++ed by:
SANKO STAUGAARD

2 PAUSE users

Sanko Robinson
and 1 contributors

NAME

Template::Liquid::Condition - Basic Relational, Equality, and Content Operators

Description

These operators evaluate to true/false values. This is used internally but since you're here... might as well skim it. Nothing new to most people.

Relational Operators

If you're familiar with basic math, you already understand these.

Any of the following operators can be combined with logical and and or:

    5 > 2 and 'okay' contains 'ok' # true
    4 > 6 or 4 < 6                 # true ...silly, but true
    # where x = [1 .. 10]
    x contains 3 and x contains 0  # false

Binary and performs a short-circuit logical AND operation. That is, if the left operand is false, the right operand is not even evaluated. Likewise, binary or performs a short-circuit logical OR operation. That is, if the left operand is true, the right operand is not even evaluated.

>

Binary operator which returns true if the left argument is numerically less than the right argument.

Given...

    3 > 4  # false
    4 > 3  # true
    # where x == 10 and y == 12
    x > y  # false
    y > x  # true
    x > 3  # true
    x > x  # false

<

Binary operator which returns true if the left argument is numerically greater than the right argument.

Given...

    3 < 4   # true
    4 < 3   # false
    # where x == 10 and y == 12
    x < y   # true
    y < x   # false
    x < 30  # true
    x < x   # false

==

Binary operator which returns true if the left argument is numerically equal to the right argument.

    # where x == 10 and y == 12
    x == y   # false
    x == 10  # true
    y == y   # true

!=

Binary operator which returns true if the left argument is numerically not equal to the right argument.

    # where x == 10 and y == 12
    x != y  # true
    5 != 5  # false

eq

Binary operator which returns true if the left argument is stringwise equal to the right argument.

    'test' eq 'test'   # true
    'test' eq 'reset'  # false
    # where x  = 'cool beans'
    x eq 'awesome'     # false
    x eq 'Cool beans'  # false
    x eq 'cool beans'  # true
    x eq x             # true

ne

Binary operator which returns true if the left argument is stringwise not equal to the right argument.

    'test' ne 'test'   # false
    'test' ne 'reset'  # true
    # where x  = 'cool beans'
    x ne 'awesome'     # true
    x ne 'Cool beans'  # true
    x ne 'cool beans'  # false
    x ne x             # false

lt

Binary operator which returns true if the left argument is stringwise less than the right argument.

    'a' lt 'c'  # true
    'A' lt 'a'  # true
    # where x  = 'q'
    x lt 'r'    # true
    x lt 'm'    # false
    x lt x      # false

gt

Binary operator which returns true if the left argument is stringwise greater than the right argument.

    'a' gt 'c'  # false
    'A' gt 'a'  # false
    # where x  = 'q'
    x gt 'r'    # false
    x gt 'm'    # true
    x gt x      # true

Other Operators

These are nice things to have around...

contains

The contains operator is context sensitive.

Strings

If the variable on the left is a string, this operator searches the string for a pattern match, and (as if in scalar context) returns true if it succeeds, false if it fails.

Note that this is a simple $x =~ qr[${y}] match. Case matters.

Given...

    # where x = 'The Angels have the police box!'
    x contains 'police'       # true
    x contains 'Police'       # false
    x contains 'police box?'  # false
    x contains 'police box!'  # true
    x contains x              # true

Lists

If the variable is a list, the operator greps the list to find the attribute. If found, a true value is returned. Otherwise, the return value is false.

Given...

    # where x = ['one', 'two', 'three']
    x contains 'five'  # false
    x contains 'six'   # false
    x contains 'one'   # true

Hashes

If the variable is a hash reference, the operator returns true if the specified element in the hash has ever been initialized, even if the corresponding value is undefined.

Given...

    # where x = { okay => 'okay', blah => undef }
    x contains 'okay'     # false
    x contains 'alright'  # false
    x contains 'blah'     # true

Known Bugs

None right now. Give it time.

Author

Sanko Robinson <sanko@cpan.org> - http://sankorobinson.com/

License and Legal

Copyright (C) 2009-2012 by Sanko Robinson <sanko@cpan.org>

This program is free software; you can redistribute it and/or modify it under the terms of The Artistic License 2.0. See the LICENSE file included with this distribution or http://www.perlfoundation.org/artistic_license_2_0. For clarification, see http://www.perlfoundation.org/artistic_2_0_notes.

When separated from the distribution, all original POD documentation is covered by the Creative Commons Attribution-Share Alike 3.0 License. See http://creativecommons.org/licenses/by-sa/3.0/us/legalcode. For clarification, see http://creativecommons.org/licenses/by-sa/3.0/us/.