有趣的字符串铸造

Question

如何让我下面的字符串转换：

"ln(5*x)" -> "Math.log(5*x)" 

Answer 1

"ln(5*x)".sub('ln','Math.log') #=> "Math.log(5*x)"

Answer 2

"math.log(#{"ln(5*x)"[/ln\((.*)\)/,1]})"