EL syntax

In this section, you can see an overview of the main aspects of EL 2.2 and 3.0 syntax. EL supports a handful of operators and reserved words. Each of these are quickly described in the following section (more details are in the EL specification document (http://download.oracle.com/otndocs/jcp/el-3_0-fr-eval-spec/index.html)).

EL operators

EL supports the following categories of operators—arithmetic, relational, logical, conditional, empty and added starting with EL 3.0, string concatenation, assignment and semicolon operators:

Textuals	Description	Symbols
A + B	Addition	+
A - B	Subtraction	-
A * B	Multiplication	*
A {div, /} B	Arithmetic operator division	/, div
A {mod, %} B	Arithmetic operator modulo	%, mod
A {and, &&} B	Logical AND	&&, and
A {or, ||} B	Logical OR	||, or
{not, !} A	Logical opposite	!, not
A {lt, <} B	Relational less than	<, lt
A {gt, >} B	Relational greater than	>, gt
A {le, <=} B	Relational less than or equal to	<=, le
A {ge, >=} B	Relational greater than or equal to	>=, ge
A {eq, ==} B	Equal to	==, eq
A {ne, !=} B	Not equal to	!=, ne
A = B	Assignment (EL 3.0)	=
A ; B	Semicolon (EL 3.0)	;
A += B	String concatenation (EL 3.0)	+=
A -> B	Lambda expression (EL 3.0)	->
empty A	Determine whether a value is null or empty
A ? B : C	Evaluates B or C, depending on the result of the evaluation of A. Known as the ternary operator.	?:
	Used when writing EL expressions	.
	Used when writing EL expressions	[]

EL precedence of operators

Conforming to EL specification, the precedence of operators from the highest to lowest, left to right is as follows:

• [].
• () (used to change the precedence of operators)
• - (unary) not ! empty
• * / div % mod
• + - (binary)
• +=
• < > <= >= lt gt le ge
• == != eq ne
• && and
• || or
• ? :
• -> (lambda expression)
• =
• ;

EL reserved words

EL defines the following reserved words:

• and, or, not, eq, ne, lt, gt, le, ge, true (Boolean literal), false (Boolean literal), null, instanceof (a Java keyword to do a class comparison between objects), empty, div, and mod