Operators
 Operator Precedence
 Mathematical Operators
 Equality & Comparison Operators
 Logical Operators
 The Conditional Operator
 The Nullcoalescing Operator
 The Errorcoalescing Operator
 The Elsecoalescing Operator
 Assignment Operators
 Overloading Operators
Operator Precedence
Operator precedence in the table below goes from high at the top to low at the bottom. Operators at the same level have the same precedence.
Level  Operators  Associativity 

Call 
() [] . : ::

Left 
Power 
**

Right 
Unary 
! +  ~ try

Right 
Bitwise 
&  ^ >> <<

Left 
Multiplication 
* / // %

Left 
Addition 
+ 

Left 
Comparison 
> >= < <= in

Left 
Equality 
== !=

Left 
Logical 
&&  ?? !! else

Left 
Conditional 
? :

None 
Assignment 
= += =

Right 
Note that conditional expressions using the ternary operator ? :
can't be nested. (Checkmate, Satan.)
Mathematical Operators
+

Addition (binary) or a noop (unary). Addition returns an integer if both operands are integers or a float if either or both are floats. 


Subtraction (binary) or negation (unary). Subtraction returns an integer if both operands are integers or a float if either or both are floats. 
*

Multiplication. Returns an integer if both operands are integers or a float if either or both are floats. 
/

Floatingpoint division. Both operands will be converted to floats and the result will be a float. 
//

Truncating division. Returns an integer if both operands are integers or a float if either or both are floats. 
%

Modulo/remainder operator. Returns an integer if both operands are integers or a float if either or both are floats. 
**

Power operator. Both operands are converted to floats and the result is a float. 
Pyro also has a set of builtin functions for performing checked arithmetic with integers.
You can overload the mathematical operators to customize their behaviour for your own types.
Equality & Comparison Operators
The equality (==
, !=
) and comparison (>
, >=
, <
, <=
) operators each take two operands and evaluate to a boolean.
 Numbers are equal if their values are numerically equal.
 Strings are equal if they have the same content.
 Tuples are equal if they have the same length and their elements are equal.
 Sets are equal if they are setequivalent, i.e. if they contain the same items in any order.
 By default, all other objects are equal only if they are the same object.
You can overload the equality and comparison operators to customize their behaviour for your own types.
Logical Operators
The logical operators are 
(OR), &&
(AND), and !
(NOT). They evaluate the truthiness of their operands.
In Pyro, the values false
, null
, and err
are falsey; all other values are truthy.
The logical operators 
and &&
are valuepreserving and shortcircuiting.
The value of the logicalOR expression a  b
is the value of the first operand if that operand is truthy, otherwise the value of the second operand.
This means you can use the 
operator to swap in a default value in place of a falsey expression, e.g.
var value = maybe_falsey()  "default";
Note that you can chain multiple 
expressions, e.g.
var value = maybe_falsey()  get_fallback()  "default";
The value of the logicalAND expression a && b
is the value of the first operand if that operand is falsey, otherwise the value of the second operand.
This means you can use the &&
operator to conditionally chain a sequence of expressions, e.g.
func1() && func2();
func2()
will only be called if func1()
returns a truthy value.
Note that you can chain multiple &&
expressions, e.g.
func1() && func2() && func3();
func2()
will only be called if func1()
returns a truthy value; func3()
will only be called if func2()
returns a truthy value.
The Conditional Operator
The conditional or ternary operator takes three operands. It looks like this:
var value = condition ? expr1 : expr2;
The value of the conditional expression is expr1
if condition
evaluates as truthy, otherwise expr2
.
The Nullcoalescing Operator
The nullcoalescing operator ??
lets you swap in a default value in place of a null
:
var value = maybe_null() ?? "default";
The value of the expression a ?? b
is the value of the first operand if that operand is not null
, otherwise the value of the second operand.
You can chain multiple ??
expressions, e.g.
var value = maybe_null() ?? get_fallback() ?? "default";
The Errorcoalescing Operator
The errorcoalescing operator !!
lets you swap in a default value in place of an error:
var value = maybe_error() !! "default";
The value of the expression a !! b
is the value of the first operand if that operand is not an err
, otherwise the value of the second operand.
You can chain multiple !!
expressions, e.g.
var value = maybe_error() ?? get_fallback() ?? "default";
The Elsecoalescing Operator
The elsecoalescing operator else
lets you swap in a default value in place of a broadlydefined falseyish value:
var value = get_value() else "default";
The value of the expression a else b
is the value of the first operand if that value is not one of (false
, null
, err
, 0
, 0.0
, or ""
), otherwise the value of the second operand.
You can chain multiple else
expressions, e.g.
var value = get_value() else get_fallback() else "default";
Assignment Operators
An assignment expression, a = b
, returns the value assigned, e.g.
var foo; var bar = (foo = 5); assert bar == 5;
Assignment using a compound assignment operator, e.g.
foo += bar;
is equivalent to the longform expression:
foo = foo + bar;
Compound assignment operators cannot be overloaded independently of their base operators — i.e. overloading +
automatically overloads +=
;
Overloading Operators
The following operators can be overloaded by userdefined types:

()

[]

==

<

<=

>

>=

+
(binary/unary) 

(binary/unary) 
*

**

/

//

%

&



^

~

<<

>>
You can overload these operators using the $
prefixed methods listed here.