use itertools::Itertools; use serde_cbor::value::value as cbor; use std::iter::FromIterator; use crate::error::DecodeError; use crate::syntax; use crate::syntax::{ Expr, ExprKind, FilePath, FilePrefix, Hash, ImportMode, ImportTarget, Integer, InterpolatedText, Label, Natural, NumKind, OpKind, Scheme, Span, UnspannedExpr, URL, V, }; type DecodedExpr = Expr; pub fn decode(data: &[u8]) -> Result { match serde_cbor::de::from_slice(data) { Ok(v) => cbor_value_to_dhall(&v), Err(e) => Err(DecodeError::CBORError(e)), } } // Should probably rename this fn rc(x: UnspannedExpr) -> Expr { Expr::new(x, Span::Decoded) } fn cbor_value_to_dhall(data: &cbor::Value) -> Result { use cbor::Value::*; use syntax::{BinOp, Builtin, Const}; use ExprKind::*; use OpKind::*; Ok(rc(match data { String(s) => match Builtin::parse(s) { Some(b) => ExprKind::Builtin(b), None => match s.as_str() { "True" => Num(NumKind::Bool(true)), "False" => Num(NumKind::Bool(false)), "Type" => Const(Const::Type), "Kind" => Const(Const::Kind), "Sort" => Const(Const::Sort), _ => { return Err(DecodeError::WrongFormatError( "builtin".to_owned(), )) } }, }, U64(n) => Var(V(Label::from("_"), *n as usize)), F64(x) => Num(NumKind::Double((*x).into())), Bool(b) => Num(NumKind::Bool(*b)), Array(vec) => match vec.as_slice() { [String(l), U64(n)] => { if l.as_str() == "_" { return Err(DecodeError::WrongFormatError( "`_` variable was encoded incorrectly".to_owned(), )); } let l = Label::from(l.as_str()); Var(V(l, *n as usize)) } [U64(0), f, args @ ..] => { if args.is_empty() { return Err(DecodeError::WrongFormatError( "Function application must have at least one argument" .to_owned(), )); } let mut f = cbor_value_to_dhall(&f)?; for a in args { let a = cbor_value_to_dhall(&a)?; f = rc(Op(App(f, a))) } return Ok(f); } [U64(1), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; Lam(Label::from("_"), x, y) } [U64(1), String(l), x, y] => { if l.as_str() == "_" { return Err(DecodeError::WrongFormatError( "`_` variable was encoded incorrectly".to_owned(), )); } let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; let l = Label::from(l.as_str()); Lam(l, x, y) } [U64(2), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; Pi(Label::from("_"), x, y) } [U64(2), String(l), x, y] => { if l.as_str() == "_" { return Err(DecodeError::WrongFormatError( "`_` variable was encoded incorrectly".to_owned(), )); } let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; let l = Label::from(l.as_str()); Pi(l, x, y) } [U64(3), U64(13), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; Op(Completion(x, y)) } [U64(3), U64(n), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = 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 => RecursiveRecordMerge, 9 => RightBiasedRecordMerge, 10 => RecursiveRecordTypeMerge, 11 => ImportAlt, 12 => Equivalence, _ => { return Err(DecodeError::WrongFormatError( "binop".to_owned(), )) } }; Op(BinOp(op, x, y)) } [U64(4), t] => { let t = cbor_value_to_dhall(&t)?; EmptyListLit(rc(Op(App( rc(ExprKind::Builtin(Builtin::List)), t, )))) } [U64(4), Null, rest @ ..] => { let rest = rest .iter() .map(cbor_value_to_dhall) .collect::, _>>()?; NEListLit(rest) } [U64(5), Null, x] => { let x = cbor_value_to_dhall(&x)?; SomeLit(x) } // Old-style optional literals [U64(5), t] => { let t = cbor_value_to_dhall(&t)?; Op(App(rc(ExprKind::Builtin(Builtin::OptionalNone)), t)) } [U64(5), t, x] => { let x = cbor_value_to_dhall(&x)?; let t = cbor_value_to_dhall(&t)?; Annot( rc(SomeLit(x)), rc(Op(App(rc(ExprKind::Builtin(Builtin::Optional)), t))), ) } [U64(6), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; Op(Merge(x, y, None)) } [U64(6), x, y, z] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; let z = cbor_value_to_dhall(&z)?; Op(Merge(x, y, Some(z))) } [U64(7), Object(map)] => { let map = cbor_map_to_dhall_map(map)?; RecordType(map) } [U64(8), Object(map)] => { let map = cbor_map_to_dhall_map(map)?; RecordLit(map) } [U64(9), x, String(l)] => { let x = cbor_value_to_dhall(&x)?; let l = Label::from(l.as_str()); Op(Field(x, l)) } [U64(10), x, Array(arr)] => { let x = cbor_value_to_dhall(&x)?; if let [y] = arr.as_slice() { let y = cbor_value_to_dhall(&y)?; Op(ProjectionByExpr(x, y)) } else { return Err(DecodeError::WrongFormatError( "projection-by-expr".to_owned(), )); } } [U64(10), x, rest @ ..] => { let x = cbor_value_to_dhall(&x)?; let labels = rest .iter() .map(|s| match s { String(s) => Ok(Label::from(s.as_str())), _ => Err(DecodeError::WrongFormatError( "projection".to_owned(), )), }) .collect::>()?; Op(Projection(x, labels)) } [U64(11), Object(map)] => { let map = cbor_map_to_dhall_opt_map(map)?; UnionType(map) } [U64(12), ..] => { return Err(DecodeError::WrongFormatError( "Union literals are not supported anymore".to_owned(), )) } [U64(14), x, y, z] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; let z = cbor_value_to_dhall(&z)?; Op(BoolIf(x, y, z)) } [U64(15), U64(x)] => Num(NumKind::Natural(*x as Natural)), [U64(16), U64(x)] => Num(NumKind::Integer(*x as Integer)), [U64(16), I64(x)] => Num(NumKind::Integer(*x as Integer)), [U64(18), String(first), rest @ ..] => { TextLit(InterpolatedText::from(( first.clone(), rest.iter() .tuples() .map(|(x, y)| { let x = cbor_value_to_dhall(&x)?; let y = match y { String(s) => s.clone(), _ => { return Err(DecodeError::WrongFormatError( "text".to_owned(), )) } }; Ok((x, y)) }) .collect::>()?, ))) } [U64(19), t] => { let t = cbor_value_to_dhall(&t)?; Assert(t) } [U64(24), hash, U64(mode), U64(scheme), rest @ ..] => { let mode = match mode { 0 => ImportMode::Code, 1 => ImportMode::RawText, 2 => ImportMode::Location, _ => { return Err(DecodeError::WrongFormatError(format!( "import/mode/unknown_mode: {:?}", mode ))) } }; let hash = match hash { Null => None, Bytes(bytes) => match bytes.as_slice() { [18, 32, rest @ ..] => { Some(Hash::SHA256(rest.to_vec())) } _ => { return Err(DecodeError::WrongFormatError(format!( "import/hash/unknown_multihash: {:?}", bytes ))) } }, _ => { return Err(DecodeError::WrongFormatError( "import/hash/should_be_bytes".to_owned(), )) } }; let mut rest = rest.iter(); let location = match scheme { 0 | 1 => { let scheme = match scheme { 0 => Scheme::HTTP, _ => Scheme::HTTPS, }; let headers = match rest.next() { Some(Null) => None, Some(x) => { let x = cbor_value_to_dhall(&x)?; Some(x) } _ => { return Err(DecodeError::WrongFormatError( "import/remote/headers".to_owned(), )) } }; let authority = match rest.next() { Some(String(s)) => s.to_owned(), _ => { return Err(DecodeError::WrongFormatError( "import/remote/authority".to_owned(), )) } }; let query = match rest.next_back() { Some(Null) => None, Some(String(s)) => Some(s.to_owned()), _ => { return Err(DecodeError::WrongFormatError( "import/remote/query".to_owned(), )) } }; let file_path = rest .map(|s| match s.as_string() { Some(s) => Ok(s.clone()), None => Err(DecodeError::WrongFormatError( "import/remote/path".to_owned(), )), }) .collect::>()?; let path = FilePath { file_path }; ImportTarget::Remote(URL { scheme, authority, path, query, headers, }) } 2 | 3 | 4 | 5 => { let prefix = match scheme { 2 => FilePrefix::Absolute, 3 => FilePrefix::Here, 4 => FilePrefix::Parent, 5 => FilePrefix::Home, _ => { return Err(DecodeError::WrongFormatError( "import/local/prefix".to_owned(), )) } }; let file_path = rest .map(|s| match s.as_string() { Some(s) => Ok(s.clone()), None => Err(DecodeError::WrongFormatError( "import/local/path".to_owned(), )), }) .collect::>()?; let path = FilePath { file_path }; ImportTarget::Local(prefix, path) } 6 => { let env = match rest.next() { Some(String(s)) => s.to_owned(), _ => { return Err(DecodeError::WrongFormatError( "import/env".to_owned(), )) } }; ImportTarget::Env(env) } 7 => ImportTarget::Missing, _ => { return Err(DecodeError::WrongFormatError( "import/type".to_owned(), )) } }; Import(syntax::Import { mode, hash, location, }) } [U64(25), bindings @ ..] => { let mut tuples = bindings.iter().tuples(); let bindings = (&mut tuples) .map(|(x, t, v)| { let x = x.as_string().ok_or_else(|| { DecodeError::WrongFormatError( "let/label".to_owned(), ) })?; let x = Label::from(x.as_str()); let t = match t { Null => None, t => Some(cbor_value_to_dhall(&t)?), }; let v = cbor_value_to_dhall(&v)?; Ok((x, t, v)) }) .collect::, _>>()?; let expr = tuples.into_buffer().next().ok_or_else(|| { DecodeError::WrongFormatError("let/expr".to_owned()) })?; let expr = cbor_value_to_dhall(expr)?; return Ok(bindings .into_iter() .rev() .fold(expr, |acc, (x, t, v)| rc(Let(x, t, v, acc)))); } [U64(26), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; Annot(x, y) } [U64(27), x] => { let x = cbor_value_to_dhall(&x)?; Op(ToMap(x, None)) } [U64(27), x, y] => { let x = cbor_value_to_dhall(&x)?; let y = cbor_value_to_dhall(&y)?; Op(ToMap(x, Some(y))) } [U64(28), x] => { let x = cbor_value_to_dhall(&x)?; EmptyListLit(x) } _ => { return Err(DecodeError::WrongFormatError(format!( "{:?}", data ))) } }, _ => return Err(DecodeError::WrongFormatError(format!("{:?}", data))), })) } fn cbor_map_to_dhall_map<'a, T>( map: impl IntoIterator, ) -> Result where T: FromIterator<(Label, DecodedExpr)>, { map.into_iter() .map(|(k, v)| -> Result<(_, _), _> { let k = k.as_string().ok_or_else(|| { DecodeError::WrongFormatError("map/key".to_owned()) })?; let v = cbor_value_to_dhall(v)?; Ok((Label::from(k.as_ref()), v)) }) .collect::>() } fn cbor_map_to_dhall_opt_map<'a, T>( map: impl IntoIterator, ) -> Result where T: FromIterator<(Label, Option)>, { map.into_iter() .map(|(k, v)| -> Result<(_, _), _> { let k = k.as_string().ok_or_else(|| { DecodeError::WrongFormatError("map/key".to_owned()) })?; let v = match v { cbor::Value::Null => None, _ => Some(cbor_value_to_dhall(v)?), }; Ok((Label::from(k.as_ref()), v)) }) .collect::>() }