Taco Module for Perl

Introduction

Taco is a system for bridging between scripting languages. Its goal is to allow you to call routines written for one language from another. It does this by running the second language interpreter in a sub-process, and passing messages about actions to be performed inside that interpreter.

In principle, to interface scripting languages it might be preferable to embed the interpreter for one as an extension of the other. However this might not be convenient or possible, and would need to be repeated for each combination of languages. Instead Taco only requires a "client" module and "server" script for each language, which should be straightforward to install, and its messages are designed to be generic so that they can be used between any combination of languages.

For more information about Taco, please see the Taco Homepage.

Examples

Here are a few examples of the types of things which can be done with Taco:

Calling a Function

In this example, the Python numpy.median function is used to calculate the median of an array of numbers. The answer is returned to the Perl script.

    use Alien::Taco;
    my $taco = new Alien::Taco(lang => 'python');
    $taco->import_module('numpy');

    my @array = (1, 2, 4, 8);

    print $taco->call_function('numpy.median', args => [\@array]);

Output: 3

Instantiating a Alien::Taco object starts a sub-process running a "server" script, in this case in Python. This script then handles the instructions to import a module and call a function.

Working with Objects

References to objects are returned as instances of the Alien::Taco::Object class:

    $taco->import_module('datetime', args => ['datetime']);
    my $dt = $taco->construct_object('datetime', args => [2014, 4, 1]);
    print $dt;

Output: Alien::Taco::Object=HASH(0x.......)

The actual object is cached by the server script, and the reference can be used to interact with it.

    print $dt->call_method('isoweekday');

Output: 2

Handling Exceptions

Exceptions which occur while the server is processing an instruction are caught and re-raised by the Perl module.

    $dt->call_method('replace', kwargs => {month => 13});

Exits with: received exception: exception caught: month must be in 1..12

Installation

This module can be installed, including basic unit tests, as follows:

    perl Build.PL
    ./Build
    ./Build test
    ./Build install

Integration Tests

This package also includes integration tests which test the complete Taco system. These tests can be found in the ti-* directories.

Perl

The test using a Perl "server" can be run directly from this package:

    ./Build tiperl

Other Languages

The following tests require a Taco "server" script for the corresponding language to already be installed in the search path:

Python

    ./Build tipython

Java

    ./Build tijava

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.

Additional Links

Repository at GitHub

Taco Homepage