diff options
Diffstat (limited to 'dhall/src/binary.rs')
| -rw-r--r-- | dhall/src/binary.rs | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/dhall/src/binary.rs b/dhall/src/binary.rs new file mode 100644 index 0000000..0f09987 --- /dev/null +++ b/dhall/src/binary.rs @@ -0,0 +1,213 @@ +use dhall_core::*; +use itertools::*; +use serde_cbor::value::value as cbor; + +type ParsedExpr = Expr<X, Import>; + +#[derive(Debug)] +pub enum DecodeError { + CBORError(serde_cbor::error::Error), + WrongFormatError, +} + +pub fn decode(data: &[u8]) -> Result<ParsedExpr, DecodeError> { + match serde_cbor::de::from_slice(data) { + Ok(v) => cbor_value_to_dhall(&v), + Err(e) => Err(DecodeError::CBORError(e)), + } +} + +fn cbor_value_to_dhall(data: &cbor::Value) -> Result<ParsedExpr, DecodeError> { + use cbor::Value::*; + use dhall_core::{BinOp, Builtin, Const}; + use Expr::*; + match data { + String(s) => match Builtin::parse(s) { + Some(b) => Ok(Expr::Builtin(b)), + None => match s.as_str() { + "True" => Ok(Expr::BoolLit(true)), + "False" => Ok(Expr::BoolLit(false)), + "Type" => Ok(Expr::Const(Const::Type)), + "Kind" => Ok(Expr::Const(Const::Kind)), + s => Ok(Expr::Var(V(Label::from(s), 0))), + }, + }, + U64(n) => Ok(Expr::Var(V(Label::from("_"), *n as usize))), + F64(x) => Ok(DoubleLit(*x)), + Bool(b) => Ok(BoolLit(*b)), + Array(vec) => match vec.as_slice() { + [String(l), U64(n)] => { + let l = Label::from(l.as_str()); + Ok(Expr::Var(V(l, *n as usize))) + } + [U64(0), f, args..] => { + let f = cbor_value_to_dhall(&f)?; + let args = args + .iter() + .map(cbor_value_to_dhall) + .collect::<Result<Vec<_>, _>>()?; + Ok(args + .into_iter() + .fold(f, |acc, e| (Expr::App(bx(acc), bx(e))))) + } + [U64(1), x, y] => { + let x = bx(cbor_value_to_dhall(&x)?); + let y = bx(cbor_value_to_dhall(&y)?); + Ok(Lam(Label::from("_"), x, y)) + } + [U64(1), String(l), x, y] => { + let x = bx(cbor_value_to_dhall(&x)?); + let y = bx(cbor_value_to_dhall(&y)?); + let l = Label::from(l.as_str()); + Ok(Lam(l, x, y)) + } + [U64(2), x, y] => { + let x = bx(cbor_value_to_dhall(&x)?); + let y = bx(cbor_value_to_dhall(&y)?); + Ok(Pi(Label::from("_"), x, y)) + } + [U64(2), String(l), x, y] => { + let x = bx(cbor_value_to_dhall(&x)?); + let y = bx(cbor_value_to_dhall(&y)?); + let l = Label::from(l.as_str()); + Ok(Pi(l, x, y)) + } + [U64(3), U64(n), x, y] => { + let x = bx(cbor_value_to_dhall(&x)?); + let y = bx(cbor_value_to_dhall(&y)?); + use BinOp::*; + let op = match n { + 0 => BoolOr, + 1 => BoolAnd, + 2 => BoolEQ, + 3 => BoolNE, + 4 => NaturalPlus, + 5 => NaturalTimes, + 6 => TextAppend, + 7 => ListAppend, + 8 => Combine, + 9 => Prefer, + 10 => CombineTypes, + 11 => ImportAlt, + _ => Err(DecodeError::WrongFormatError)?, + }; + Ok(BinOp(op, x, y)) + } + [U64(4), t] => { + let t = bx(cbor_value_to_dhall(&t)?); + Ok(ListLit(Some(t), vec![])) + } + [U64(4), Null, rest..] => { + let rest = rest + .iter() + .map(cbor_value_to_dhall) + .collect::<Result<Vec<_>, _>>()?; + Ok(ListLit(None, rest)) + } + [U64(5), t] => { + let t = bx(cbor_value_to_dhall(&t)?); + Ok(OptionalLit(Some(t), vec![])) + } + [U64(5), Null, x] => { + let x = cbor_value_to_dhall(&x)?; + Ok(OptionalLit(None, vec![x])) + } + [U64(5), t, x] => { + let x = cbor_value_to_dhall(&x)?; + let t = bx(cbor_value_to_dhall(&t)?); + Ok(OptionalLit(Some(t), vec![x])) + } + [U64(6), x, y] => { + let x = bx(cbor_value_to_dhall(&x)?); + let y = bx(cbor_value_to_dhall(&y)?); + Ok(Merge(x, y, None)) + } + [U64(6), x, y, z] => { + let x = bx(cbor_value_to_dhall(&x)?); + let y = bx(cbor_value_to_dhall(&y)?); + let z = bx(cbor_value_to_dhall(&z)?); + Ok(Merge(x, y, Some(z))) + } + [U64(7), Object(map)] => { + let map = cbor_map_to_dhall_map(map)?; + Ok(Record(map)) + } + [U64(8), Object(map)] => { + let map = cbor_map_to_dhall_map(map)?; + Ok(RecordLit(map)) + } + [U64(9), x, String(l)] => { + let x = bx(cbor_value_to_dhall(&x)?); + let l = Label::from(l.as_str()); + Ok(Field(x, l)) + } + [U64(11), Object(map)] => { + let map = cbor_map_to_dhall_map(map)?; + Ok(Union(map)) + } + [U64(12), String(l), x, Object(map)] => { + let map = cbor_map_to_dhall_map(map)?; + let x = bx(cbor_value_to_dhall(&x)?); + let l = Label::from(l.as_str()); + Ok(UnionLit(l, x, map)) + } + [U64(14), x, y, z] => { + let x = bx(cbor_value_to_dhall(&x)?); + let y = bx(cbor_value_to_dhall(&y)?); + let z = bx(cbor_value_to_dhall(&z)?); + Ok(BoolIf(x, y, z)) + } + [U64(15), U64(x)] => Ok(NaturalLit(*x as Natural)), + [U64(16), U64(x)] => Ok(IntegerLit(*x as Integer)), + [U64(16), I64(x)] => Ok(IntegerLit(*x as Integer)), + [U64(18), String(first), _rest..] => { + // TODO: interpolated string + Ok(TextLit(first.clone())) + } + [U64(25), bindings..] => { + let mut tuples = bindings.iter().tuples(); + let bindings = (&mut tuples) + .map(|(x, t, v)| { + let x = match x { + String(s) => Label::from(s.as_str()), + _ => Err(DecodeError::WrongFormatError)?, + }; + let t = match t { + Null => None, + t => Some(bx(cbor_value_to_dhall(&t)?)), + }; + let v = bx(cbor_value_to_dhall(&v)?); + Ok((x, t, v)) + }) + .collect::<Result<Vec<_>, _>>()?; + let expr = tuples + .into_buffer() + .next() + .ok_or(DecodeError::WrongFormatError)?; + let expr = cbor_value_to_dhall(expr)?; + Ok(bindings + .into_iter() + .fold(expr, |acc, (x, t, v)| Let(x, t, v, bx(acc)))) + } + [U64(26), x, y] => { + let x = bx(cbor_value_to_dhall(&x)?); + let y = bx(cbor_value_to_dhall(&y)?); + Ok(Annot(x, y)) + } + _ => Err(DecodeError::WrongFormatError), + }, + _ => Err(DecodeError::WrongFormatError), + } +} + +fn cbor_map_to_dhall_map( + map: &std::collections::BTreeMap<cbor::ObjectKey, cbor::Value>, +) -> Result<std::collections::BTreeMap<Label, ParsedExpr>, DecodeError> { + map.iter() + .map(|(k, v)| -> Result<(_, _), _> { + let k = k.as_string().ok_or(DecodeError::WrongFormatError)?; + let v = cbor_value_to_dhall(v)?; + Ok((Label::from(k.as_ref()), v)) + }) + .collect::<Result<_, _>>() +} |