Contents
Top- Scalar Virtual Methods
- chunk(size)
- collapse
- defined
- dquote
- hash
- lcfirst
- length
- list
- lower
- match(pattern, global)
- repeat(n)
- replace(search, replace)
- remove(pattern)
- search(pattern)
- size
- split(pattern)
- substr(offset, length, replacement)
- squote
- trim
- ucfirst
- upper
- Hash Virtual Methods
- keys
- values
- items
- each
- pairs
- list
- sort, nsort
- import
- defined, exists
- delete
- size
- item
- List Virtual Methods
- first, last
- size, max
- defined
- reverse
- join
- grep
- sort, nsort
- unshift(item), push(item)
- shift, pop
- unique
- import
- merge
- slice(from, to)
- splice(offset, length, list)
- hash
- Automagic Promotion of Scalar to List for Virtual Methods
- Defining Custom Virtual Methods
Scalar Virtual Methods
Topchunk(size)
TopSplits the value into a list of chunks of a certain size.
[% ccard_no = "1234567824683579";
ccard_no.chunk(4).join
%]
Output:
1234 5678 2468 3579
If the size is specified as a negative number then the text will be chunked from right-to-left. This gives the correct grouping for numbers, for example.
[% number = 1234567;
number.chunk(-3).join(',')
%]
Output:
1,234,567
collapse
TopReturns the text with any leading and trailing whitespace removed and any internal sequences of whitespace converted to a single space
[% text = " The bird\n is the word" %] [% text.collapse %] # The bird is the word
defined
TopReturns true if the value is defined.
[% user = get_user(uid) IF uid.defined %]
dquote
TopReturns the text with any double quote characters escaped with a backslash prefix. Any newline characters in the text will be replaced with "\n".
[% quote = 'He said "Oh really?"' %] [% quote.dquote %] # He said \"Oh really?\"
hash
Top
Return the value as a hash reference containing a single entry with the
key value
indicating the original scalar value. As with the
list
virtual method, this is generally used to help massage
data into different formats.
lcfirst
TopReturns the text with the first letter converted to lower case.
[% word = 'BIRD' %] [% word.lcfirst %] # bIRD
length
TopReturns the length of the string representation of the item:
[% IF password.length < 8 %] Password too short, dumbass! [% END %]
list
Top
Return the value as a single element list. This can be useful if you have
a variable which may contain a single item or a list and you want to
treat them equally. The list
method can be called against a
list reference and will simply return the original reference, effectively
a no-op.
[% thing.list.size %] # thing can be a scalar or a list
lower
TopReturns the text in lower case.
[% word = 'BIRD' %] [% word.lower %] # bird
match(pattern, global)
TopPerforms a regular expression match on the string using the pattern passed as an argument. If the pattern matches the string then the method returns a reference to a list of any strings captured within parenthesis in the pattern.
[% name = 'Larry Wall' %] [% matches = name.match('(\w+) (\w+)') %] [% matches.1 %], [% matches.0 %] # Wall, Larry
If the pattern does not match then the method returns false, rather than returning an empty list which Perl and the Template Toolkit both consider to be a true value. This allows you to write expression like this.
[% "We're not worthy!" IF name.match('Larry Wall') %] [% IF (matches = name.match('(\w+) (\w+)')) %] pattern matches: [% matches.join(', ') %] [% ELSE %] pattern does not match [% END %]
Any regex modifiers, like /s
, should be added in the regex
using the (?s)
syntax. For example, to modify the regex to
disregard whitespace (the /x
switch), use:
[% re = '(?x)
(\w+)
[ ]
(\w+)
';
matches = name.match(re);
%]
To perform a global search to match the pattern as many times as it
appears in the source string, provide a true value for the
global
argument following the pattern.
[% text = 'bandanna';
text.match('an+', 1).join(', ) # an, ann
%]
repeat(n)
TopRepeat the string a specified number of times.
[% name = 'foo' %] [% name.repeat(3) %] # foofoofoo
replace(search, replace)
TopOutputs the string with all instances of the first argument (specified as a Perl regular expression) with the second.
[% name = 'foo, bar & baz' %] [% name.replace('\W+', '_') %] # foo_bar_baz
You can use $1
, $2
, etc., to reference captured
parts (in parentheses) in the regular expression. Just be careful to
single quote the replacement string. If you use double
quotes then TT will try and interpolate the variables before passing the
string to the replace
vmethod.
[% name = 'FooBarBaz' %] [% name.replace('([A-Z])', ' $1') %] # Foo Bar Baz
remove(pattern)
TopOutputs the string with all instances of the pattern (specified as a Perl regular expression) removed.
[% name = 'foo, bar & baz' %] [% name.remove('\W+') %] # foobarbaz
search(pattern)
TopPerforms a similar function to match but simply returns true if the string matches the regular expression pattern passed as an argument.
[% name = 'foo bar baz' %] [% name.search('bar') ? 'bar' : 'no bar' %] # bar
This virtual method is now deprecated in favour of match. Move along now, there's nothing more to see here.
size
TopAlways returns 1 for scalar values. This method is provided for consistency with the hash and list size methods.
split(pattern)
Top
Calls Perl's split()
function to split a string into a list
of strings.
[% FOREACH dir IN mypath.split(':') %] [% dir %] [% END %]
substr(offset, length, replacement)
Top
Returns a substring starting at offset
, for
length
characters.
[% str 'foo bar baz wiz waz woz') %] [% str.substr(4, 3) %] # bar
If length
is not specified then it returns everything from
the offset
to the end of the string.
[% str.substr(12) %] # wiz waz woz
If both length
and replacement
are specified,
then the method replaces everything from offset
for
length
characters with $replacement
. The
substring removed from the string is then returned.
[% str.substr(0, 11, 'FOO') %] # foo bar baz [% str %] # FOO wiz waz woz
squote
TopReturns the text with any single quote characters escaped with a backslash prefix.
[% tim = "Tim O'Reilly" %] [% tim.squote %] # Tim O\'Reilly
trim
TopReturns the text with any leading and trailing whitespace removed.
[% text = ' hello world ' %] [% text.trim %] # hello world
ucfirst
TopReturns the text with the first letter converted to upper case.
[% word = 'bird' %] [% word.ucfirst %] # Bird
upper
TopReturns the text in upper case.
[% word = 'bird' %] [% word.upper %] # BIRD
Hash Virtual Methods
Topkeys
TopReturns a list of keys in the hash. They are not returned in any particular order, but the order is the same as for the corresponding values method.
[% FOREACH key IN hash.keys %] * [% key %] [% END %]
If you want the keys in sorted order, use the list sort
method.
[% FOREACH key IN hash.keys.sort %] * [% key %] [% END %]
Having got the keys in sorted order, you can then use variable
interpolation to fetch the value. This is shown in the following example
by the use of $key
to fetch the item from hash
whose key is stored in the key
variable.
[% FOREACH key IN hash.keys.sort %] * [% key %] = [% hash.$key %] [% END %]
Alternately, you can use the pairs
method to get a list of
key/value pairs in sorted order.
values
Top
Returns a list of the values in the hash. As with the keys
method, they are not returned in any particular order, although it is the
same order that the keys are returned in.
[% hash.values.join(', ') %]
items
TopReturns a list of both the keys and the values expanded into a single list.
[% hash = {
a = 10
b = 20
};
hash.items.join(', ') # a, 10, b, 20
%]
each
Top
This method currently returns the same thing as the items
method.
However, please note that this method will change in the next major
version of the Template Toolkit (v3) to return the same thing as the
pairs
method. This will be done in an effort to make these
virtual method more consistent with each other and how Perl works.
In anticipation of this, we recommend that you stop using
hash.each
and instead use hash.items
.
pairs
TopThis method returns a list of key/value pairs. They are returned in sorted order according to the keys.
[% FOREACH pair IN product.pairs %] * [% pair.key %] is [% pair.value %] [% END %]
list
Top
Returns the contents of the hash in list form. An argument can be passed
to indicate the desired items required in the list: keys
to
return a list of the keys (same as hash.keys
),
values
to return a list of the values (same as
hash.values
), each
to return as list of key and
values (same as hash.each
), or pairs
to return
a list of key/value pairs (same as hash.pairs
).
[% keys = hash.list('keys') %] [% values = hash.list('values') %] [% items = hash.list('each') %] [% pairs = hash.list('pairs') %]
When called without an argument it currently returns the same thing as
the pairs
method. However, please note that this method will
change in the next major version of the Template Toolkit (v3) to return a
reference to a list containing the single hash reference (as per the
scalar list method).
In anticipation of this, we recommend that you stop using
hash.list
and instead use hash.pairs
.
sort, nsort
Top
Return a list of the keys, sorted alphabetically (sort
) or
numerically (nsort
) according to the corresponding values in
the hash.
[% FOREACH n IN phones.sort %] [% phones.$n %] is [% n %], [% END %]
import
Top
The import
method can be called on a hash array to import
the contents of another hash array.
[% hash1 = { foo = 'Foo' bar = 'Bar' } hash2 = { wiz = 'Wiz' woz = 'Woz' } %] [% hash1.import(hash2) %] [% hash1.wiz %] # Wiz
You can also call the import()
method by itself to import a
hash array into the current namespace hash.
[% user = { id => 'lwall', name => 'Larry Wall' } %] [% import(user) %] [% id %]: [% name %] # lwall: Larry Wall
defined, exists
TopReturns a true or false value if an item in the hash denoted by the key passed as an argument is defined or exists, respectively.
[% hash.defined('somekey') ? 'yes' : 'no' %] [% hash.exists('somekey') ? 'yes' : 'no' %]
When called without any argument, hash.defined
returns true
if the hash itself is defined (e.g. the same effect as
scalar.defined
).
delete
TopDelete one or more items from the hash.
[% hash.delete('foo', 'bar') %]
size
TopReturns the number of key/value pairs in the hash.
item
TopReturns an item from the hash using a key passed as an argument.
[% hash.item('foo') %] # same as hash.foo
List Virtual Methods
Topfirst, last
TopReturns the first/last item in the list. The item is not removed from the list.
[% results.first %] to [% results.last %]
If either is given a numeric argument n
, they return the
first or last n
elements:
The first 5 results are [% results.first(5).join(", ") %].
size, max
TopReturns the size of a list (number of elements) and the maximum index number (size - 1), respectively.
[% results.size %] search results matched your query
defined
TopReturns a true or false value if the item in the list denoted by the argument is defined.
[% list.defined(3) ? 'yes' : 'no' %]
When called without any argument, list.defined
returns true
if the list itself is defined (e.g. the same effect as
scalar.defined
).
reverse
TopReturns the items of the list in reverse order.
[% FOREACH s IN scores.reverse %] ... [% END %]
join
Top
Joins the items in the list into a single string, using Perl's
join()
function.
[% items.join(', ') %]
grep
TopReturns a list of the items in the list that match a regular expression pattern.
[% FOREACH directory.files.grep('\.txt$') %] ... [% END %]
sort, nsort
Top
Returns the items in alpha (sort
) or numerical
(nsort
) order.
[% library = books.sort %]
An argument can be provided to specify a search key. Where an item in the list is a hash reference, the search key will be used to retrieve a value from the hash which will then be used as the comparison value. Where an item is an object which implements a method of that name, the method will be called to return a comparison value.
[% library = books.sort('author') %]
In the example, the books
list can contains hash references
with an author
key or objects with an author
method.
You can also specify multiple sort keys.
[% library = books.sort('author', 'title') %]
In this case the books will be sorted primarily by author. If two or more books have authors with the same name then they will be sorted by title.
unshift(item), push(item)
Top
The push()
method adds an item or items to the end of list.
[% mylist.push(foo) %] [% mylist.push(foo, bar) %]
The unshift()
method adds an item or items to the start of a
list.
[% mylist.unshift(foo) %] [% mylist.push(foo, bar) %]
shift, pop
TopRemoves the first/last item from the list and returns it.
[% first = mylist.shift %] [% last = mylist.pop %]
unique
TopReturns a list of the unique elements in a list, in the same order as in the list itself.
[% mylist = [ 1, 2, 3, 2, 3, 4, 1, 4, 3, 4, 5 ] %] [% numbers = mylist.unique %]
While this can be explicitly sorted, it is not required that the list be sorted before the unique elements are pulled out (unlike the Unix command line utility).
[% numbers = mylist.unique.sort %]
import
TopAppends the contents of one or more other lists to the end of the current list.
[% one = [ 1 2 3 ];
two = [ 4 5 6 ];
three = [ 7 8 9 ];
one.import(two, three);
one.join(', ); # 1, 2, 3, 4, 5, 6, 7, 8, 9
%]
merge
TopReturns a list composed of zero or more other lists:
[% list_one = [ 1 2 3 ];
list_two = [ 4 5 6 ];
list_three = [ 7 8 9 ];
list_four = list_one.merge(list_two, list_three);
%]
The original lists are not modified.
slice(from, to)
Top
Returns a slice of items in the list between the bounds passed as
arguments. If the second argument, to
, isn't specified, then
it defaults to the last item in the list. The original list is not
modified.
[% first_three = list.slice(0,2) %] [% last_three = list.slice(-3, -1) %]
splice(offset, length, list)
Top
Behaves just like Perl's splice()
function allowing you to
selectively remove and/or replace elements in a list. It removes
length
items from the list, starting at offset
and replaces them with the items in list
.
[% play_game = [ 'play', 'scrabble' ];
ping_pong = [ 'ping', 'pong' ];
redundant = play_game.splice(1, 1, ping_pong);
redundant.join; # scrabble
play_game.join; # play ping pong
%]
The method returns a list of the items removed by the splice. You can use
the CALL
directive to ignore the output if you're not
planning to do anything with it.
[% CALL play_game.splice(1, 1, ping_pong) %]
As well as providing a reference to a list of replacement values, you can pass in a list of items.
[% CALL list.splice(-1, 0, 'foo', 'bar') %]
Be careful about passing just one item in as a replacement value. If it is a reference to a list then the contents of the list will be used. If it's not a list, then it will be treated as a single value. You can use square brackets around a single item if you need to be explicit:
[% # push a single item, an_item
CALL list.splice(-1, 0, an_item);
# push the items from another_list
CALL list.splice(-1, 0, another_list);
# push a reference to another_list
CALL list.splice(-1, 0, [ another_list ]);
%]
hash
TopReturns a reference to a hash array comprised of the elements in the list. The even-numbered elements (0, 2, 4, etc) become the keys and the odd-numbered elements (1, 3, 5, etc) the values.
[% list = ['pi', 3.14, 'e', 2.718] %] [% hash = list.hash %] [% hash.pi %] # 3.14 [% hash.e %] # 2.718
If a numerical argument is provided then the hash returned will have keys generated for each item starting at the number specified.
[% list = ['beer', 'peanuts'] %] [% hash = list.hash(1) %] [% hash.1 %] # beer [% hash.2 %] # peanuts
Automagic Promotion of Scalar to List for Virtual Methods
TopIn addition to the scalar virtual methods listed in the previous section, you can also call any list virtual method against a scalar. The item will be automagically promoted to a single element list and the appropriate list virtual method will be called.
One particular benefit of this comes when calling subroutines or object methods that return a list of items, rather than the preferred reference to a list of items. In this case, the Template Toolkit automatically folds the items returned into a list.
The upshot is that you can continue to use existing Perl modules or code
that returns lists of items, without having to refactor it just to keep
the Template Toolkit happy (by returning references to list).
Class::DBI
module is just one example of a particularly
useful module which returns values this way.
If only a single item is returned from a subroutine then the Template Toolkit assumes it meant to return a single item (rather than a list of 1 item) and leaves it well alone, returning the single value as it is. If you're executing a database query, for example, you might get 1 item returned, or perhaps many items which are then folded into a list.
The FOREACH
directive will happily accept either a list or a
single item which it will treat as a list. So it's safe to write
directives like this, where we assume that the something
variable is bound to a subroutine which may return one or more items:
[% FOREACH item IN something %] ... [% END %]
The automagic promotion of scalars to single item lists means that you can also use list virtual methods safely, even if you only get one item returned. For example:
[% something.first %] [% something.join %] [% something.reverse.join(', ') %]
Note that this is very much a last-ditch behaviour. If the single item
return is an object with a first
method, for example, then
that will be called, as expected, in preference to the list virtual
method.
Defining Custom Virtual Methods
Top
You can define your own virtual methods for scalars, lists and hash
arrays. The Template::Stash package variables $SCALAR_OPS
,
$LIST_OPS
and $HASH_OPS
are references to hash
arrays that define these virtual methods. HASH_OPS
and
LIST_OPS
methods are subroutines that accept a hash/list
reference as the first item. SCALAR_OPS
are subroutines that
accept a scalar value as the first item. Any other arguments specified
when the method is called will be passed to the subroutine.
# load Template::Stash to make method tables visible use Template::Stash; # define list method to return new list of odd numbers only $Template::Stash::LIST_OPS->{ odd } = sub { my $list = shift; return [ grep { $_ % 2 } @$list ]; };
Example template:
[% primes = [ 2, 3, 5, 7, 9 ] %] [% primes.odd.join(', ') %] # 3, 5, 7, 9
TODO: document the define_vmethod() method which makes this even easier