hashicorp/hcl v2.3.0 on GitHub

ext/tryfunc: Optional functions try and can to include in your hcl.EvalContext when evaluating expressions, which allow users to make decisions based on the success of expressions. (#330)
ext/typeexpr: Now has an optional function convert which you can include in your hcl.EvalContext when evaluating expressions, allowing users to convert values to specific type constraints using the type constraint expression syntax. (#330)
ext/typeexpr: A new cty capsule type typeexpr.TypeConstraintType which, when used as either a type constraint for a function parameter or as a type constraint for a hcldec attribute specification will cause the given expression to be interpreted as a type constraint expression rather than a value expression. (#330)
ext/customdecode: An optional extension that allows overriding the static decoding behavior for expressions either in function arguments or hcldec attribute specifications. (#330)
ext/customdecode: New cty capsuletypes customdecode.ExpressionType and customdecode.ExpressionClosureType which, when used as either a type constraint for a function parameter or as a type constraint for a hcldec attribute specification will cause the given expression (and, for the closure type, also the hcl.EvalContext it was evaluated in) to be captured for later analysis, rather than immediately evaluated. (#330)