Wall Street gains as weak dollar boosts commodities

Wall Street gains were driven by materials stocks on Monday as a weaker dollar boosted commodities, and investors turned their focus to the earnings season. Profits at S&P 500 companies are expected to have fallen 7.7 percent on average in the first quarter, according to Thomson Reuters I/B/E/S, under pressure from a weak global economy. Alcoa, seen as the unofficial start to quarterly earnings season, is set to post first-quarter results after the market closes.