Python - Encapuslate python objects

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SEE ALSO

NAME

Python - Encapuslate python objects

SYNOPSIS

    use Python qw(getattr list);

    # constructors
    $list = list(1..10);

    # accessor
    if (my $foo = getattr($o, "foo")) {
        # ...
    }

DESCRIPTION

Python is an interpreted, interactive, object-oriented programming language programming language created by Guido van Rossum (www.python.org). This manpage describe the perl interface to python data managed by an embedded Python interpreter.

The Python:: namespace contain various functions to construct, modify and examine python objects. Python objects themselves are wrapped up in instances of the perl class Python::Object.

Constructors

The following object constructor functions are provided. They all return Python::Object instances. Usually one will not have to construct Python::Objects directly since they are constructed implicitly when python data is passed to perl either as perl function arguments or as the return values from calls into python.

$o = object($something);

The object() constructor will first make a python object of whatever perl data is passed in and then return a Python::Object wrapper for it. A call like:

  $o = object("$something")

will make sure you produce a string object.

$o = int( INT )

This will make a new integer object.

$o = long( STRING_OF_DIGITS )

This will make a new long integer object. Long integers can grow to arbitrary size (bignum).

$o = float( NUMBER )

This will make a new float object.

$o = complex( NUMBER, NUMBER )

This will make a new complex object with the given real and imag parts.

$o = list( ELEM,... )

This will make a new list object initialized with the elements passed in as separate arguments to the constructor function.

$o = tuple( ELEM,... )

This will make a new tuple object initialized with the elements passed in as separate arguments to the constructor function.

$o = dict( KEY => VALUE,... );

This will make a new dictionary object. Initial items are extracted as pairs from the argument list.

Python functions

The following functions with mostly identical behaviour to the corresponding python builtins are available. These functions will croak if the $o argument is not a Python::Object instance.

getattr($o, $name)

hasattr($o, $name)

setattr($o, $name => $value)

delattr($o, $name)

These functions provide access to the attributes of an object.

cmp($o1, $o2)

Compares the two objects and returns -1, 0 or 1 if $o is less, equal or greater than $o2 respectively.

id($o)

Returns a number which will be different for different objects.

hash($o)

This return the hash value of the object.

len($o)

This return the length of the object.

type($o)

Returns the corresponsding type object.

str($o)

Returns a stringified representation of the object.

Overloaded as perl stringify operator.

repr($o)

Returns a possibly different stringified representation of the object that tries be valid python syntax.

exec($string, [$globals, [$locals]);

Executes a bit of python code. The global and local namespace to use during execution can be passed in as dictionary objects. If omitted they default to the __main__ namespace.

eval($string, [$globals, [$locals]);

Returns the value of the expression given as first argument. The global and local namespace can be overridden like for exec.

apply($o, \@args, \%keywords)

This will invoke the object with the given arguments. The \@args argument can be a perl array reference, undef or some python sequence. The \%keywords argument can be a perl hash reference, undef or a python directory.

funcall($o, @args)

This will invoke the object with the given arguments if it is callable. Similar to apply(), but arguments are not passed as a single list reference argument.

Import( $module )

Loads the module and returns a reference to it. Notice that this function is spelled with a capital ``i''. (The reason is that perl already use ``import'' for something else.)

raise($type, $value)

Raise a python exception of the specific type. References to Python's standard exception types can be obtained from the Python::Err namespace. E.g.:

  Python::raise(Python::Err::TypeError, "'foo' wanted here");

Python API functions

The following functions that map the Python internal C API are made available.

PyObject_GetItem($o, $key)

PyObject_SetItem($o, $key, $value)

PyObject_DelItem($o, $key)

These methods provide access to the items of objects that implement the sequence or the mapping interface. These function also have aliases named getitem(), setitem() and delitem() after the pattern established by the corresponding {get,set,del}attr() calls.

PyObject_IsTrue($o)

This return a boolean value for the object.

Overloaded as boolean test operator.

Type check functions

The following functions determine if the object is of the given type. If $o is not a reference to a Python::Object instance, then these all return FALSE.

PyCallable_Check($o): Return TRUE if the object is callable.
PyNumber_Check($o);: Return TRUE if the object provide the number interface.
PySequence_Check($o): Return TRUE if the object provide the sequence interface.
PyMapping_Check($o): Return TRUE if the object provide the mapping interface.

COPYRIGHT

This code is distributed under the same terms as Perl; you can redistribute it and/or modify it under the terms of either the GNU General Public License or the Artistic License.

THIS SOFTWARE IS PROVIDED BY ACTIVESTATE `AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ACTIVESTATE OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.