Operators

Mathematical operators

Operator	Name	Description
+	Add	Add numbers, e.g. `2 + 2` is 4
-	subtract	Subtract numbers, e.g. `2 - 2` is 0
*	multiply	Multiply numbers, e.g. `2 * 3` is 6
/	divide	Return the quotient of a number, e.g. `6 / 2` is 3
^	exponentiate	Raises one number to the power of another, e.g. `2 ^ 2` is 4
%	modulus	Returns the remainder of a number, e.g. `5 % 2` is 1
MOD	modulus	Returns the remainder of a number, e.g. `5 mod 2` is 1
\	integer divide	Divides giving an integer result, e.g. `7 \ 2` is 3
++	increment	Increments a number. Can be used before or after an assignment, e.g. `a = b++` would assign the value of b to a, then increment b. `a = ++b` would increment b, then assign the new value to a. In both cases, b would be incremented. (not thread safe, see below)
--	decrement	Decrements a number. Can be used before or after an assignment, e.g. `a = b--` would assign the value of b to a, then decrement b. `a = --b` would decrement b, then assign the new value to a. In both cases, b would be decremented. (not thread safe, see below)
+=	Compound add	A shorthand operator for adding to a value, e.g. `a += b` is equivalent to writing `a = a + b`
-=	Compound subtract	A shorthand operator for subtracting from a value, e.g. `a -= b` is equivalent to writing `a = a - b`
*=	Compound multiply	A shorthand operator for multiplying a value, e.g. `a = b` is equivalent to writing `a = a * b`
/=	Compound divide	A shorthand operator for dividing a value, e.g. `a /= b` is equivalent to writing `a = a / b`

Demonstration of unsafe threaded behavior with ++ and -- operators

   echo(server.lucee.version & "<br>");
    s = getTickCount();
    cycles = 2000;
	threads = 4;
	echo("cycles: " & cycles &" <br>");
	function test(){
        var array = [];
		for ( var x = 1; x lte cycles; x++ ) {
			array.append( x );
		}

		var ops = {
		    plusPlus: 0,
		    minusMinus: 0
		};
		array.each( ( el ) => {
			ops.plusPlus++;
			ops.minusMinus--;
		}, true, threads );

		dump( var=ops, label="values should always be 2000 or -2000, but these operators aren't thread safe");
	}

	function testSafe(){
        var array = [];
		for ( var x = 1; x lte cycles; x++ ) {
			array.append( x );
		}

		var ops = {
		    plusPlus: 0,
		    minusMinus: 0
		};
		array.each( ( el ) => {
		    lock name="loop" type="exclusive" {
		        ops.plusPlus++;
			    ops.minusMinus--;
			}
		}, true, threads );

		dump( var=ops, label="values will always be 2000 or -2000, due to locking");
	}

	cftimer(type="inline", label="not thread safe"){
        test();
    }
    cftimer(type="inline", label="thread safe"){
        testSafe();
    }
	//}
	echo ("<br>" & (getTickCount()-s) & "ms");

Logical operators

operators	Name	Description
!	logical inversion	! true is false
NOT	logical inversion	not true is false
AND	logical and	Returns true if both operands are true, e.g. `1 eq 1 and 2 eq 2` is true
&&	logical and	Returns true if both operands are true, e.g. `1 eq 1 && 2 eq 2` is true
OR	logical or	Returns true if either or both operands are true, e.g. `1 eq 1 or 2 eq 3` is true
\|\|	logical or	Returns true if either or both operand are true, e.g. `1 == 1 \|\| 2 == 3` is true
XOR	logical exclusive or	Returns true if either operand is true, but not both, e.g. `1 == 1 XOR 2 == 3` is true, but `1 == 1 XOR 2 == 2` is false

Comparison operators

operators	Name	Description
EQ	equals	Returns true if operands are equal, e.g. `"A" EQ "A"` is true
==	equals	Returns true if operands are equal, e.g. `"A" == "A"` is true
===	identical	Returns true if operands are the same object in memory, false if they are not, (Note this is different than how JavaScript's `===` operator works). Lucee 6 === works like javascript, comparing type and value
NEQ	does not equal	Returns true if operands are not equal, e.g. `"A" NEQ "B"` is true
<>	does not equal	Returns true if operands are not equal, e.g. `"A" <> "B"` is true
!=	does not equal	Returns true if operands are not equal, e.g. `"A" != "B"` is true
!==	is not identical	Returns true if operands are not equal or not of the same type, e.g. `1 !== "1"` is true, but `1 !== 1` is false
GT	greater than	Returns true if the operand on the left is has a higher value than the operand on the right, e.g. `1 GT 2` is false
>	greater than	Returns true if the operand on the left is has a higher value than the operand on the right, e.g. `1 > 2` is false
LT	less than	Returns true if the operand on the left has a lower value than the operand on the right, e.g. `1 LT 2` is true
<	less than	Returns true if the operand on the left has a lower value than the operand on the right, e.g. `1 < 2` is true
GTE	greater than or equal to	Returns true if the operand on the left has a value higher than or equal to the operand on the right, e.g. `2 GTE 2` is true
>=	greater than or equal to	Returns true if the operand on the left has a value higher than or equal to the operand on the right, e.g. `2 >= 2` is true
LTE	less than or equal to	Returns true if the operand on the left has a value lower than or equal to the operand on the right, e.g. `2 LTE 2` is true
<=	less than or equal to	Returns true if the operand on the left has a value lower than or equal to the operand on the right, e.g. `2 <= 2` is true
CONTAINS	contains	Returns true if the left operand contains the right operand, e.g. `"SMILES" CONTAINS "MILE"` is true
CT	contains	Returns true if the left operand contains the right operand, e.g. `"SMILES" CT "MILE"` is true
DOES NOT CONTAIN	does not contain	Returns true if the left operand does not contain the right operand, e.g. `"SMILES" DOES NOT CONTAIN "RHUBARB"` is true
NCT	does not contain	Returns true if the left operand does not contain the right operand, e.g. `"SMILES" NCT "RHUBARB"` is true

String operators

operators	Name	Description
&	concatenation	Joins two strings, e.g. `The result of "Hello" & "World"` is "HelloWorld"
&=	compound concatenation	A shorthand operator that joins two strings, e.g. `a &= b` would be equivalent to writing `a = a & b`

Ternary operator

The ternary operator lets you return results conditionally, in a very compact amount of code:

condition ? value1 : value2

This would return value1 if condition is true, otherwise it would return false. It's comparable to the following logical structure:

<cfif condition>
    #value1#
<cfelse>
    #value2#
</cfif>

or the function:

iif(condition, "value1", "value2")

For example:

animal = "cat";
writeOutput(animal == "cat"? "Meow" : "Woof");

would output "Meow".

Elvis operator

The "Elvis operator" in Lucee works like a Null Coalescing operator in other languages. If the expression to the left of the operator refers to a variable that does not exist, or is null, then the expression on the right is then evaluated and is the result of the full expression. If the expression to the left of the operator refers to a variable that does exist, the right hand expression is never evaluated.

Some examples:

// the variable 'rockstar' does not exist, so
// "Elvis Presley" is the result of the expression
dump( var=rockstar ?: "Elvis Presley", label="rockstar ?: ""Elvis Presley""" );

// another example of variable does
// not exist - this time showing
// that the right hand side is evaluatd
i=1;
dump( var=( n ?: ++i ), label="n ?: ++i" );
dump( var=i, label="i (expect to be changed from 1 to 2)" );

// an example of the variable DOES
// exist - proving that the right
// hand side is NOT evaluatd
i=1;
n=2;
dump( var=( n ?: ++i ), label="n ?: ++i" );
dump( var=i, label="i (expect to be 1, still unchanged)" );

// the variable is declared but is null
// right hand is chosen
rockstar=NullValue();
dump( var=( rockstar ?: "Joni Mitchell" ), label="rockstar ?: ""Joni Mitchell""" );

// it can be used with complex variables
complexVar = [ { test=[ { test=2 } ] } ];
dump( var=( complexVar[ 2 ].test[ 1 ].test ?: "Default" ), label="complexVar[ 2 ].test[ 1 ].test ?: ""Default""" )
dump( var=( complexVar[ 1 ].test[ 1 ].test ?: "Default" ), label="complexVar[ 1 ].test[ 1 ].test ?: ""Default""" )

// Finally, this is not a shorthand of the
// ternary operator. The variable EXISTS
// its boolean value is not relevant to elvis
someVar=false;
dump( var=( someVar ?: true ), label="someVar ?: true" );

Safe Navigation Operator

The Safe Navigation Operator ?. is used to reference nested properties which may not exist, safely returning a null value when a property doesn't exist.

This makes code safer and more concise by handling null or undefined values gracefully during both property and method access.

var property = context?.object?.property;

It can be also combined with the Elvis Operator, to write much cleaner and more robust code when dealing with complex, varied objects.

var prop = some?.key?.that?.is?.not?.there ?: "I'm a default value!";

You can also use safe navigation on method calls:

foo = "foo"

writedump( foo.toUpperCase() )                     // FOO
writedump( foo?.toCrazyCase() ?: "just kidding" )   // just kidding

The .toCrazyCase() method doesn't exist, so null is returned since safe navigation was used.

In Javascript, this is called optional chaining

Naturally, there's a Ben Nadel blog post about this! Using The Safe-Navigation Operator To Safely Clean Up Resources In Lucee 5.3.2.77

Operators not available in tags

You can use <> > < >= and <= in tags, as long as they don't interfere with the tag syntax. In that case you must use the equivalent GT, LT, etc. operators instead.

Casting

Note that in Lucee values are cast to an appropriate type automatically, except when using the identical operators === and !==