gppa-lmt-range-modifier.php

<?php
/**
 * Gravity Perks // Populate Anything // Range Modifier for Live Merge Tags
 * https://gravitywiz.com/documentation/gravity-forms-populate-anything/
 *
 * Use the :range modifier with checkbox merge tags to get the range of checked options
 * Works well with the :value modifier
 * 
 * Will return `x - y` where the min and max are different, or `x` if they are the same
 *
 * # Return the range of checked values in field 4
 * @{Checkboxes:4:value,range}
 * 
 */
add_filter( 'gppa_live_merge_tag_value', function( $value, $merge_tag ) {
	
	$bits      = explode( ':', $merge_tag );
	$modifiers = gw_parse_modifiers( array_pop( $bits ) );
	
	if ( ! isset( $modifiers['range'] ) ) {
		return $value;
	}

	$bits = explode( ',', $value );
	$min = trim( min( $bits ) );
	$max = trim( max( $bits ) );
	
	if( $min == $max ){
		return $min;
	}
	
	return $min . ' - ' . $max;
		
}, 10, 2 );

if ( ! function_exists( 'gw_parse_modifiers' ) ) {
	function gw_parse_modifiers( $modifiers_str ) {

		preg_match_all( '/([a-z]+)(?:(?:\[(.+?)\])|,?)/i', $modifiers_str, $modifiers, PREG_SET_ORDER );
		$parsed = array();

		foreach ( $modifiers as $modifier ) {

			list( $match, $modifier, $value ) = array_pad( $modifier, 3, null );
			if ( $value === null ) {
				$value = $modifier;
			}

			// Split '1,2,3' into array( 1, 2, 3 ).
			if ( strpos( $value, ',' ) !== false ) {
				$value = array_map( 'trim', explode( ',', $value ) );
			}

			$parsed[ strtolower( $modifier ) ] = $value;

		}

		return $parsed;
	}
}