Pyro

A scripting language for people who enjoy the simpler things in life.

Version 0.3.2

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 not Right
Bitwise and or xor >> << Left
Multiplication * / // % Left
Addition + - Left
Comparison > >= < <= Left
Equality == != Left
Logical && || ?? !! Left
Conditional ?| None
Assignment = += -= Right

Note that conditional expressions using the ternary operator ?| can't be nested. (Checkmate, Satan.)

Logical Operators

The logical operators || and && are short-circuiting and evaluate the truthiness of their operands.

The value of the logical-OR 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:

var foo = maybe_falsey() || "default";

The value of the logical-AND expresson 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:

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. (I can't think of a good reason to use this but I still want to.)

The Conditional Operator

The conditional or ternary operator takes three operands. It looks like this:

var foo = condition ? expr1 | expr2;

The value of the expression is expr1 if condition evaluates as truthy, otherwise expr2.

The Null-coalescing Operator

The null-coalescing operator ?? lets you swap in a default value in place of a null:

var foo = 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.

The Error-coalescing Operator

The error-coalescing operator !! lets you swap in a default value in place of an error:

var foo = 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.