Question

I have a function which accepts an input from the user. The input maybe an integer, a float or a string. I have three overloaded functions which should be called based on the DATA TYPE of the entered data. For example, if the user enters an integer (say 100), the function having integer parameter should be called. If the user enters a string (say “100”) the function having the string parameter should be called.

So I need to find out the data type of the entered data. With regular expressions I am able to distinguish between an integer and a float (since I just need to find out the type, I wont prefer using the library provided at cpan.org), but I am not able to figure out how to differentiate an integer from a string. Perl treats “100” and 100 as the same? Is there any way to work around this problem?

Answer 1

From perldoc perldata:

Scalars aren’t necessarily one thing or another. There’s no place to declare a scalar variable to be of type “string”, type “number”, type “reference”, or anything else. Because of the automatic conversion of scalars, operations that return scalars don’t need to care (and in fact, cannot care) whether their caller is looking for a string, a number, or a reference. Perl is a contextually polymorphic language whose scalars can be strings, numbers, or references (which includes objects). Although strings and numbers are considered pretty much the same thing for nearly all purposes, references are strongly-typed, uncastable pointers with builtin reference-counting and destructor invocation.

So for integer scalars, you’ll just need to decide ahead of time how you want to process them. Perl will cheerfully convert from a number to a string or vice versa depending on the context.