use crate::Value;
/// A language expression/predicate reference resolved by the runtime.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct LanguageExpressionDef {
pub language: String,
pub source: String,
}
/// A declarative value source for set_header / set_body.
#[derive(Debug, Clone, PartialEq)]
pub enum ValueSourceDef {
Literal(Value),
Expression(LanguageExpressionDef),
}