This function returns a boolean result on passing in an open, high, low and close price as well as the direction (true = bullish; false = bearish).

isPinBar.mq4

/** v6.0
 * A pin bar is a hammer like formation where the body of the candle
 * is at one extreme of the entire candle and the wick making up the
 * remainder of the candle. The body of the candle should be no more
 * than 1/3 of the entire candle, with the remaining wick taking up
 * no more than 2/3 of the remainder of the body.
 */
bool isPin( double o, double h, double l, double c, bool isLong ) {	
	double hx, lx, rng = h - l, pct = 1/3;
	if ( isLong ) { 
		hx = h - MathMin( o, c ); // body
		lx = MathMax( o, c ) - l; // wick
	} else {
		hx = h - MathMax( o, c ); // wick
		lx = MathMin( o, c ) - l; // body
	}
	if ( isLong && hx/rng <= pct && lx/rng >= 1 - pct ) return( true );
	if ( !isLong && hx/rng >= 1 - pct && lx/rng <= pct ) return ( true );
	return( false );
}