custom-operators.md

dyvil	v0.31.0

Custom Operators

Custom Operators can be defined in Header Files or in the header of a class file. Note that it is not possible to define custom operators anywhere else.

The following syntax is used to define a custom operator:

1. The type of operator
   • infix
   • prefix
   • postfix
2. The keyword operator
3. The symbol
4. An secondary symbol for ternary operators and circumfix operators - only valid after infix operator or prefix postfix operator
5. An optional list of additional comma-separated properties within curly braces. Allowed properties:
   • precedence followed by an integer literal
   • associativity followed by one of
     • none
     • left
     • right

Example:

prefix  operator &
postfix operator ^

infix operators also need additional properties to be fully defined, namely a precedence value and an associativity type.

You can define these properties in curly brackets after the name of the operator:

infix operator +- { none,             120 }
//                  ^ associativity   ^ precedence

It is optional, but recommended for clarity, to type out which property is being defined:

infix operator +- { associativity none, precedence 120 }
infix operator +- { associativity none,            120 }
infix operator +- {               none, precedence 120 }

The order in which the properties are placed within the brackets does not matter. Duplicate properties are not permitted and will cause a diagnostic error.