Theme Development

Setup

Clone or download this repo into your theme folder. Ie: wp-content/themes/your-theme
Configure style.css with the appropriate names.
Install and activate the plugin dependencies listed below.
Activate your theme.

Inside your theme open /app/assets/css-assets.php
Add a load_css() call. The first parameter is the URL to the CSS file. The second optional parameter is an array of arguments. See arguments.
If handle is not defined as an arg the URL parameter will be used.
If ver is not defined as an arg the theme version will be used.

Inside your theme open /app/assets/js-assets.php
Add a load_js() call. The first parameter is the URL to the JS file. The second optional parameter is an array of arguments. See arguments.
If handle is not defined as an arg the URL parameter will be used.
If ver is not defined as an arg the theme version will be used.

Extended CPTs is integrated
Register new post types and taxonomies by opening inside your theme /app/content-types/content-types.php
Follow documentation for Extended CPTs here.

Advanced Custom Fields is used to created custom fields.
It's recommended to register fields via PHP.
For each template, post type or options page you should create a new PHP file in the directory inside your theme /app/custom-fields. In terms of naming convention it should match the template or post type name. Examples: /app/custom-fields/front-page.acf.php or /app/custom-fields/articles.acf.php
An options page is setup by default in functions.php.
A wrapper is available for the ACF PHP API to streamline development. See /app/custom-fields/examples.acf.php.
Using core_field the label will be used as the field name unless the name key is present in the args array.

By default the header, footer and homepage (front-page.php) are set up for you.
Every template, post type, etc. should be set up with a PHP file and a Twig file. For example if you have template-about.php you would have views/template-about.twig
The PHP file should have a class that extends the Core_Template class. Example: class Template_About extends Core_Template. Whatever the class name is will be what it tries to load from the views directory. In this example it'd look for template-about.twig. You can overwrite this by defining a template_file method in your class. See header.php for an example.
Any methods defined in your class will be returned to the Twig template as data. For instance if you have a method hero that returns an array you could access it in your Twig file like {{hero.heading}} if you have a key in your array called heading. I recommend having a method for each section of the template returning relevant data for that section.
The Core_Template class also supplies your Twig template with some commonly accessed data: {{constants.blogURL}}, {{constants.templateURL}}, {{constants.templateDir}}, {{constants.mediaURL}}

_log( $array ); - a wrapper for error_log() that will print strings, arrays or objects to the system error log.
core_get_fields( $key='', $fields=array() ) can help you get your custom fields. See front-page.php for an example.