Memory annotations

The Swan language supports memory annotations to specify how data is stored and accessed in memory.

Table 10 Memory annotations

Annotation	Description	Class
! expr	Bang unary operator for duplicate permission	UnaryExpr with UnaryOp.Bang operator
var_id * [: type]	Starred input which value can be modified in place by an output.	VarDecl, property is_starred=True
var_id at ID [: type]	Output variable which value is stored at a specific memory location, corresponding to an input.	VarDecl, property at=ID
(expr with * modifier {{ ; modifier }} [[ ; ]])	Copy with modification, replacing functional update.	FunctionalUpdate, property is_starred=True
(expr at ID)	Expression stored at a specific memory location.	Expression, property at=ID. This property is defined for all expressions.