« Operators: Numeric Operators: Reference »

› ›

Operators: Boolean

IMPORTANT: This documentation is no longer updated. Refer to Elastic's version policy and the latest documentation.

Operators: Boolean

Boolean Not

Use the boolean not operator '!' to NOT a boolean type value where true is flipped to false and false is flipped to true.

Errors

If a value other than a boolean type value or a value that is castable to a boolean type value is given.

Truth

original	result
true	false
false	true

Grammar

boolean_not: '!' expression;

Examples

Boolean not with the boolean type.

boolean x = !false; 
boolean y = !x;

	declare `boolean x`; boolean not `boolean false` → `boolean true`; store `boolean true` to `x`
	declare `boolean y`; load from `x` → `boolean true`; boolean not `boolean true` → `boolean false`; store `boolean false` to `y`

Boolean not with the def type.

def y = true; 
def z = !y;

	declare `def y`; implicit cast `boolean true` to `def` → `def`; store `true` to `y`
	declare `def z`; load from `y` → `def`; implicit cast `def` to `boolean true` → boolean `true`; boolean not `boolean true` → `boolean false`; implicit cast `boolean false` to `def` → `def`; store `def` to `z`

Greater Than

edit

Use the greater than operator '>' to COMPARE two numeric type values where a resultant boolean type value is true if the left-hand side value is greater than to the right-hand side value and false otherwise.

Errors

If either the evaluated left-hand side or the evaluated right-hand side is a non-numeric value.

Grammar

greater_than: expression '>' expression;

Promotion

	byte	short	char	int	long	float	double	def
byte	int	int	int	int	long	float	double	def
short	int	int	int	int	long	float	double	def
char	int	int	int	int	long	float	double	def
int	int	int	int	int	long	float	double	def
long	long	long	long	long	long	float	double	def
float	float	float	float	float	float	float	double	def
double	double	double	double	double	double	double	double	def
def	def	def	def	def	def	def	def	def

Examples

Greater than with different numeric types.

boolean x = 5 > 4; 
double y = 6.0;    
x = 6 > y;

	declare `boolean x`; greater than `int 5` and `int 4` → `boolean true`; store `boolean true` to `x`;
	declare `double y`; store `double 6.0` to `y`;
	load from `y` → `double 6.0 @0`; promote `int 6` and `double 6.0`: result `double`; implicit cast `int 6` to `double 6.0 @1` → `double 6.0 @1`; greater than `double 6.0 @1` and `double 6.0 @0` → `boolean false`; store `boolean false` to `x`

Greater than with def type.

int x = 5;       
def y = 7.0;     
def z = y > 6.5; 
def a = x > y;

	declare `int x`; store `int 5` to `x`
	declare `def y`; implicit cast `double 7.0` to `def` → `def`; store `def` to `y`
	declare `def z`; load from `y` → `def`; implicit cast `def` to `double 7.0` → `double 7.0`; greater than `double 7.0` and `double 6.5` → `boolean true`; implicit cast `boolean true` to `def` → `def`; store `def` to `z`
	declare `def a`; load from `y` → `def`; implicit cast `def` to `double 7.0` → `double 7.0`; load from `x` → `int 5`; promote `int 5` and `double 7.0`: result `double`; implicit cast `int 5` to `double 5.0` → `double 5.0`; greater than `double 5.0` and `double 7.0` → `boolean false`; implicit cast `boolean false` to `def` → `def`; store `def` to `z`

Greater Than Or Equal

edit

Use the greater than or equal operator '>=' to COMPARE two numeric type values where a resultant boolean type value is true if the left-hand side value is greater than or equal to the right-hand side value and false otherwise.

Errors

If either the evaluated left-hand side or the evaluated right-hand side is a non-numeric value.

Grammar

greater_than_or_equal: expression '>=' expression;

Promotion

	byte	short	char	int	long	float	double	def
byte	int	int	int	int	long	float	double	def
short	int	int	int	int	long	float	double	def
char	int	int	int	int	long	float	double	def
int	int	int	int	int	long	float	double	def
long	long	long	long	long	long	float	double	def
float	float	float	float	float	float	float	double	def
double	double	double	double	double	double	double	double	def
def	def	def	def	def	def	def	def	def

Examples

Greater than or equal with different numeric types.

boolean x = 5 >= 4; 
double y = 6.0;     
x = 6 >= y;

	declare `boolean x`; greater than or equal `int 5` and `int 4` → `boolean true`; store `boolean true` to `x`
	declare `double y`; store `double 6.0` to `y`
	load from `y` → `double 6.0 @0`; promote `int 6` and `double 6.0`: result `double`; implicit cast `int 6` to `double 6.0 @1` → `double 6.0 @1`; greater than or equal `double 6.0 @1` and `double 6.0 @0` → `boolean true`; store `boolean true` to `x`

Greater than or equal with the def type.

int x = 5;        
def y = 7.0;      
def z = y >= 7.0; 
def a = x >= y;

	declare `int x`; store `int 5` to `x`;
	declare `def y` implicit cast `double 7.0` to `def` → `def`; store `def` to `y`
	declare `def z`; load from `y` → `def`; implicit cast `def` to `double 7.0 @0` → `double 7.0 @0`; greater than or equal `double 7.0 @0` and `double 7.0 @1` → `boolean true`; implicit cast `boolean true` to `def` → `def`; store `def` to `z`
	declare `def a`; load from `y` → `def`; implicit cast `def` to `double 7.0` → `double 7.0`; load from `x` → `int 5`; promote `int 5` and `double 7.0`: result `double`; implicit cast `int 5` to `double 5.0` → `double 5.0`; greater than or equal `double 5.0` and `double 7.0` → `boolean false`; implicit cast `boolean false` to `def` → `def`; store `def` to `z`

Less Than

edit

Use the less than operator '<' to COMPARE two numeric type values where a resultant boolean type value is true if the left-hand side value is less than to the right-hand side value and false otherwise.

Errors

If either the evaluated left-hand side or the evaluated right-hand side is a non-numeric value.

Grammar

less_than: expression '<' expression;

Promotion

	byte	short	char	int	long	float	double	def
byte	int	int	int	int	long	float	double	def
short	int	int	int	int	long	float	double	def
char	int	int	int	int	long	float	double	def
int	int	int	int	int	long	float	double	def
long	long	long	long	long	long	float	double	def
float	float	float	float	float	float	float	double	def
double	double	double	double	double	double	double	double	def
def	def	def	def	def	def	def	def	def

Examples

Less than with different numeric types.

boolean x = 5 < 4; 
double y = 6.0;    
x = 6 < y;

	declare `boolean x`; less than `int 5` and `int 4` → `boolean false`; store `boolean false` to `x`
	declare `double y`; store `double 6.0` to `y`
	load from `y` → `double 6.0 @0`; promote `int 6` and `double 6.0`: result `double`; implicit cast `int 6` to `double 6.0 @1` → `double 6.0 @1`; less than `double 6.0 @1` and `double 6.0 @0` → `boolean false`; store `boolean false` to `x`

Less than with the def type.

int x = 5;       
def y = 7.0;     
def z = y < 6.5; 
def a = x < y;

	declare `int x`; store `int 5` to `x`
	declare `def y`; implicit cast `double 7.0` to `def` → `def`; store `def` to `y`
	declare `def z`; load from `y` → `def`; implicit cast `def` to `double 7.0` → `double 7.0`; less than `double 7.0` and `double 6.5` → `boolean false`; implicit cast `boolean false` to `def` → `def`; store `def` to `z`
	declare `def a`; load from `y` → `def`; implicit cast `def` to `double 7.0` → `double 7.0`; load from `x` → `int 5`; promote `int 5` and `double 7.0`: result `double`; implicit cast `int 5` to `double 5.0` → `double 5.0`; less than `double 5.0` and `double 7.0` → `boolean true`; implicit cast `boolean true` to `def` → `def`; store `def` to `z`

Less Than Or Equal

edit

Use the less than or equal operator '<=' to COMPARE two numeric type values where a resultant boolean type value is true if the left-hand side value is less than or equal to the right-hand side value and false otherwise.

Errors

If either the evaluated left-hand side or the evaluated right-hand side is a non-numeric value.

Grammar

greater_than_or_equal: expression '<=' expression;

Promotion

	byte	short	char	int	long	float	double	def
byte	int	int	int	int	long	float	double	def
short	int	int	int	int	long	float	double	def
char	int	int	int	int	long	float	double	def
int	int	int	int	int	long	float	double	def
long	long	long	long	long	long	float	double	def
float	float	float	float	float	float	float	double	def
double	double	double	double	double	double	double	double	def
def	def	def	def	def	def	def	def	def

Examples

Less than or equal with different numeric types.

boolean x = 5 <= 4; 
double y = 6.0;     
x = 6 <= y;

	declare `boolean x`; less than or equal `int 5` and `int 4` → `boolean false`; store `boolean true` to `x`
	declare `double y`; store `double 6.0` to `y`
	load from `y` → `double 6.0 @0`; promote `int 6` and `double 6.0`: result `double`; implicit cast `int 6` to `double 6.0 @1` → `double 6.0 @1`; less than or equal `double 6.0 @1` and `double 6.0 @0` → `boolean true`; store `boolean true` to `x`

Less than or equal with the def type.

int x = 5;        
def y = 7.0;      
def z = y <= 7.0; 
def a = x <= y;

	declare `int x`; store `int 5` to `x`;
	declare `def y`; implicit cast `double 7.0` to `def` → `def`; store `def` to `y`;
	declare `def z`; load from `y` → `def`; implicit cast `def` to `double 7.0 @0` → `double 7.0 @0`; less than or equal `double 7.0 @0` and `double 7.0 @1` → `boolean true`; implicit cast `boolean true` to `def` → `def`; store `def` to `z`
	declare `def a`; load from `y` → `def`; implicit cast `def` to `double 7.0` → `double 7.0`; load from `x` → `int 5`; promote `int 5` and `double 7.0`: result `double`; implicit cast `int 5` to `double 5.0` → `double 5.0`; less than or equal `double 5.0` and `double 7.0` → `boolean true`; implicit cast `boolean true` to `def` → `def`; store `def` to `z`

Instanceof

edit

Use the instanceof operator to COMPARE the variable/field type to a specified reference type using the reference type name where a resultant boolean type value is true if the variable/field type is the same as or a descendant of the specified reference type and false otherwise.

Errors

If the reference type name doesn’t exist as specified by the right-hand side.

Grammar

instance_of: ID 'instanceof' TYPE;

Examples

Instance of with different reference types.

Map m = new HashMap();            
boolean a = m instanceof HashMap; 
boolean b = m instanceof Map;

	declare `Map m`; allocate `HashMap` instance → `HashMap reference`; implicit cast `HashMap reference` to `Map reference`; store `Map reference` to `m`
	declare `boolean a`; load from `m` → `Map reference`; implicit cast `Map reference` to `HashMap reference` → `HashMap reference`; instanceof `HashMap reference` and `HashMap` → `boolean true`; store `boolean true` to `a`
	declare `boolean b`; load from `m` → `Map reference`; implicit cast `Map reference` to `HashMap reference` → `HashMap reference`; instanceof `HashMap reference` and `Map` → `boolean true`; store `true` to `b`; (note `HashMap` is a descendant of `Map`)

Instance of with the def type.

def d = new ArrayList();       
boolean a = d instanceof List; 
boolean b = d instanceof Map;

	declare `def d`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `def` → `def`; store `def` to `d`
	declare `boolean a`; load from `d` → `def`; implicit cast `def` to `ArrayList reference` → `ArrayList reference`; instanceof `ArrayList reference` and `List` → `boolean true`; store `boolean true` to `a`; (note `ArrayList` is a descendant of `List`)
	declare `boolean b`; load from `d` → `def`; implicit cast `def` to `ArrayList reference` → `ArrayList reference`; instanceof `ArrayList reference` and `Map` → `boolean false`; store `boolean false` to `a`; (note `ArrayList` is not a descendant of `Map`)

Equality Equals

edit

Use the equality equals operator '==' to COMPARE two values where a resultant boolean type value is true if the two values are equal and false otherwise. The member method, equals, is implicitly called when the values are reference type values where the first value is the target of the call and the second value is the argument. This operation is null-safe where if both values are null the resultant boolean type value is true, and if only one value is null the resultant boolean type value is false. A valid comparison is between boolean type values, numeric type values, or reference type values.

Errors

If a comparison is made between a boolean type value and numeric type value.
If a comparison is made between a primitive type value and a reference type value.

Grammar

equality_equals: expression '==' expression;

Promotion

	boolean	byte	short	char	int	long	float	double	Reference	def
boolean	boolean	-	-	-	-	-	-	-	-	def
byte	-	int	int	int	int	long	float	double	-	def
short	-	int	int	int	int	long	float	double	-	def
char	-	int	int	int	int	long	float	double	-	def
int	-	int	int	int	int	long	float	double	-	def
long	-	long	long	long	long	long	float	double	-	def
float	-	float	float	float	float	float	float	double	-	def
double	-	double	double	double	double	double	double	double	-	def
Reference	-	-	-	-	-	-	-	-	Object	def
def	def	def	def	def	def	def	def	def	def	def

Examples

Equality equals with the boolean type.

boolean a = true;  
boolean b = false; 
a = a == false;    
b = a == b;

	declare `boolean a`; store `boolean true` to `a`
	declare `boolean b`; store `boolean false` to `b`
	load from `a` → `boolean true`; equality equals `boolean true` and `boolean false` → `boolean false`; store `boolean false` to `a`
	load from `a` → `boolean false @0`; load from `b` → `boolean false @1`; equality equals `boolean false @0` and `boolean false @1` → `boolean false`; store `boolean false` to `b`

Equality equals with primitive types.

int a = 1;          
double b = 2.0;     
boolean c = a == b; 
c = 1 == a;

	declare `int a`; store `int 1` to `a`
	declare `double b`; store `double 1.0` to `b`
	declare `boolean c`; load from `a` → `int 1`; load from `b` → `double 2.0`; promote `int 1` and `double 2.0`: result `double`; implicit cast `int 1` to `double 1.0` → double `1.0; equality equals `double 1.0` and `double 2.0` → `boolean false`; store `boolean false` to `c`
	load from `a` → `int 1 @1`; equality equals `int 1 @0` and `int 1 @1` → `boolean true`; store `boolean true` to `c`

Equal equals with reference types.

List a = new ArrayList(); 
List b = new ArrayList(); 
a.add(1);                 
boolean c = a == b;       
b.add(1);                 
c = a == b;

	declare `List a`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `List reference` → `List reference`; store `List reference` to `a`
	declare `List b`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `List reference` → `List reference`; store `List reference` to `b`
	load from `a` → `List reference`; call `add` on `List reference` with arguments (`int 1)`
	declare `boolean c`; load from `a` → `List reference @0`; load from `b` → `List reference @1`; call `equals` on `List reference @0` with arguments (`List reference @1`) → `boolean false`; store `boolean false` to `c`
	load from `b` → `List reference`; call `add` on `List reference` with arguments (`int 1`)
	load from `a` → `List reference @0`; load from `b` → `List reference @1`; call `equals` on `List reference @0` with arguments (`List reference @1`) → `boolean true`; store `boolean true` to `c`

Equality equals with null.

Object a = null;       
Object b = null;       
boolean c = a == null; 
c = a == b;            
b = new Object();      
c = a == b;

	declare `Object a`; store `null` to `a`
	declare `Object b`; store `null` to `b`
	declare `boolean c`; load from `a` → `null @0`; equality equals `null @0` and `null @1` → `boolean true`; store `boolean true` to `c`
	load from `a` → `null @0`; load from `b` → `null @1`; equality equals `null @0` and `null @1` → `boolean true`; store `boolean true` to `c`
	allocate `Object` instance → `Object reference`; store `Object reference` to `b`
	load from `a` → `Object reference`; load from `b` → `null`; call `equals` on `Object reference` with arguments (`null`) → `boolean false`; store `boolean false` to `c`

Equality equals with the def type.

def a = 0;               
def b = 1;               
boolean c = a == b;      
def d = new HashMap();   
def e = new ArrayList(); 
c = d == e;

	declare `def a`; implicit cast `int 0` to `def` → `def`; store `def` to `a`;
	declare `def b`; implicit cast `int 1` to `def` → `def`; store `def` to `b`;
	declare `boolean c`; load from `a` → `def`; implicit cast `a` to `int 0` → `int 0`; load from `b` → `def`; implicit cast `b` to `int 1` → `int 1`; equality equals `int 0` and `int 1` → `boolean false`; store `boolean false` to `c`
	declare `def d`; allocate `HashMap` instance → `HashMap reference`; implicit cast `HashMap reference` to `def` → `def` store `def` to `d`;
	declare `def e`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `def` → `def` store `def` to `d`;
	load from `d` → `def`; implicit cast `def` to `HashMap reference` → `HashMap reference`; load from `e` → `def`; implicit cast `def` to `ArrayList reference` → `ArrayList reference`; call `equals` on `HashMap reference` with arguments (`ArrayList reference`) → `boolean false`; store `boolean false` to `c`

Equality Not Equals

edit

Use the equality not equals operator '!=' to COMPARE two values where a resultant boolean type value is true if the two values are NOT equal and false otherwise. The member method, equals, is implicitly called when the values are reference type values where the first value is the target of the call and the second value is the argument with the resultant boolean type value flipped. This operation is null-safe where if both values are null the resultant boolean type value is false, and if only one value is null the resultant boolean type value is true. A valid comparison is between boolean type values, numeric type values, or reference type values.

Errors

If a comparison is made between a boolean type value and numeric type value.
If a comparison is made between a primitive type value and a reference type value.

Grammar

equality_not_equals: expression '!=' expression;

Promotion

	boolean	byte	short	char	int	long	float	double	Reference	def
boolean	boolean	-	-	-	-	-	-	-	-	def
byte	-	int	int	int	int	long	float	double	-	def
short	-	int	int	int	int	long	float	double	-	def
char	-	int	int	int	int	long	float	double	-	def
int	-	int	int	int	int	long	float	double	-	def
long	-	long	long	long	long	long	float	double	-	def
float	-	float	float	float	float	float	float	double	-	def
double	-	double	double	double	double	double	double	double	-	def
Reference	-	-	-	-	-	-	-	-	Object	def
def	def	def	def	def	def	def	def	def	def	def

Examples

Equality not equals with the boolean type.

boolean a = true;  
boolean b = false; 
a = a != false;    
b = a != b;

	declare `boolean a`; store `boolean true` to `a`
	declare `boolean b`; store `boolean false` to `b`
	load from `a` → `boolean true`; equality not equals `boolean true` and `boolean false` → `boolean true`; store `boolean true` to `a`
	load from `a` → `boolean true`; load from `b` → `boolean false`; equality not equals `boolean true` and `boolean false` → `boolean true`; store `boolean true` to `b`

Equality not equals with primitive types.

int a = 1;          
double b = 2.0;     
boolean c = a != b; 
c = 1 != a;

	declare `int a`; store `int 1` to `a`
	declare `double b`; store `double 1.0` to `b`
	declare `boolean c`; load from `a` → `int 1`; load from `b` → `double 2.0`; promote `int 1` and `double 2.0`: result `double`; implicit cast `int 1` to `double 1.0` → double `1.0; equality not equals `double 1.0` and `double 2.0` → `boolean true`; store `boolean true` to `c`
	load from `a` → `int 1 @1`; equality not equals `int 1 @0` and `int 1 @1` → `boolean false`; store `boolean false` to `c`

Equality not equals with reference types.

List a = new ArrayList(); 
List b = new ArrayList(); 
a.add(1);                 
boolean c = a == b;       
b.add(1);                 
c = a == b;

	declare `List a`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `List reference` → `List reference`; store `List reference` to `a`
	declare `List b`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `List reference` → `List reference`; store `List reference` to `b`
	load from `a` → `List reference`; call `add` on `List reference` with arguments (`int 1)`
	declare `boolean c`; load from `a` → `List reference @0`; load from `b` → `List reference @1`; call `equals` on `List reference @0` with arguments (`List reference @1`) → `boolean false`; boolean not `boolean false` → `boolean true` store `boolean true` to `c`
	load from `b` → `List reference`; call `add` on `List reference` with arguments (`int 1`)
	load from `a` → `List reference @0`; load from `b` → `List reference @1`; call `equals` on `List reference @0` with arguments (`List reference @1`) → `boolean true`; boolean not `boolean true` → `boolean false`; store `boolean false` to `c`

Equality not equals with null.

Object a = null;       
Object b = null;       
boolean c = a == null; 
c = a == b;            
b = new Object();      
c = a == b;

	declare `Object a`; store `null` to `a`
	declare `Object b`; store `null` to `b`
	declare `boolean c`; load from `a` → `null @0`; equality not equals `null @0` and `null @1` → `boolean false`; store `boolean false` to `c`
	load from `a` → `null @0`; load from `b` → `null @1`; equality not equals `null @0` and `null @1` → `boolean false`; store `boolean false` to `c`
	allocate `Object` instance → `Object reference`; store `Object reference` to `b`
	load from `a` → `Object reference`; load from `b` → `null`; call `equals` on `Object reference` with arguments (`null`) → `boolean false`; boolean not `boolean false` → `boolean true`; store `boolean true` to `c`

Equality not equals with the def type.

def a = 0;               
def b = 1;               
boolean c = a == b;      
def d = new HashMap();   
def e = new ArrayList(); 
c = d == e;

	declare `def a`; implicit cast `int 0` to `def` → `def`; store `def` to `a`;
	declare `def b`; implicit cast `int 1` to `def` → `def`; store `def` to `b`;
	declare `boolean c`; load from `a` → `def`; implicit cast `a` to `int 0` → `int 0`; load from `b` → `def`; implicit cast `b` to `int 1` → `int 1`; equality equals `int 0` and `int 1` → `boolean false`; store `boolean false` to `c`
	declare `def d`; allocate `HashMap` instance → `HashMap reference`; implicit cast `HashMap reference` to `def` → `def` store `def` to `d`;
	declare `def e`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `def` → `def` store `def` to `d`;
	load from `d` → `def`; implicit cast `def` to `HashMap reference` → `HashMap reference`; load from `e` → `def`; implicit cast `def` to `ArrayList reference` → `ArrayList reference`; call `equals` on `HashMap reference` with arguments (`ArrayList reference`) → `boolean false`; store `boolean false` to `c`

Identity Equals

edit

Use the identity equals operator '===' to COMPARE two values where a resultant boolean type value is true if the two values are equal and false otherwise. A reference type value is equal to another reference type value if both values refer to same instance on the heap or if both values are null. A valid comparison is between boolean type values, numeric type values, or reference type values.

Errors

If a comparison is made between a boolean type value and numeric type value.
If a comparison is made between a primitive type value and a reference type value.

Grammar

identity_equals: expression '===' expression;

Promotion

	boolean	byte	short	char	int	long	float	double	Reference	def
boolean	boolean	-	-	-	-	-	-	-	-	def
byte	-	int	int	int	int	long	float	double	-	def
short	-	int	int	int	int	long	float	double	-	def
char	-	int	int	int	int	long	float	double	-	def
int	-	int	int	int	int	long	float	double	-	def
long	-	long	long	long	long	long	float	double	-	def
float	-	float	float	float	float	float	float	double	-	def
double	-	double	double	double	double	double	double	double	-	def
Reference	-	-	-	-	-	-	-	-	Object	def
def	def	def	def	def	def	def	def	def	def	def

Examples

Identity equals with reference types.

List a = new ArrayList(); 
List b = new ArrayList(); 
List c = a;               
boolean c = a === b;      
c = a === c;

	declare `List a`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `List reference` → `List reference`; store `List reference` to `a`
	declare `List b`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `List reference` → `List reference`; store `List reference` to `b`
	load from `a` → `List reference`; store `List reference` to `c`
	declare `boolean c`; load from `a` → `List reference @0`; load from `b` → `List reference @1`; identity equals `List reference @0` and `List reference @1` → `boolean false` store `boolean false` to `c`
	load from `a` → `List reference @0`; load from `c` → `List reference @1`; identity equals `List reference @0` and `List reference @1` → `boolean true` store `boolean true` to `c` (note `List reference @0` and `List reference @1` refer to the same instance)

Identity equals with null.

Object a = null;        
Object b = null;        
boolean c = a === null; 
c = a === b;            
b = new Object();       
c = a === b;

	declare `Object a`; store `null` to `a`
	declare `Object b`; store `null` to `b`
	declare `boolean c`; load from `a` → `null @0`; identity equals `null @0` and `null @1` → `boolean true`; store `boolean true` to `c`
	load from `a` → `null @0`; load from `b` → `null @1`; identity equals `null @0` and `null @1` → `boolean true`; store `boolean true` to `c`
	allocate `Object` instance → `Object reference`; store `Object reference` to `b`
	load from `a` → `Object reference`; load from `b` → `null`; identity equals `Object reference` and `null` → `boolean false`; store `boolean false` to `c`

Identity equals with the def type.

def a = new HashMap();   
def b = new ArrayList(); 
boolean c = a === b;     
b = a;                   
c = a === b;

	declare `def d`; allocate `HashMap` instance → `HashMap reference`; implicit cast `HashMap reference` to `def` → `def` store `def` to `d`
	declare `def e`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `def` → `def` store `def` to `d`
	declare `boolean c`; load from `a` → `def`; implicit cast `def` to `HashMap reference` → `HashMap reference`; load from `b` → `def`; implicit cast `def` to `ArrayList reference` → `ArrayList reference`; identity equals `HashMap reference` and `ArrayList reference` → `boolean false`; store `boolean false` to `c`
	load from `a` → `def`; store `def` to `b`
	load from `a` → `def`; implicit cast `def` to `HashMap reference @0` → `HashMap reference @0`; load from `b` → `def`; implicit cast `def` to `HashMap reference @1` → `HashMap reference @1`; identity equals `HashMap reference @0` and `HashMap reference @1` → `boolean true`; store `boolean true` to `b`; (note `HashMap reference @0` and `HashMap reference @1` refer to the same instance)

Identity Not Equals

edit

Use the identity not equals operator '!==' to COMPARE two values where a resultant boolean type value is true if the two values are NOT equal and false otherwise. A reference type value is not equal to another reference type value if both values refer to different instances on the heap or if one value is null and the other is not. A valid comparison is between boolean type values, numeric type values, or reference type values.

Errors

If a comparison is made between a boolean type value and numeric type value.
If a comparison is made between a primitive type value and a reference type value.

Grammar

identity_not_equals: expression '!==' expression;

Promotion

	boolean	byte	short	char	int	long	float	double	Reference	def
boolean	boolean	-	-	-	-	-	-	-	-	def
byte	-	int	int	int	int	long	float	double	-	def
short	-	int	int	int	int	long	float	double	-	def
char	-	int	int	int	int	long	float	double	-	def
int	-	int	int	int	int	long	float	double	-	def
long	-	long	long	long	long	long	float	double	-	def
float	-	float	float	float	float	float	float	double	-	def
double	-	double	double	double	double	double	double	double	-	def
Reference	-	-	-	-	-	-	-	-	Object	def
def	def	def	def	def	def	def	def	def	def	def

Examples

Identity not equals with reference type values.

List a = new ArrayList(); 
List b = new ArrayList(); 
List c = a;               
boolean c = a !== b;      
c = a !== c;

	declare `List a`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `List reference` → `List reference`; store `List reference` to `a`
	declare `List b`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `List reference` → `List reference`; store `List reference` to `b`
	load from `a` → `List reference`; store `List reference` to `c`
	declare `boolean c`; load from `a` → `List reference @0`; load from `b` → `List reference @1`; identity not equals `List reference @0` and `List reference @1` → `boolean true` store `boolean true` to `c`
	load from `a` → `List reference @0`; load from `c` → `List reference @1`; identity not equals `List reference @0` and `List reference @1` → `boolean false` store `boolean false` to `c` (note `List reference @0` and `List reference @1` refer to the same instance)

Identity not equals with null.

Object a = null;        
Object b = null;        
boolean c = a !== null; 
c = a !== b;            
b = new Object();       
c = a !== b;

	declare `Object a`; store `null` to `a`
	declare `Object b`; store `null` to `b`
	declare `boolean c`; load from `a` → `null @0`; identity not equals `null @0` and `null @1` → `boolean false`; store `boolean false` to `c`
	load from `a` → `null @0`; load from `b` → `null @1`; identity not equals `null @0` and `null @1` → `boolean false`; store `boolean false` to `c`
	allocate `Object` instance → `Object reference`; store `Object reference` to `b`
	load from `a` → `Object reference`; load from `b` → `null`; identity not equals `Object reference` and `null` → `boolean true`; store `boolean true` to `c`

Identity not equals with the def type.

def a = new HashMap();   
def b = new ArrayList(); 
boolean c = a !== b;     
b = a;                   
c = a !== b;

	declare `def d`; allocate `HashMap` instance → `HashMap reference`; implicit cast `HashMap reference` to `def` → `def` store `def` to `d`
	declare `def e`; allocate `ArrayList` instance → `ArrayList reference`; implicit cast `ArrayList reference` to `def` → `def` store `def` to `d`
	declare `boolean c`; load from `a` → `def`; implicit cast `def` to `HashMap reference` → `HashMap reference`; load from `b` → `def`; implicit cast `def` to `ArrayList reference` → `ArrayList reference`; identity not equals `HashMap reference` and `ArrayList reference` → `boolean true`; store `boolean true` to `c`
	load from `a` → `def`; store `def` to `b`
	load from `a` → `def`; implicit cast `def` to `HashMap reference @0` → `HashMap reference @0`; load from `b` → `def`; implicit cast `def` to `HashMap reference @1` → `HashMap reference @1`; identity not equals `HashMap reference @0` and `HashMap reference @1` → `boolean false`; store `boolean false` to `b`; (note `HashMap reference @0` and `HashMap reference @1` refer to the same instance)

Boolean Xor

edit

Use the boolean xor operator '^' to XOR together two boolean type values where if one boolean type value is true and the other is false the resultant boolean type value is true and false otherwise.

Errors

If either evaluated value is a value other than a boolean type value or a value that is castable to a boolean type value.

Truth

	true	false
true	false	true
false	true	false

Grammar

boolean_xor: expression '^' expression;

Examples

Boolean xor with the boolean type.

boolean x = false;    
boolean y = x ^ true; 
y = y ^ x;

	declare `boolean x`; store `boolean false` to `x`
	declare `boolean y`; load from `x` → `boolean false` boolean xor `boolean false` and `boolean true` → `boolean true`; store `boolean true` to `y`
	load from `y` → `boolean true @0`; load from `x` → `boolean true @1`; boolean xor `boolean true @0` and `boolean true @1` → `boolean false`; store `boolean false` to `y`

Boolean xor with the def type.

def x = false;    
def y = x ^ true; 
y = y ^ x;

	declare `def x`; implicit cast `boolean false` to `def` → `def`; store `def` to `x`
	declare `def y`; load from `x` → `def`; implicit cast `def` to `boolean false` → `boolean false`; boolean xor `boolean false` and `boolean true` → `boolean true`; implicit cast `boolean true` to `def` → `def`; store `def` to `y`
	load from `y` → `def`; implicit cast `def` to `boolean true @0` → `boolean true @0`; load from `x` → `def`; implicit cast `def` to `boolean true @1` → `boolean true @1`; boolean xor `boolean true @0` and `boolean true @1` → `boolean false`; implicit cast `boolean false` → `def`; store `def` to `y`

Boolean And

edit

Use the boolean and operator '&&' to AND together two boolean type values where if both boolean type values are true the resultant boolean type value is true and false otherwise.

Errors

If either evaluated value is a value other than a boolean type value or a value that is castable to a boolean type value.

Truth

	true	false
true	true	false
false	false	false

Grammar

boolean_and: expression '&&' expression;

Examples

Boolean and with the boolean type.

boolean x = true;      
boolean y = x && true; 
x = false;             
y = y && x;

	declare `boolean x`; store `boolean true` to `x`
	declare `boolean y`; load from `x` → `boolean true @0`; boolean and `boolean true @0` and `boolean true @1` → `boolean true`; store `boolean true` to `y`
	store `boolean false` to `x`
	load from `y` → `boolean true`; load from `x` → `boolean false`; boolean and `boolean true` and `boolean false` → `boolean false`; store `boolean false` to `y`

Boolean and with the def type.

def x = true;      
def y = x && true; 
x = false;         
y = y && x;

	declare `def x`; implicit cast `boolean true` to `def` → `def`; store `def` to `x`
	declare `def y`; load from `x` → `def`; implicit cast `def` to `boolean true @0` → `boolean true @0`; boolean and `boolean true @0` and `boolean true @1` → `boolean true`; implicit cast `boolean true` to `def` → `def`; store `def` to `y`
	implicit cast `boolean false` to `def` → `def`; store `def` to `x`;
	load from `y` → `def`; implicit cast `def` to `boolean true` → `boolean true`; load from `x` → `def`; implicit cast `def` to `boolean false` → `boolean false`; boolean and `boolean true` and `boolean false` → `boolean false`; implicit cast `boolean false` → `def`; store `def` to `y`

Boolean Or

edit

Use the boolean or operator '||' to OR together two boolean type values where if either one of the boolean type values is true the resultant boolean type value is true and false otherwise.

Errors

If either evaluated value is a value other than a boolean type value or a value that is castable to a boolean type value.

Truth

	true	false
true	true	true
false	true	false

Grammar:

boolean_and: expression '||' expression;

Examples

Boolean or with the boolean type.

boolean x = false;     
boolean y = x || true; 
y = false;             
y = y || x;

	declare `boolean x`; store `boolean false` to `x`
	declare `boolean y`; load from `x` → `boolean false`; boolean or `boolean false` and `boolean true` → `boolean true`; store `boolean true` to `y`
	store `boolean false` to `y`
	load from `y` → `boolean false @0`; load from `x` → `boolean false @1`; boolean or `boolean false @0` and `boolean false @1` → `boolean false`; store `boolean false` to `y`

Boolean or with the def type.

def x = false;     
def y = x || true; 
y = false;         
y = y || x;

	declare `def x`; implicit cast `boolean false` to `def` → `def`; store `def` to `x`
	declare `def y`; load from `x` → `def`; implicit cast `def` to `boolean false` → `boolean true`; boolean or `boolean false` and `boolean true` → `boolean true`; implicit cast `boolean true` to `def` → `def`; store `def` to `y`
	implicit cast `boolean false` to `def` → `def`; store `def` to `y`;
	load from `y` → `def`; implicit cast `def` to `boolean false @0` → `boolean false @0`; load from `x` → `def`; implicit cast `def` to `boolean false @1` → `boolean false @1`; boolean or `boolean false @0` and `boolean false @1` → `boolean false`; implicit cast `boolean false` → `def`; store `def` to `y`

« Operators: Numeric Operators: Reference »