Use decimal directive

The use decimal pragma is used to provide a DecimalContext instance at the surrounding frame for configuring the decimal data type.

var ctx:DecimalContext, x:decimal

ctx = new DecimalContext(12, "half_even") // 12 digits of precision,
                                          //   round to even

{
    use decimal ctx
    x = a + b         // "+" rounds to even if necessary
}

This affects not only the lexical scope, but also external function calls that are called subsequently from the same scope or nested scopes during runtime.

Note: Internally functions receive a hierarchical environment frame reference, which is decently optimized, where every frame contains a ?context local that includes a DecimalContext reference that may be a null pointer (which means skip to parent frame).

Thus, that syntactic construct should work with both synchronous and asynchronous code.

Syntax

UseDecimalDirective :
use decimal ListExpression^allowIn