gulpfile.js

var gulp = require('gulp'),
    pot = require( 'gulp-wp-pot' ),
    fs = require('fs'),
    git = require('gulp-git');

var addons = [ 'pms-add-on-bbpress', 'pms-add-on-content-dripping', 'pms-add-on-discount-codes', 'pms-add-on-email-reminders',
    'pms-add-on-global-content-restriction', 'pms-add-on-invoices', 'pms-add-on-member-subscription-fixed-period', 'pms-add-on-multiple-subscriptions-per-user'
    , 'pms-add-on-navigation-menu-filtering', 'pms-add-on-paypal-express-pro', 'pms-add-on-paypal-standard-recurring-payments', 'pms-add-on-recaptcha'
    , 'pms-add-on-stripe', 'pms-add-on-pay-what-you-want', 'pms-add-on-group-memberships', 'pms-add-on-tax' ];


/* create a pot file from the main plugin and all the addons */
gulp.task( 'pot', function () {

    //make sure we are in the original working directory
    process.chdir('./../paid-member-subscriptions');

    //create all the paths in witch we look for gettext
    lookIn = [ 'extend/**/*.php','includes/**/*.php', '*.php' ];
    addons.forEach(function(addon){
        lookIn.push( './../'+ addon +'/**/*.php' );
    });

    return gulp.src( lookIn )
        .pipe( pot({
            domain: 'paid-member-subscriptions',
            package: 'Paid Member Subscriptions'
        }) )
        .pipe( gulp.dest( 'translations/paid-member-subscriptions.pot' ) );
});

//create a php catalog that contain all the strings in the pot. this will reside in the translation folder and is used for translate.wordpress.org when they scan for the strings and the string is not in the free version
gulp.task('catalog', function(cb) {

    var fileContent = fs.readFileSync("translations/paid-member-subscriptions.pot", "utf8");
    returnFile = '';
    regex = new RegExp( /msgid ([^]*?)msgstr/g ); //grab everything between msgid and msgstr
    match = regex.exec(fileContent.toString());
    while (match != null) {
        if( typeof match[1] != 'undefined' ) {
            match[1] = match[1].replace( /(?:\r\n|\r|\n)/g, '' ); //remove the new lines inserted by pot
            match[1] = match[1].replace( /(?<!\\|^)""/g, '' ); //recombine in a single string by removing the ""

            // Check if row contains named printf placeholders
            var matches = match[1].match(/%(\d)\$/g)

            if( matches != null ){

                // string is "This is my string"
                // this removes the double quotes around it so we can add single quotes later
                // double quotes are changing the meaning of strings that contain sprintf variables (%1$s)
                match[1] = match[1].replace( /["]+/g, "" )

                // escape ' that are inside the string
                match[1] = match[1].replace( /[']+/g, "\\'" )

                returnFile += "<?php __('" + match[1] + "', 'paid-member-subscriptions' ); ?>\n"

            } else
                returnFile += '<?php __(' + match[1] + ', "paid-member-subscriptions"); ?>\n'


        }
        match = regex.exec(fileContent.toString());
    }

    returnFile = returnFile.replace( /msgid_plural /g, ', "paid-member-subscriptions"); ?>\n<?php __(' );

    fs.writeFile( 'translations/paid-member-subscriptions.catalog.php', returnFile, cb );

});