207 			$stack = $this->nfx( $matches[3] );
208 			if ( false === $stack ) {
212 			$stack_count = count( $stack );
214 				$token = $stack[ $i ];
217 						$stack[ $i ] = $this->variables[ $token ];
223 			$this->functions[ $function_name ] = array( 'args' => $args, 'func' => $stack );
272 		$stack = new EvalMath_Stack();
298 				$stack->push( '_' );
314 …while ( $stack->count > 0 && ( $o2 = $stack->last() ) && in_array( $o2, $ops, true ) && ( $ops_r[ …
316 					$output[] = $stack->pop();
319 				$stack->push( $op ); // Finally put OUR operator onto the stack.
327 				while ( '(' !== ( $o2 = $stack->pop() ) ) {
336 …if ( 1 === preg_match( '/^(' . self::$name_pattern . ')\($/', (string) $stack->last( 2 ), $matches…
340 					$arg_count = $stack->pop();
341 					$stack->pop(); // $fn
376 				while ( '(' !== ( $o2 = $stack->pop() ) ) {
386 …if ( 0 === preg_match( '/^(' . self::$name_pattern . ')\($/', (string) $stack->last( 2 ), $matches…
390 				$stack->push( $stack->pop() + 1 );
392 				$stack->push( '(' );
397 				$stack->push( '(' ); // That was easy.
408 						$stack->push( $value );
409 						$stack->push( 1 );
410 						$stack->push( '(' );
425 				if ( '(' !== $stack->last() || 1 !== $stack->last( 2 ) ) {
429 …if ( 1 === preg_match( '/^(' . self::$name_pattern . ')\($/', (string) $stack->last( 3 ), $matches…
430 					$stack->pop(); // (
431 					$stack->pop(); // 1
432 					$stack->pop(); // $fn
480 		while ( ! is_null( $op = $stack->pop() ) ) {
505 		$stack = new EvalMath_Stack();
515 					$op1 = $stack->pop();
534 						$arg = $stack->pop();
559 					$stack->push( $result );
566 						$arg = $stack->pop();
574 					$stack->push( $this->pfx( $this->functions[ $function_name ]['func'], $args ) );
579 				$op2 = $stack->pop();
583 				$op1 = $stack->pop();
589 						$stack->push( $op1 + $op2 );
592 						$stack->push( $op1 - $op2 );
595 						$stack->push( $op1 * $op2 );
601 						$stack->push( $op1 / $op2 );
604 						$stack->push( pow( $op1, $op2 ) );
607 						$stack->push( (int) ( $op1 > $op2 ) );
610 						$stack->push( (int) ( $op1 < $op2 ) );
614 …$stack->push( (int) ( $op1 == $op2 ) ); // Don't use === as the variable type can differ (int/doub…
620 				$stack->push( -1 * $stack->pop() );
625 					$stack->push( $token );
627 					$stack->push( $this->variables[ $token ] );
629 					$stack->push( $variables[ $token ] );
636 		if ( 1 !== $stack->count ) {
639 		return $stack->pop();
739 	protected $stack = array();  variable in EvalMath_Stack
757 		$this->stack[ $this->count ] = $value;
771 			return $this->stack[ $this->count ];
786 			return $this->stack[ $this->count - $n ];