[FIXED] Can't install phpDocumentor via Composer

Issue

In composer.json I've got

{
    "require":
    {
        "phpdocumentor/phpdocumentor": "*"
    }
}

It's what is there because I'm trying to install phpDocumentor into an isolated folder with ./composer.phar install command. But what I'm getting is

Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - phpdocumentor/phpdocumentor v2.0.0 requires phpdocumentor/template-abstract ~1.2 -> satisfiable by phpdocumentor/template-abstract[1.2, 1.2.1].
    - phpdocumentor/phpdocumentor v2.0.1 requires phpdocumentor/template-abstract ~1.2 -> satisfiable by phpdocumentor/template-abstract[1.2, 1.2.1].
    - phpdocumentor/phpdocumentor v2.1.0 requires phpdocumentor/template-abstract ~1.2 -> satisfiable by phpdocumentor/template-abstract[1.2, 1.2.1].
    - phpdocumentor/phpdocumentor v2.2.0 requires phpdocumentor/template-abstract ~1.2 -> satisfiable by phpdocumentor/template-abstract[1.2, 1.2.1].
    - phpdocumentor/phpdocumentor v2.3.2 requires phpdocumentor/template-abstract ~1.2 -> satisfiable by phpdocumentor/template-abstract[1.2, 1.2.1].
    - phpdocumentor/phpdocumentor v2.4.0 requires phpdocumentor/template-abstract ~1.2 -> satisfiable by phpdocumentor/template-abstract[1.2, 1.2.1].
    - phpdocumentor/phpdocumentor v2.3.1 requires dompdf/dompdf dev-master@dev -> no matching package found.
    - phpdocumentor/phpdocumentor v2.3.0 requires dompdf/dompdf dev-master@dev -> no matching package found.
    - phpdocumentor/template-abstract 1.2.1 requires ext-xsl * -> the requested PHP extension xsl is missing from your system.
    - phpdocumentor/template-abstract 1.2 requires ext-xsl * -> the requested PHP extension xsl is missing from your system.
    - Installation request for phpdocumentor/phpdocumentor * -> satisfiable by phpdocumentor/phpdocumentor[v2.0.0, v2.0.1, v2.1.0, v2.2.0, v2.3.0, v2.3.1, v2.3.2, v2.4.0].

Potential causes:
 - A typo in the package name
 - The package is not available in a stable-enough version according to your minimum-stability setting
   see <https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion> for more details.

Solution

The error message indicates that you are missing the XSL extension in your PHP setup. You can see http://www.php.net/manual/en/xsl.installation.php for more information on installing that extension.

Please note that the XSL extension is not necessary for the default template; you can also choose to use the PHAR executable or the downloadable archive. These can be downloaded from https://github.com/phpDocumentor/phpDocumentor2/releases/latest. These two do not check for the XSL extension and can thus be safely used.

Answered By - mvriel