Math Shortcode

Here is a shortcode that allows you to build equations using any shortcodes or numbers plus any of  the four operators: + - * /

Format the number with optional attributes: decimal=2 dec_point='.' thousands_sep=',' (those are the defaults)

Example: [math decimal=0 thousands_sep='']0 + 0 - [384] / 100[/math]

Will only work if you separate everything with a single space.

add_shortcode( 'math', function( $a, $content = '' ) {// change 'math' to whatever you want the shortcode to be named

if ( ! $content ) return "(No equation given)";
// Run Shortcodes to get values
$content = do_shortcode( $content );
// Seperate at spaces (after removing commas space at front and end)
$parts = explode( ' ', trim( str_replace( ',', '', $content ) ) );
// Check for odd number of parts (greater than 1)
$count = count( $parts );
if ( $count === 1 || $count % 2 !== 1 ) return "(Malformed equation)";
// Set subtotal as the first number
$total = (float) $parts[0];
// Process additional numbers using the correct operator
for ( $i = 1; $i < $count; ) {
  switch ( $parts[$i++] ) {
    case '+':
      $total += $parts[$i++];
      break;
    case '-':
      $total -= $parts[$i++];
      break;
    case '/':
      if ( $parts[$i] == 0 ) return '0';// if dividing by zero, abort and return 0 to avoid php warnings
      $total /= $parts[$i++];
      break;
    case '*':
    case 'x':
    case 'X':
      $total *= $parts[$i++];
      break;
  }
}
// Handle format, defaults: decimal=2 dec_point='.' thousands_sep=','
$decimal = 2;
$dec_point = '.';
$thousands_sep = ',';
if ( isset( $a['decimal'] ) ) {
  $decimal = (int) $a['decimal'];
}// Seems like formidable allows decimal or round
elseif ( isset( $a['round'] ) ) {
  $decimal = (int) $a['round'];
}
if ( isset( $a['dec_point'] ) ) {
  $dec_point = $a['dec_point'];
}
if ( isset( $a['thousands_sep'] ) ) {
  $thousands_sep = $a['thousands_sep'];
}

return number_format( $total, $decimal, $dec_point, $thousands_sep );
});