBUG_UNDEF | DEBUG_DIRS, # constants from Template::Constants
- DEBUG_FORMAT
- Change the format of messages inserted when DEBUG has
DEBUG_DIRS set on. This essentially the same thing as setting the format
using the DEBUG directive.
- DEFAULT
- The name of a default template file to use if the passed
one is not found.
- DELIMITER
- String to use to split INCLUDE_PATH with. Default is :. It
is more straight forward to just send INCLUDE_PATH an arrayref of
paths.
- DUMP
- Configures the behavior of the DUMP tag. May be set to 0, a
hashref, or another true value. Default is true.
If set to 0, all DUMP directives will do nothing. This is useful if you
would like to turn off the DUMP directives under some environments.
IF set to a true value (or undefined) then DUMP directives will operate.
If set to a hashref, the values of the hash can be used to configure the
operation of the DUMP directives. The following are the values that can be
set in this hash.
- EntireStash
- Default 1. If set to 0, then the DUMP directive will not
print the entire contents of the stash when a DUMP directive is called
without arguments.
- handler
- Defaults to an internal coderef. If set to a coderef, the
DUMP directive will pass the arguments to be dumped and expects a string
with the dumped data. This gives complete control over the dump process.
Note 1: The default handler makes sure that values matching the private
variable regex are not included. If you install your own handler, you will
need to take care of these variables if you intend for them to not be
shown.
Note 2: If you would like the name of the variable to be dumped, include the
string '$VAR1' and the DUMP directive will interpolate the value. For
example, to dump all output as YAML - you could do the following:
DUMP => {
handler => sub {
require YAML;
return "\$VAR1 =\n".YAML::Dump(shift);
},
}
- header
- Default 1. Controls whether a header is printed for each
DUMP directive. The header contains the file and line number the DUMP
directive was called from. If set to 0 the headers are disabled.
- html
- Defaults to 1 if $ENV{'REQUEST_METHOD'} is set - 0
otherwise. If set to 1, then the output of the DUMP directive is passed to
the html filter and encased in "pre" tags. If set to 0 no html
encoding takes place.
- Sortkeys, Useqq, Ident, Pad, etc
- Any of the Data::Dumper configuration items may be
passed.
- ENCODING
- Default undef. If set, and if Perl version is greater than
or equal to 5.7.3 (when Encode.pm was first included), then Encode::decode
will be called everytime a template file is processed and will be passed
the value of ENCODING and text from the template.
This item can also be set using [% CONFIG ENCODING => encoding %] before
calling INCLUDE or PROCESS directives to change encodings on the fly.
- END_TAG
- Set a string to use as the closing delimiter for TT.
Default is "%]".
- ERROR
- Used as a fall back when the processing of a template
fails. May either be a single filename that will be used in all cases, or
may be a hashref of options where the keynames represent error types that
will be handled by the filename in their value. A key named default will
be used if no other matching keyname can be found. The selection process
is similar to that of the TRY/CATCH/THROW directives (see those directives
for more information).
my $t = Template::Alloy->new({
ERROR => 'general/catch_all_errors.html',
});
my $t = Template::Alloy->new({
ERROR => {
default => 'general/catch_all_errors.html',
foo => 'catch_all_general_foo_errors.html',
'foo.bar' => 'catch_foo_bar_errors.html',
},
});
Note that the ERROR handler will only be used for errors during the
processing of the main document. It will not catch errors that occur in
templates found in the PRE_PROCESS, POST_PROCESS, and WRAPPER
configuration items.
- ERRORS
- Same as the ERROR configuration item. Both may be used
interchangably.
- EVAL_PERL
- Boolean. Default false. If set to a true value, PERL and
RAWPERL blocks will be allowed to run. This is a potential security hole,
as arbitrary perl can be included in the template. If Template::Toolkit is
installed, a true EVAL_PERL value also allows the perl and evalperl
filters to be used.
- FILTERS
- Allow for passing in TT style filters.
my $filters = {
filter1 => sub { my $str = shift; $s =~ s/./1/gs; $s },
filter2 => [sub { my $str = shift; $s =~ s/./2/gs; $s }, 0],
filter3 => [sub { my ($context, @args) = @_; return sub { my $s = shift; $s =~ s/./3/gs; $s } }, 1],
};
my $str = q{
[% a = "Hello" %]
1 ([% a | filter1 %])
2 ([% a | filter2 %])
3 ([% a | filter3 %])
};
my $obj = Template::Alloy->new(FILTERS => $filters);
$obj->process(\$str) || die $obj->error;
Would print:
1 (11111)
2 (22222)
3 (33333)
Filters passed in as an arrayref should contain a coderef and a value
indicating if they are dynamic or static (true meaning dynamic). The
dynamic filters are passed the pseudo context object and any arguments and
should return a coderef that will be called as the filter. The filter
coderef is then passed the string.
- GLOBAL_CACHE
- Default 0. If true, documents will be cached in
$Template::Alloy::GLOBAL_CACHE. It may also be passed a hashref, in which
case the documents will be cached in the passed hashref.
The TT, Tmpl, and velocity will automatically cache documents in the object.
The HTML::Template interface uses a new object each time. Setting the
HTML::Template's CACHE configuration is the same as setting
GLOBAL_CACHE.
- INCLUDE_PATH
- A string or an arrayref or coderef that returns an arrayref
that contains directories to look for files included by processed
templates. Defaults to "." (the current directory).
- INCLUDE_PATHS
- Non-TT item. Same as INCLUDE_PATH but only takes an
arrayref. If not specified then INCLUDE_PATH is turned into an arrayref
and stored in INCLUDE_PATHS. Overrides INCLUDE_PATH.
- INTERPOLATE
- Boolean. Specifies whether variables in text portions of
the template will be interpolated. For example, the $variable and
${var.value} would be substituted with the appropriate values from the
variable cache (if INTERPOLATE is on).
[% IF 1 %]The variable $variable had a value ${var.value}[% END %]
- LOAD_PERL
- Indicates if the USE directive can fall back and try and
load a perl module if the indicated module was not found in the
PLUGIN_BASE path. See the USE directive. This configuration has no bearing
on the COMPILE_PERL directive used to indicate using compiled perl
documents.
- MAX_EVAL_RECURSE (Alloy only)
- Will use $Template::Alloy::MAX_EVAL_RECURSE if not present.
Default is 50. Prevents runaway on the following:
[% f = "[% f|eval %]" %][% f|eval %]
- MAX_MACRO_RECURSE (Alloy only)
- Will use $Template::Alloy::MAX_MACRO_RECURSE if not
present. Default is 50. Prevents runaway on the following:
[% MACRO f BLOCK %][% f %][% END %][% f %]
- NAMESPACE
- No Template::Namespace::Constants support. Hashref of
hashrefs representing constants that will be folded into the template at
compile time.
Template::Alloy->new(NAMESPACE => {constants => {
foo => 'bar',
}});
Is the same as
Template::Alloy->new(CONSTANTS => {
foo => 'bar',
});
Any number of hashes can be added to the NAMESPACE hash.
- NEGATIVE_STAT_TTL (Not in TT)
- Defaults to STAT_TTL which defaults to $STAT_TTL which
defaults to 1.
Similar to STAT_TTL - but represents the time-to-live seconds until a
document that was not found is checked again against the system for
modifications. Setting this number higher will allow for fewer file system
accesses. Setting it to a negative number will allow for the file system
to be checked every hit.
- NO_INCLUDES
- Default false. If true, calls to INCLUDE, PROCESS, WRAPPER
and INSERT will fail. This option is also available when using the process
method.
- OUTPUT
- Alternate way of passing in the output location for
processed templates. If process is not passed an output argument, it will
look for this value.
See the process method for a listing of possible values.
- OUTPUT_PATH
- Base path for files written out via the process method or
via the redirect and file filters. See the redirect virtual method and the
process method for more information.
- PLUGINS
- A hashref of mappings of plugin modules.
PLUGINS => {
Iterator => 'Template::Plugin::Iterator',
DBI => 'MyDBI',
},
See the USE directive for more information.
- PLUGIN_BASE
- Default value is Template::Plugin. The base module
namespace that template plugins will be looked for. See the USE directive
for more information. May be either a single namespace, or an arrayref of
namespaces.
- POST_CHOMP
- Set the type of chomping at the ending of a tag. See the
section on chomping for more information.
- POST_PROCESS
- Only available via when using the process interface.
A list of templates to be processed and appended to the content after the
main template. During this processing the "template" namespace
will contain the name of the main file being processed.
This is useful for adding a global footer to all templates.
- PRE_CHOMP
- Set the type of chomping at the beginning of a tag. See the
section on chomping for more information.
- PRE_DEFINE
- Same as the VARIABLES configuration item.
- PRE_PROCESS
- Only available via when using the process interface.
A list of templates to be processed before and pre-pended to the content
before the main template. During this processing the "template"
namespace will contain the name of the main file being processed.
This is useful for adding a global header to all templates.
- PROCESS
- Only available via when using the process interface.
Specify a file to use as the template rather than the one passed in to the
->process method.
- RECURSION
- Boolean. Default false. Indicates that INCLUDED or
PROCESSED files can refer to each other in a circular manner. Be careful
about recursion.
- RELATIVE
- Boolean. Default false. If true, allows filenames to be
specified that are relative to the currently running process.
- SEMICOLONS
- Boolean. Default fast. If true, then the syntax will
require that semi-colons separate multiple directives in the same tag.
This is useful for keeping the syntax a little more clean as well as
trouble shooting some errors.
- SHOW_UNDEFINED_INTERP (Not in TT)
- Default false (default true in Velocity). If INTERPOLATE is
true, interpolated dollar variables that return undef will be removed.
With SHOW_UNDEFINED_INTERP set, undef values will leave the variable
there.
[% CONFIG INTERPOLATE => 1 %]
[% SET foo = 1 %][% SET bar %]
($foo)($bar) ($!foo)($!bar)
Would print:
(1)() (1)()
But the following:
[% CONFIG INTERPOLATE => 1, SHOW_UNDEFINED_INTERP => 1 %]
[% SET foo = 1 %][% SET bar %]
($foo)($bar) ($!foo)($!bar)
Would print:
(1)($bar) (1)()
Note that you can use an exclamation point directly after the the dollar to
make the variable silent. This is similar to how Velocity works.
- START_TAG
- Set a string or regular expression to use as the opening
delimiter for TT. Default is "[%". You should be sure that the
tag does not include grouping parens or INTERPOLATE will not function
properly.
- STASH
- Template::Alloy manages its own stash of variables. You can
pass a Template::Stash or Template::Stash::XS object, but Template::Alloy
will copy all of values out of the object into its own stash.
Template::Alloy won't use any of the methods of the passed STASH object.
The STASH option is only available when using the process method.
- STAT_TTL
- Defaults to $STAT_TTL which defaults to 1. Represents
time-to-live seconds until a cached in memory document is compared to the
file system for modifications. Setting this number higher will allow for
fewer file system accesses. Setting it to a negative number will allow for
the file system to be checked every hit.
- STREAM
- Defaults to false. If set to true, generated template
content will be printed to the currently selected filehandle (default is
STDOUT) as soon as it is ready - there will be no buffering of the output.
The Stream role uses the Play role's directives (non-compiled_perl).
All directives and configuration work, except for the following
exceptions:
- CLEAR directive
- Because the output is not buffered - the CLEAR directive
would have no effect. The CLEAR directive will throw an error when STREAM
is on.
- TRIM configuration
- Because the output is not buffered - trim operations cannot
be played on the output buffers.
- WRAPPER configuration/directive
- The WRAPPER configuration and directive items effectively
turn off STREAM since the WRAPPERS are generated in reverse order and
because the content is inserted into the middle of the WRAPPERS. WRAPPERS
will still work, they just won't stream.
- VARIOUS errors
- Because the template is streaming, items that cause errors
my result in partially printed pages - since the error would occur part
way through the print.
All output is printed directly to the currently selected filehandle (defaults to
STDOUT) via the CORE::print function. Any output parameter passed to process
or process_simple will be ignored.
If you would like the output to go to another handle, you will need to select
that handle, process the template, and re-select STDOUT.
- STRICT
- Defaults to false. If set to true, any undefined variable
that is encountered will cause the processing of the template to abort.
This can be caught with a TRY block. This can be useful for making sure
that the template only attempts to use variables that were correctly
initialized similiar in spirit to Perl's "use strict."
When this occurs the strict_throw method is called.
See the STRICT_THROW configuration for additional options.
Similar functionality could be implemeted using UNDEFINED_ANY.
The STRICT configuration item can be passed to new or it may also be set
during runtime using the CONFIG directive. Once set though it cannot be
disabled for the duration of the current template and sub components. For
example you could call [% CONFIG STRICT => 1 %] in header.tt and strict
mode would be enabled for the header.tt and any sub templates processed by
header.tt.
- STRICT_THROW (not in TT)
- Default undef. Can be set to a subroutine which will be
called when STRICT is set and an undefined variable is processed. It will
be passed the error type, error message, and a hashref of template
information containing the current component being processed, the current
outer template being processed, the identity reference for the variable,
and the stringified name of the identity. This override can be used for
filtering allowable elements.
my $ta = Template::Alloy->new({
STRICT => 1,
STRICT_THROW => sub {
my ($ta, $err_type, $msg, $args) = @_;
return if $args->{'component'} eq 'header.tt'
&& $args->{'template'} eq 'main.html'
&& $args->{'name'} eq 'foo.bar(1)'; # stringified identity name
$ta->throw($err_type, $msg); # all other undefined variables die
},
});
- SYNTAX (not in TT)
- Defaults to "cet". Indicates the syntax that will
be used for parsing included templates or eval'ed strings. You can use the
CONFIG directive to change the SYNTAX on the fly (it will not affect the
syntax of the document currently being parsed).
The syntax may be passed in upper or lower case.
The available choices are:
alloy - Template::Alloy style - the same as TT3
tt3 - Template::Toolkit ver3 - same as Alloy
tt2 - Template::Toolkit ver2 - almost the same as TT3
tt1 - Template::Toolkit ver1 - almost the same as TT2
ht - HTML::Template - same as HTML::Template::Expr without EXPR
hte - HTML::Template::Expr
Passing in a different syntax allows for the process method to use a non-TT
syntax and for the output method to use a non-HT syntax.
The following is a sample of HTML::Template interface usage parsing a
Template::Toolkit style document.
my $obj = Template::Alloy->new(filename => 'my/template.tt'
syntax => 'cet');
$obj->param(\%swap);
print $obj->output;
The following is a sample of Template::Toolkit interface usage parsing a
HTML::Template::Expr style document.
my $obj = Template::Alloy->new(SYNTAX => 'hte');
$obj->process('my/template.ht', \%swap);
You can use the define_syntax method to add another custom syntax to the
list of available options.
- TAG_STYLE
- Allow for setting the type of tag delimiters to use for
parsing the TT. See the TAGS directive for a listing of the available
types.
- TRIM
- Remove leading and trailing whitespace from blocks and
templates. This operation is performed after all enclosed template tags
have been executed.
- UNDEFINED_ANY
- This is not a TT configuration option. This option expects
to be a code ref that will be called if a variable is undefined during a
call to play_expr. It is passed the variable identity array as a single
argument. This is most similar to the "undefined" method of
Template::Stash. It allows for the "auto-defining" of a variable
for use in the template. It is suggested that UNDEFINED_GET be used
instead as UNDEFINED_ANY is a little to general in defining variables.
You can also sub class the module and override the undefined_any
method.
- UNDEFINED_GET
- This is not a TT configuration option. This option expects
to be a code ref that will be called if a variable is undefined during a
call to GET. It is passed the variable identity array as a single
argument. This is more useful than UNDEFINED_ANY in that it is only called
during a GET directive rather than in embedded expressions (such as [% a
|| b || c %]).
You can also sub class the module and override the undefined_get
method.
- V1DOLLAR
- This allows for some compatibility with TT1 templates. The
only real behavior change is that [% $foo %] becomes the same as [% foo
%]. The following is a basic table of changes invoked by using V1DOLLAR.
With V1DOLLAR Equivalent Without V1DOLLAR (Normal default)
"[% foo %]" "[% foo %]"
"[% $foo %]" "[% foo %]"
"[% ${foo} %]" "[% ${foo} %]"
"[% foo.$bar %]" "[% foo.bar %]"
"[% ${foo.bar} %]" "[% ${foo.bar} %]"
"[% ${foo.$bar} %]" "[% ${foo.bar} %]"
"Text: $foo" "Text: $foo"
"Text: ${foo}" "Text: ${foo}"
"Text: ${$foo}" "Text: ${foo}"
- V2EQUALS
- Default 1 in TT syntaxes, defaults to 0 in HTML::Template
syntaxes.
If set to 1 then "==" is an alias for "eq" and "!=
is an alias for "ne".
[% CONFIG V2EQUALS => 1 %][% ('7' == '7.0') || 0 %]
[% CONFIG V2EQUALS => 0 %][% ('7' == '7.0') || 0 %]
Prints
0
1
- V2PIPE
- Restores the behavior of the pipe operator to be compatible
with TT2.
With V2PIPE = 1
[%- BLOCK a %]b is [% b %]
[% END %]
[%- PROCESS a b => 237 | repeat(2) %]
# output of block "a" with b set to 237 is passed to the repeat(2) filter
b is 237
b is 237
With V2PIPE = 0 (default)
[%- BLOCK a %]b is [% b %]
[% END %]
[% PROCESS a b => 237 | repeat(2) %]
# b set to 237 repeated twice, and b passed to block "a"
b is 237237
- VARIABLES
- A hashref of variables to initialize the template stash
with. These variables are available for use in any of the executed
templates. See the section on VARIABLES for the types of information that
can be passed in.
- VMETHOD_FUNCTIONS
- Defaults to 1. All scalar virtual methods are available as
top level functions as well. This is not true of TT2. In Template::Alloy
the following are equivalent:
[% "abc".length %]
[% length("abc") %]
You may set VMETHOD_FUNCTIONS to 0 to disable this behavior.
- WRAPPER
- Only available via when using the process interface.
Operates similar to the WRAPPER directive. The option can be given a single
filename, or an arrayref of filenames that will be used to wrap the
processed content. If an arrayref is passed the filenames are processed in
reverse order, so that the first filename specified will end up being on
the outside (surrounding all other wrappers).
my $t = Template::Alloy->new(
WRAPPER => ['my/wrappers/outer.html', 'my/wrappers/inner.html'],
);
Content generated by the PRE_PROCESS and POST_PROCESS will come before and
after (respectively) the content generated by the WRAPPER configuration
item.
See the WRAPPER direcive for more examples of how wrappers are
construted.
CONFIGURATION (HTML::Template STYLE)¶
The following HTML::Template and HTML::Template::Expr configuration variables
are supported (in HTML::Template documentation order). Note: for further
discussion you can refer to the HT documentation. Many of the variables
mentioned in the TT CONFIGURATION section apply here as well. Unless noted,
these items only apply when using the output method.
Items may be passed in upper or lower case. All passed items are resolved to
upper case.
These variables should be passed to the "new" constructor.
my $obj = Template::Alloy->new(
type => 'filename',
source => 'my/template.ht',
die_on_bad_params => 1,
loop_context_vars => 1,
global_vars => 1
post_chomp => "=",
pre_chomp => "-",
);
- TYPE
- Can be one of filename, filehandle, arrayref, or scalarref.
Indicates what type of input is in the "source" configuration
item.
- SOURCE
- Stores where to read the input file. The type is specified
in the "type" configuration item.
- FILENAME
- Indicates a filename to read the template from. Same as
putting the filename in the "source" item and setting
"type" to "filename".
Must be set to enable caching.
- FILEHANDLE
- Should contain an open filehandle to read the template
from. Same as putting the filehandle in the "source" item and
setting "type" to "filehandle".
Will not be cached.
- ARRAYREF
- Should contain an arrayref whose values are the lines of
the template. Same as putting the arrayref in the "source" item
and setting "type" to "arrayref".
Will not be cached.
- SCALARREF
- Should contain an reference to a scalar that contains the
template. Same as putting the scalar ref in the "source" item
and setting "type" to "scalarref".
Will not be cached.
- CACHE
- If set to one, then Alloy will use a global, in-memory
document cache to store compiled templates in between calls. This is
generally only useful in a mod_perl environment. The document is checked
for a different modification time at each request.
- BLIND_CACHE
- Same as with cache enabled, but will not check if the
document has been modified.
- FILE_CACHE
- If set to 1, will cache the compiled document on the file
system. If true, file_cache_dir must be set.
- FILE_CACHE_DIR
- The directory where to store cached documents when
file_cache is true. This is similar to the TT compile_dir option.
- DOUBLE_FILE_CACHE
- Uses a combination of file_cache and cache.
- PATH
- Same as INCLUDE_PATH when using the process method.
- ASSOCIATE
- May be a single CGI object or an arrayref of objects. The
params from these objects will be added to the params during the output
call.
- CASE_SENSITIVE
- Allow passed variables set through the param method, or the
associate configuration to be used case sensitively. Default is off. It is
highly suggested that this be set to 1.
- LOOP_CONTEXT_VARS
- Default false. When true, calls to the loop directive will
create the following variables that give information about the current
iteration of the loop:
__first__ - True on first iteration only
__last__ - True on last iteration only
__inner__ - True on any iteration that isn't first or last
__odd__ - True on odd iterations
__counter__ - The iteration count
These variables are also available to LOOPs run under TT syntax if
loop_context_vars is set and if QR_PRIVATE is set to 0.
- GLOBAL_VARS.
- Default true in HTE mode. Default false in HT. Allows top
level variables to be used in LOOPs. When false, only variables defined in
the current LOOP iteration hashref will be available.
- DEFAULT_ESCAPE
- Controls the type of escape used on named variables in
TMPL_VAR directives. Can be one of HTML, URL, or JS. The values of
TMPL_VAR directives will be encoded with this type unless they specify
their own type via an ESCAPE attribute.
You may alternately use the AUTO_FILTER directive which can be any of the
item vmethod filters (you must use lower case when specifying the
AUTO_FILTER directive). The AUTO_FILTER directive will also be applied to
TMPL_VAR EXPR and TMPL_GET items while DEFAULT_ESCAPE only applies to
TMPL_VAR NAME items.
- NO_TT
- Default false in 'hte' syntax. Default true in 'ht' syntax.
If true, no extended TT directives will be allowed.
The output method uses 'hte' syntax by default.
SEMI PUBLIC METHODS¶
The following list of methods are other interesting methods of Alloy that may be
re-implemented by subclasses of Alloy.
- "exception"
- Creates an exception object blessed into the package listed
in Template::Alloy::Exception.
- "execute_tree"
- Executes a parsed tree (returned from parse_tree)
- "play_expr"
- Play the parsed expression. Turns a variable identity array
into the parsed variable. This method is also responsible for playing
operators and running virtual methods and filters. The variable identity
array may also contain literal values, or operator identity arrays.
- "include_filename"
- Takes a file path, and resolves it into the full filename
using paths from INCLUDE_PATH or INCLUDE_PATHS.
- "_insert"
- Resolves the file passed, and then returns its
contents.
- "list_filters"
- Dynamically loads the filters list from Template::Filters
when a filter is used that is not natively implemented in Alloy.
- "load_template"
- Given a filename or a string reference will return a
"document" hashref hash that contains the parsed tree.
my $doc = $self->load_template($file); # errors die
This method handles the in-memory caching of the document.
- "load_tree"
- Given the "document" hashref, will either load
the parsed AST from file (if configured to do so), or will load the
content, parse the content using the Parse role, and will return the tree.
File based caching of the parsed AST happens here.
- "load_perl"
- Only used if COMPILE_PERL is true (default is false).
Given the "document" hashref, will either load the compiled perl
from file (if configured to do so), or will load the AST using
"load_tree", will compile a new perl code document using the
Compile role, and will return the perl code. File based caching of the
compiled perl happens here.
- "parse_tree"
- Parses the passed string ref with the appopriate template
syntax.
See Template::Alloy::Parse for more details.
- "parse_expr"
- Parses the passed string ref for a variable or expression.
See Template::Alloy::Parse for more details.
- "parse_args"
- See Template::Alloy::Parse for more details.
- "set_variable"
- Used to set a variable. Expects a variable identity array
and the value to set. It will autovifiy as necessary.
- "strict_throw"
- Called during processing of template when STRICT
configuration is set and an uninitialized variable is met. Arguments are
the variable identity reference. Will call STRICT_THROW configuration item
if set, otherwise will call throw with a useful message.
- "throw"
- Creates an exception object from the arguments and
dies.
- "undefined_any"
- Called during play_expr if a value is returned that is
undefined. This could be used to magically create variables on the fly.
This is similar to Template::Stash::undefined. It is suggested that
undefined_get be used instead. Default behavior returns undef. You may
also pass a coderef via the UNDEFINED_ANY configuration variable. Also,
you can try using the DEBUG => 'undef', configuration option which will
throw an error on undefined variables.
- "undefined_get"
- Called when a variable is undefined during a GET directive.
This is useful to see if a value that is about to get inserted into the
text is undefined. undefined_any is a little too general for most cases.
Also, you may pass a coderef via the UNDEFINED_GET configuration
variable.
OTHER UTILITY METHODS¶
The following is a brief list of other methods used by Alloy. Generally, these
shouldn't be overwritten by subclasses.
- "ast_string"
- Returns perl code representation of a variable.
- "context"
- Used to create a "pseudo" context object that
allows for portability of TT plugins, filters, and perl blocks that need a
context object. Uses the Template::Alloy::Context class.
- "debug_node"
- Used to get debug info on a directive if DEBUG_DIRS is
set.
- "get_line_number_by_index"
- Used to turn string index position into line number
- "interpolate_node"
- Used for parsing text nodes for dollar variables when
interpolate is on.
- "play_operator"
- Provided by the Operator role. Allows for playing an
operator AST.
See Template::Alloy::Operator for more details.
- "apply_precedence"
- Provided by the Parse role. Allows for parsed operator
array to be translated to a tree based upon operator precedence.
- "_process"
- Called by process and the PROCESS, INCLUDE and other
directives.
- "slurp"
- Reads contents of passed filename - throws file exception
on error.
- "split_paths"
- Used to split INCLUDE_PATH or other directives if an
arrayref is not passed.
- "tt_var_string"
- Returns a template toolkit representation of a
variable.
- "_vars"
- Return a reference to the current stash of variables. This
is currently only used by the pseudo context object and may disappear at
some point.
THANKS¶
Thanks to Andy Wardley for creating Template::Toolkit.
Thanks to Sam Tregar for creating HTML::Template.
Thanks to David Lowe for creating Text::Tmpl.
Thanks to the Apache Velocity guys.
Thanks to Ben Grimm for a patch to allow passing a parsed document to the
->process method.
Thanks to David Warring for finding a parse error in HTE syntax.
Thanks to Carl Franks for adding the base ENCODING support.
AUTHOR¶
Paul Seamons <paul at seamons dot com>
LICENSE¶
This module may be distributed under the same terms as Perl itself.