
Math::Expression::Evaluator::Util - Common functions for Math::Expression::Evaluator

use Math::Expression::Evaluator::Util qw(is_lvalue);
# ...
if (is_lvalue($ast)){
# $ast represents an lvalue, at the moment just a variable
}

This is package with common functions used in the different modules in the Math::Expression::Evaluator distribution.
is_lvalue($ast) checks if (a simplified version of) $ast represents something that can be assigned to, i.e. is a variable.