.\" Automatically generated by Pod::Man 2.27 (Pod::Simple 3.28)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  \*(C+ will
.\" give a nicer C++.  Capital omega is used to do unbreakable dashes and
.\" therefore won't be available.  \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
.    ds C`
.    ds C'
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.\"
.\" Avoid warning from groff about undefined register 'F'.
.de IX
..
.nr rF 0
.if \n(.g .if rF .nr rF 1
.if (\n(rF:(\n(.g==0)) \{
.    if \nF \{
.        de IX
.        tm Index:\\$1\t\\n%\t"\\$2"
..
.        if !\nF==2 \{
.            nr % 0
.            nr F 2
.        \}
.    \}
.\}
.rr rF
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "Template::Alloy::Operator 3pm"
.TH Template::Alloy::Operator 3pm "2013-08-23" "perl v5.18.1" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
Template::Alloy::Operator \- Operator role.
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The Template::Alloy::Operator role provides the regexes necessary for
Template::Alloy::Parse to parse operators and place them in their
appropriate precedence.  It also provides the play_operator method
which is used by Template::Alloy::Play and Template::Alloy::Compile
for playing out the stored operator ASTs.
.SH "ROLE METHODS"
.IX Header "ROLE METHODS"
.IP "play_operator" 4
.IX Item "play_operator"
Takes an operator \s-1AST\s0 in the form of
.Sp
.Vb 1
\&    [undef, \*(Aq+\*(Aq, 1, 2]
.Ve
.Sp
Essentially, all operators are stored in \s-1RPN\s0 notation with
a leading \*(L"undef\*(R" to disambiguate operators in a normal
Alloy expression \s-1AST.\s0
.IP "define_operator" 4
.IX Item "define_operator"
Used for defining new operators.
.Sp
See Template::Alloy for more details.
.SH "OPERATOR LIST"
.IX Header "OPERATOR LIST"
The following operators are available in Template::Alloy.  Except
where noted these are the same operators available in \s-1TT. \s0 They are
listed in the order of their precedence (the higher the precedence the
tighter it binds).
.ie n .IP """.""" 4
.el .IP "\f(CW.\fR" 4
.IX Item "."
The dot operator.  Allows for accessing sub-members, methods, or
virtual methods of nested data structures.
.Sp
.Vb 1
\&    my $obj\->process(\e$content, {a => {b => [0, {c => [34, 57]}]}}, \e$output);
\&
\&    [% a.b.1.c.0 %] => 34
.Ve
.Sp
Note: on access to hashrefs, any hash keys that match the sub key name
will be used before a virtual method of the same name.  For example if
a passed hash contained pair with a keyname \*(L"defined\*(R" and a value of
\&\*(L"2\*(R", then any calls to hash.defined(another_keyname) would always
return 2 rather than using the vmethod named \*(L"defined.\*(R"  To get around
this limitation use the \*(L"|\*(R" operator (listed next).  Also \- on objects
the \*(L".\*(R" will always try and call the method by that name.  To always
call the vmethod \- use \*(L"|\*(R".
.ie n .IP """|""" 4
.el .IP "\f(CW|\fR" 4
.IX Item "|"
The pipe operator.  Similar to the dot operator.  Allows for
explicit calling of virtual methods and filters (filters are \*(L"merged\*(R"
with virtual methods in Template::Alloy and \s-1TT3\s0) when accessing
hashrefs and objects.  See the note for the \*(L".\*(R" operator.
.Sp
The pipe character is similar to \s-1TT2\s0 in that it can be used in place
of a directive as an alias for \s-1FILTER. \s0 It similar to \s-1TT3\s0 in that it
can be used for virtual method access.  This duality is one source of
difference between Template::Alloy and \s-1TT2\s0 compatibility.  Templates
that have directives that end with a variable name that then use the
\&\*(L"|\*(R" directive to apply a filter will be broken as the \*(L"|\*(R" will be
applied to the variable name.
.Sp
The following two cases will do the same thing.
.Sp
.Vb 1
\&    [% foo | html %]
\&
\&    [% foo FILTER html %]
.Ve
.Sp
Though they do the same thing, internally, foo|html is stored as a
single variable while \*(L"foo \s-1FILTER\s0 html\*(R" is stored as the variable foo
which is then passed to the \s-1FILTER\s0 html.
.Sp
A \s-1TT2\s0 sample that would break in Template::Alloy or \s-1TT3\s0 is:
.Sp
.Vb 1
\&    [% PROCESS foo a = b | html %]
.Ve
.Sp
Under \s-1TT2\s0 the content returned by \*(L"\s-1PROCESS\s0 foo a = b\*(R" would all be
passed to the html filter.  Under Template::Alloy and \s-1TT3,\s0 b would
be passed to the html filter before assigning it to the variable \*(L"a\*(R"
before the template foo was processed.
.Sp
A simple fix is to do any of the following:
.Sp
.Vb 1
\&    [% PROCESS foo a = b FILTER html %]
\&
\&    [% | html %][% PROCESS foo a = b %][% END %]
\&
\&    [% FILTER html %][% PROCESS foo a = b %][% END %]
.Ve
.Sp
This shouldn't be too much hardship and offers the great return of disambiguating
virtual method access.
.ie n .IP """\e""" 4
.el .IP "\f(CW\e\fR" 4
.IX Item ""
Unary.  The reference operator.  Not well publicized in \s-1TT. \s0 Stores a reference
to a variable for use later.  Can also be used to \*(L"alias\*(R" long names.
.Sp
.Vb 1
\&    [% f = 7 ; foo = \ef ; f = 8 ; foo %] => 8
\&
\&    [% foo = \ef.g.h.i.j.k; f.g.h.i.j.k = 7; foo %] => 7
\&
\&    [% f = "abcd"; foo = \ef.replace("ab", "\-AB\-") ; foo %] => \-AB\-cd
\&
\&    [% f = "abcd"; foo = \ef.replace("bc") ; foo("\-BC\-") %] => a\-BC\-d
\&
\&    [% f = "abcd"; foo = \ef.replace ; foo("cd", "\-CD\-") %] => ab\-CD\-
.Ve
.ie n .IP """++ \-\-""" 4
.el .IP "\f(CW++ \-\-\fR" 4
.IX Item "++ --"
Pre and post increment and decrement.  My be used as either a prefix
or postfix operator.
.Sp
.Vb 1
\&    [% ++a %][% ++a %] => 12
\&
\&    [% a++ %][% a++ %] => 01
\&
\&    [% \-\-a %][% \-\-a %] => \-1\-2
\&
\&    [% a\-\- %][% a\-\- %] => 0\-1
.Ve
.ie n .IP """**  ^  pow""" 4
.el .IP "\f(CW**  ^  pow\fR" 4
.IX Item "** ^ pow"
Right associative binary.  X raised to the Y power.  This isn't available in \s-1TT 2.15.\s0
.Sp
.Vb 1
\&    [% 2 ** 3 %] => 8
.Ve
.ie n .IP """!""" 4
.el .IP "\f(CW!\fR" 4
.IX Item "!"
Prefix not.  Negation of the value.
.ie n .IP """\-""" 4
.el .IP "\f(CW\-\fR" 4
.IX Item "-"
Prefix minus.  Returns the value multiplied by \-1.
.Sp
.Vb 1
\&    [% a = 1 ; b = \-a ; b %] => \-1
.Ve
.ie n .IP """*""" 4
.el .IP "\f(CW*\fR" 4
.IX Item "*"
Left associative binary. Multiplication.
.ie n .IP """/  div  DIV""" 4
.el .IP "\f(CW/  div  DIV\fR" 4
.IX Item "/ div DIV"
Left associative binary. Division.  Note that / is floating point division, but div and
\&\s-1DIV\s0 are integer division.
.Sp
.Vb 2
\&   [% 10  /  4 %] => 2.5
\&   [% 10 div 4 %] => 2
.Ve
.ie n .IP """%  mod  MOD""" 4
.el .IP "\f(CW%  mod  MOD\fR" 4
.IX Item "% mod MOD"
Left associative binary. Modulus.
.Sp
.Vb 1
\&   [% 15 % 8 %] => 7
.Ve
.ie n .IP """+""" 4
.el .IP "\f(CW+\fR" 4
.IX Item "+"
Left associative binary.  Addition.
.ie n .IP """\-""" 4
.el .IP "\f(CW\-\fR" 4
.IX Item "-"
Left associative binary.  Minus.
.ie n .IP """_  ~""" 4
.el .IP "\f(CW_  ~\fR" 4
.IX Item "_ ~"
Left associative binary.  String concatenation.
.Sp
.Vb 1
\&    [% "a" ~ "b" %] => ab
.Ve
.ie n .IP """<  >  <=  >=""" 4
.el .IP "\f(CW<  >  <=  >=\fR" 4
.IX Item "< > <= >="
Non associative binary.  Numerical comparators.
.ie n .IP """lt  gt  le  ge""" 4
.el .IP "\f(CWlt  gt  le  ge\fR" 4
.IX Item "lt gt le ge"
Non associative binary.  String comparators.
.ie n .IP """eq""" 4
.el .IP "\f(CWeq\fR" 4
.IX Item "eq"
Non associative binary.  String equality test.
.ie n .IP """==""" 4
.el .IP "\f(CW==\fR" 4
.IX Item "=="
Non associative binary. In \s-1TT\s0 syntaxes the V2EQUALS configuration
item defaults to true which means this operator will operate
the same as the \*(L"eq\*(R" operator.  Setting V2EQUALS to 0 will
change this operator to mean numeric equality.  You could also use [% ! (a <=> b) %]
but that is a bit messy.
.Sp
The HTML::Template syntaxes default V2EQUALS to 0 which means
that it will test for numeric equality just as you would normally
expect.
.Sp
In either case \- you should always use \*(L"eq\*(R" when you mean \*(L"eq\*(R".
The V2EQUALS will most likely eventually default to 0.
.ie n .IP """ne""" 4
.el .IP "\f(CWne\fR" 4
.IX Item "ne"
Non associative binary.  String non-equality test.
.ie n .IP """!=""" 4
.el .IP "\f(CW!=\fR" 4
.IX Item "!="
Non associative binary. In \s-1TT\s0 syntaxes the V2EQUALS configuration
item defaults to true which means this operator will operate
the same as the \*(L"ne\*(R" operator.  Setting V2EQUALS to 0 will
change this operator to mean numeric non-equality.
You could also use [% (a <=> b) %] but that is a bit messy.
.Sp
The HTML::Template syntaxes default V2EQUALS to 0 which means
that it will test for numeric non-equality just as you would
normally expect.
.Sp
In either case \- you should always use \*(L"ne\*(R" when you mean \*(L"ne\*(R".
The V2EQUALS will most likely eventually default to 0.
.ie n .IP """<=>""" 4
.el .IP "\f(CW<=>\fR" 4
.IX Item "<=>"
Non associative binary.  Numeric comparison operator.  Returns \-1 if the first argument is
less than the second, 0 if they are equal, and 1 if the first argument is greater.
.ie n .IP """cmp""" 4
.el .IP "\f(CWcmp\fR" 4
.IX Item "cmp"
Non associative binary.  String comparison operator.  Returns \-1 if the first argument is
less than the second, 0 if they are equal, and 1 if the first argument is greater.
.ie n .IP """&&""" 4
.el .IP "\f(CW&&\fR" 4
.IX Item "&&"
Left associative binary.  And.  All values must be true.  If all values are true, the last
value is returned as the truth value.
.Sp
.Vb 1
\&    [% 2 && 3 && 4 %] => 4
.Ve
.ie n .IP """||""" 4
.el .IP "\f(CW||\fR" 4
.IX Item "||"
Right associative binary.  Or.  The first true value is returned.
.Sp
.Vb 1
\&    [% 0 || \*(Aq\*(Aq || 7 %] => 7
.Ve
.Sp
Note: perl is left associative on this operator \- but it doesn't matter because
|| has its own precedence level.  Setting it to right allows for Alloy to short
circuit earlier in the expression optree (left is (((1,2), 3), 4) while right
is (1, (2, (3, 4))).
.ie n .IP """//""" 4
.el .IP "\f(CW//\fR" 4
.IX Item "//"
Right associative binary.  Perl 6 err.  The first defined value is returned.
.Sp
.Vb 1
\&    [% foo // bar %]
.Ve
.ie n .IP """..""" 4
.el .IP "\f(CW..\fR" 4
.IX Item ".."
Non associative binary.  Range creator.  Returns an arrayref containing the values
between and including the first and last arguments.
.Sp
.Vb 1
\&    [% t = [1 .. 5] %] => variable t contains an array with 1,2,3,4, and 5
.Ve
.Sp
It is possible to place multiple ranges in the same [] constructor.  This is not available in \s-1TT.\s0
.Sp
.Vb 1
\&    [% t = [1..3, 6..8] %] => variable t contains an array with 1,2,3,6,7,8
.Ve
.Sp
The .. operator is the only operator that returns a list of items.
.ie n .IP """? :""" 4
.el .IP "\f(CW? :\fR" 4
.IX Item "? :"
Ternary \- right associative.  Can be nested with other ?: pairs.
.Sp
.Vb 2
\&    [% 1 ? 2 : 3 %] => 2
\&    [% 0 ? 2 : 3 %] => 3
.Ve
.ie n .IP """*= += \-= /= **= %= ~=""" 4
.el .IP "\f(CW*= += \-= /= **= %= ~=\fR" 4
.IX Item "*= += -= /= **= %= ~="
Self-modifying assignment \- right associative.  Sets the left hand side
to the operation of the left hand side and right (clear as mud).
In order to not conflict with \s-1SET, FOREACH\s0 and other operations, this
operator is only available in parenthesis.
.Sp
.Vb 2
\&   [% a = 2 %][%  a += 3  %] \-\-\- [% a %]    => \-\-\- 5   # is handled by SET
\&   [% a = 2 %][% (a += 3) %] \-\-\- [% a %]    => 5 \-\-\- 5
.Ve
.ie n .IP """=""" 4
.el .IP "\f(CW=\fR" 4
.IX Item "="
Assignment \- right associative.  Sets the left-hand side to the value of the righthand side.  In order
to not conflict with \s-1SET, FOREACH\s0 and other operations, this operator is only
available in parenthesis.  Returns the value of the righthand side.
.Sp
.Vb 2
\&   [%  a = 1  %] \-\-\- [% a %]    => \-\-\- 1   # is handled by SET
\&   [% (a = 1) %] \-\-\- [% a %]    => 1 \-\-\- 1
.Ve
.ie n .IP """not  NOT""" 4
.el .IP "\f(CWnot  NOT\fR" 4
.IX Item "not NOT"
Prefix. Lower precedence version of the '!' operator.
.ie n .IP """and  AND""" 4
.el .IP "\f(CWand  AND\fR" 4
.IX Item "and AND"
Left associative. Lower precedence version of the '&&' operator.
.ie n .IP """or OR""" 4
.el .IP "\f(CWor OR\fR" 4
.IX Item "or OR"
Right associative. Lower precedence version of the '||' operator.
.ie n .IP """err ERR""" 4
.el .IP "\f(CWerr ERR\fR" 4
.IX Item "err ERR"
Right associative.  Lower precedence version of the '//' operator.
.ie n .IP """\->"" (Not in \s-1TT2\s0)" 4
.el .IP "\f(CW\->\fR (Not in \s-1TT2\s0)" 4
.IX Item "-> (Not in TT2)"
Macro operator.  Works like the \s-1MACRO\s0 directive but can be used in
map, sort, and grep list operations.  Syntax is based on the Perl 6
pointy sub.  There are two differences from the \s-1MACRO\s0 directive.  First
is that if no argument list is specified, a default argument list with
a single parameter named \*(L"this\*(R" will be used.  Second, the \f(CW\*(C`\->\*(C'\fR
operator parses its block as if it was already in a template tag.
.Sp
.Vb 4
\&    [% foo = \->{ "Hi" } %][% foo %] => Hi
\&    [% foo = \->{ this.repeat(2) } %][% foo("Hi") %] => HiHi
\&    [% foo = \->(n){ n.repeat(2) } %][% foo("Hi") %] => HiHi
\&    [% foo = \->(a,b){ a; "|"; b } %][% foo(2,3) %]  => 2|3
\&
\&    [% [0..10].grep(\->{ this % 2 }).join %] => 1 3 5 7 9
\&    [% [\*(Aqa\*(Aq..\*(Aqc\*(Aq].map(\->{ this.upper }).join %] => A B C
\&
\&    [% [1,2,3].sort(\->(a,b){ b <=> a }).join %] prints 3 2 1
\&
\&    [% c = [{k => "wow"}, {k => "wee"}, {k => "a"}] %]
\&    [% c.sort(\->(a,b){ a.k cmp b.k }).map(\->{this.k}).join %] => a wee wow
.Ve
.Sp
Note: Care should be used when attempting to sort large lists.
The mini-language of Template::Alloy is a interpreted language running
in Perl which is an interpreted language.  There are likely to be
performance issues when trying to do low level functions such as sort
on large lists.
.Sp
The \s-1RETURN\s0 directive and return item, list, and hash vmethods can be
used to return more interesting values from a \s-1MACRO.\s0
.Sp
.Vb 3
\&  [% a = \->(n){ [1..n].return } %]
\&  [% a(3).join %]    => 1 2 3
\&  [% a(10).join %]   => 1 2 3 4 5 6 7 8 9 10
.Ve
.Sp
The Schwartzian transform is now possible in Template::Alloy (somebody
somewhere is rolling over in their grave).
.Sp
.Vb 5
\&  [%\- qw(Z a b D y M)
\&        .map(\->{ [this.lc, this].return })
\&        .sort(\->(a,b){a.0 cmp b.0})
\&        .map(\->{this.1})
\&        .join %]          => a b D M y Z
.Ve
.ie n .IP """{}""" 4
.el .IP "\f(CW{}\fR" 4
.IX Item "{}"
This operator is not exposed for external use.  It is used internally
by Template::Alloy to delay the creation of a hash until the
execution of the compiled template.
.ie n .IP """[]""" 4
.el .IP "\f(CW[]\fR" 4
.IX Item "[]"
This operator is not exposed for external use.  It is used internally
by Template::Alloy to delay the creation of an array until the
execution of the compiled template.
.ie n .IP """@()""" 4
.el .IP "\f(CW@()\fR" 4
.IX Item "@()"
List context specifier.  Methods or functions inside this operator
will always be called in list context and will always return an
arrayref of the results.  See the \s-1CALL_CONTEXT\s0 configuration
directive.
.ie n .IP """$()""" 4
.el .IP "\f(CW$()\fR" 4
.IX Item "$()"
Item context specifier.  Methods or functions inside this operator
will always be called in item (scalar) context.  See the \s-1CALL_CONTEXT\s0
configuration directive.
.ie n .IP """qr""" 4
.el .IP "\f(CWqr\fR" 4
.IX Item "qr"
This operator is not exposed for external use.  It is used internally
by Template::Alloy to store a regular expression and its options.
It will return a compiled Regexp object when compiled.
.ie n .IP """\-temp\-""" 4
.el .IP "\f(CW\-temp\-\fR" 4
.IX Item "-temp-"
This operator is not exposed for external use.  It is used internally
by some directives to pass temporary, literal data into play_expr
to allow additional vmethods or filters to be called on existing data.
.SH "AUTHOR"
.IX Header "AUTHOR"
Paul Seamons <paul@seamons.com>
.SH "LICENSE"
.IX Header "LICENSE"
This module may be distributed under the same terms as Perl itself.