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use super::*;
#[derive(PartialEq, Clone)]
pub struct Promise {
pub(crate) robj: Robj,
}
impl Promise {
pub fn from_parts(code: Robj, environment: Environment) -> Result<Self> {
unsafe {
let sexp = Rf_allocSExp(PROMSXP);
let robj = Robj::from_sexp(sexp);
SET_PRCODE(sexp, code.get());
SET_PRENV(sexp, environment.robj.get());
SET_PRVALUE(sexp, R_UnboundValue);
Ok(Promise { robj })
}
}
pub fn code(&self) -> Robj {
unsafe {
let sexp = self.robj.get();
Robj::from_sexp(PRCODE(sexp))
}
}
pub fn environment(&self) -> Environment {
unsafe {
let sexp = self.robj.get();
Robj::from_sexp(PRENV(sexp)).try_into().unwrap()
}
}
pub fn value(&self) -> Robj {
unsafe {
let sexp = self.robj.get();
Robj::from_sexp(PRVALUE(sexp))
}
}
pub fn seen(&self) -> i32 {
unsafe {
let sexp = self.robj.get();
PRSEEN(sexp)
}
}
pub fn eval(&self) -> Result<Robj> {
assert!(self.is_promise());
if !self.value().is_unbound_value() {
Ok(self.value())
} else {
self.robj.eval()
}
}
}
impl std::fmt::Debug for Promise {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("Promise")
.field("code", &self.code())
.field("environment", &self.environment())
.finish()
}
}