Replace full content with excerpt

replace-content-with-excerpt.php

<?php # -*- coding: utf-8 -*-
/**
 * Plugin Name: Replace full content with excerpt
 * Description: Replaces the full content on post listings with an excerpt
 * Version:     2012.06.22
 * Author:      Fuxia Scholz
 * License:     MIT
 * License URI: http://www.opensource.org/licenses/mit-license.php
 */

add_filter( 'the_content', 't5_replace_content_with_excerpt', 100 );

/**
 * Return excerpt if we are not on a singular post view.
 *
 * @param  string $content
 * @return string
 */
function t5_replace_content_with_excerpt( $content )
{
	if ( is_singular() )
	{
		return $content;
	}
	// remove our filter temporarily.
	// Otherwise we run into a infinite loop in wp_trim_excerpt().
	remove_filter( 'the_content', __FUNCTION__, 100 );
	$excerpt = apply_filters( 'the_excerpt', get_the_excerpt() );
	add_filter( 'the_content', __FUNCTION__, 100 );
	return $excerpt;
}

Is it possibe to revert this to actually do it the other way? I need full posts versus excerpts on the homepage and of course theme customizer does not provide the option - thks (https://wordpress.stackexchange.com/questions/364907/custom-css-for-full-post-vs-excerpt-content-options)

here is what I have to do exactly the contrary, placed in my child theme folder but it does not work

/**
 * Plugin Name: Replace full excerpt with content
 * Description: Replaces the excerpt on post listings with full content
 * Version:     2012.06.22
 * Author:      Fuxia Scholz <info@toscho.de>
 * Author URI:  http://toscho.de
 * License:     MIT
 * License URI: http://www.opensource.org/licenses/mit-license.php
 */

add_filter( 'the_excerpt', 't5_replace_excerpt_with_content', 100 );

/**
 * Return content if we are not on a singular post view.
 *
 * @param  string $excerpt
 * @return string
 */
function t5_replace_excerpt_with_content( $excerpt )
{
	if ( is_singular() )
	{
		return $excerpt;
	}
	// remove our filter temporarily.
	// Otherwise we run into a infinite loop in wp_trim_excerpt().
	remove_filter( 'the_excerpt', __FUNCTION__, 100 );
	$content = apply_filters( 'the_content', get_the_content() );
	add_filter( 'the_excerpt', __FUNCTION__, 100 );
	return $content;
}