Programming languages use expressions to manipulate application data. Expressions resemble algebraic formulas in that they often specify mathematical transformations involving the program's variables. For example, the expression
a+10 tells the program to evaluate the expression
10 added to
a. This does not change the value of
a; rather, the computer simply computes this sum and then performs some action based on that sum.
JSTL supports expressions through the use of two expression languages. JSTL includes support for scriptlet-based expressions, called rtexprvalue expressions. JSTL also introduces Expression Language (EL), which greatly simplifies expression handling in JSTL. The designers of JSTL assume ...