Possibility to get the line numbers?

[Анастасія Баша]

 Is there a way to get the current line number (or generally the number of 
element currently being processed) inside a mapper?
The example is a matrix you read line-line by line from the file and need both 
the row and the column numbers. Column number is easy to get, but how to know 
the row number?
 
Thanks a lot in advance, 
Anastasiia