diff options
Diffstat (limited to 'dhall/src/semantics/resolve/resolve.rs')
| -rw-r--r-- | dhall/src/semantics/resolve/resolve.rs | 332 |
1 files changed, 223 insertions, 109 deletions
diff --git a/dhall/src/semantics/resolve/resolve.rs b/dhall/src/semantics/resolve/resolve.rs index 16987de..116e1a5 100644 --- a/dhall/src/semantics/resolve/resolve.rs +++ b/dhall/src/semantics/resolve/resolve.rs @@ -15,7 +15,10 @@ use crate::syntax::{ Expr, ExprKind, FilePath, FilePrefix, Hash, ImportMode, ImportTarget, Span, UnspannedExpr, URL, }; -use crate::{Parsed, Resolved, Typed}; +use crate::{ + Ctxt, ImportAlternativeId, ImportId, ImportResultId, Parsed, Resolved, + Typed, +}; // TODO: evaluate import headers pub type Import = syntax::Import<()>; @@ -29,8 +32,10 @@ enum ImportLocationKind { Remote(Url), /// Environment variable Env(String), - /// Data without a location + /// Data without a location; chaining will start from current directory. Missing, + /// Token to signal that thi sfile should contain no imports. + NoImport, } /// The location of some data. @@ -101,6 +106,7 @@ impl ImportLocationKind { url = url.join(&path.file_path.join("/"))?; ImportLocationKind::Remote(url) } + ImportLocationKind::NoImport => unreachable!(), }) } @@ -120,6 +126,7 @@ impl ImportLocationKind { ImportLocationKind::Missing => { return Err(ImportError::Missing.into()) } + ImportLocationKind::NoImport => unreachable!(), }) } @@ -134,6 +141,7 @@ impl ImportLocationKind { ImportLocationKind::Missing => { return Err(ImportError::Missing.into()) } + ImportLocationKind::NoImport => unreachable!(), }) } @@ -149,6 +157,7 @@ impl ImportLocationKind { ("Environment", Some(name.clone())) } ImportLocationKind::Missing => ("Missing", None), + ImportLocationKind::NoImport => unreachable!(), }; let asloc_ty = make_aslocation_uniontype(); @@ -171,6 +180,12 @@ impl ImportLocation { mode: ImportMode::Code, } } + pub fn dhall_code_without_imports() -> Self { + ImportLocation { + kind: ImportLocationKind::NoImport, + mode: ImportMode::Code, + } + } pub fn local_dhall_code(path: PathBuf) -> Self { ImportLocation { kind: ImportLocationKind::Local(path), @@ -191,6 +206,10 @@ impl ImportLocation { fn chain(&self, import: &Import) -> Result<ImportLocation, Error> { // Makes no sense to chain an import if the current file is not a dhall file. assert!(matches!(self.mode, ImportMode::Code)); + if matches!(self.kind, ImportLocationKind::NoImport) { + Err(ImportError::UnexpectedImport(import.clone()))?; + } + let kind = match &import.location { ImportTarget::Local(prefix, path) => { self.kind.chain_local(*prefix, path)? @@ -227,30 +246,42 @@ impl ImportLocation { } /// Fetches the expression corresponding to this location. - fn fetch(&self, env: &mut ImportEnv, span: Span) -> Result<Typed, Error> { - let (hir, ty) = match self.mode { + fn fetch<'cx>( + &self, + env: &mut ImportEnv<'cx>, + span: Span, + ) -> Result<Typed<'cx>, Error> { + let cx = env.cx(); + let typed = match self.mode { ImportMode::Code => { let parsed = self.kind.fetch_dhall()?; - let typed = resolve_with_env(env, parsed)?.typecheck()?; - let hir = typed.normalize().to_hir(); - (hir, typed.ty) + let typed = parsed.resolve_with_env(env)?.typecheck(cx)?; + Typed { + // TODO: manage to keep the Nir around. Will need fixing variables. + hir: typed.normalize(cx).to_hir(), + ty: typed.ty, + } } ImportMode::RawText => { let text = self.kind.fetch_text()?; - let hir = Hir::new( - HirKind::Expr(ExprKind::TextLit(text.into())), - span, - ); - (hir, Type::from_builtin(Builtin::Text)) + Typed { + hir: Hir::new( + HirKind::Expr(ExprKind::TextLit(text.into())), + span, + ), + ty: Type::from_builtin(cx, Builtin::Text), + } } ImportMode::Location => { let expr = self.kind.to_location(); - let hir = skip_resolve_expr(&expr)?; - let ty = hir.typecheck_noenv()?.ty().clone(); - (hir, ty) + Parsed::from_expr_without_imports(expr) + .resolve(cx) + .unwrap() + .typecheck(cx) + .unwrap() } }; - Ok(Typed { hir, ty }) + Ok(typed) } } @@ -282,15 +313,21 @@ fn make_aslocation_uniontype() -> Expr { mkexpr(ExprKind::UnionType(union)) } -fn check_hash(import: &Import, typed: &Typed, span: Span) -> Result<(), Error> { +pub fn check_hash<'cx>( + cx: Ctxt<'cx>, + import: ImportId<'cx>, + result: ImportResultId<'cx>, +) -> Result<(), Error> { + let import = &cx[import]; if let (ImportMode::Code, Some(Hash::SHA256(hash))) = - (import.mode, &import.hash) + (import.import.mode, &import.import.hash) { - let actual_hash = typed.hir.to_expr_alpha().sha256_hash()?; + let expr = cx[result].hir.to_expr_alpha(cx); + let actual_hash = expr.sha256_hash()?; if hash[..] != actual_hash[..] { mkerr( ErrorBuilder::new("hash mismatch") - .span_err(span, "hash mismatch") + .span_err(import.span.clone(), "hash mismatch") .note(format!("Expected sha256:{}", hex::encode(hash))) .note(format!( "Found sha256:{}", @@ -332,127 +369,204 @@ fn desugar(expr: &Expr) -> Cow<'_, Expr> { } } -/// Traverse the expression, handling import alternatives and passing -/// found imports to the provided function. Also resolving names. -fn traverse_resolve_expr( +/// Fetch the import and store the result in the global context. +fn fetch_import<'cx>( + env: &mut ImportEnv<'cx>, + import_id: ImportId<'cx>, +) -> Result<ImportResultId<'cx>, Error> { + let cx = env.cx(); + let import = &cx[import_id].import; + let span = cx[import_id].span.clone(); + let location = cx[import_id].base_location.chain(import)?; + + // If the import is in the in-memory cache, or the hash is in the on-disk cache, return + // the cached contents. + if let Some(res_id) = env.get_from_mem_cache(&location) { + // The same location may be used with different or no hashes. Thus we need to check + // the hashes every time. + env.check_hash(import_id, res_id)?; + env.write_to_disk_cache(&import.hash, res_id); + return Ok(res_id); + } + if let Some(typed) = env.get_from_disk_cache(&import.hash) { + // No need to check the hash, it was checked before reading the file. + // We also don't write to the in-memory cache, because the location might be completely + // unrelated to the cached file (e.g. `missing sha256:...` is valid). + // This actually means that importing many times a same hashed import will take + // longer than importing many times a same non-hashed import. + let res_id = cx.push_import_result(typed); + return Ok(res_id); + } + + // Resolve this import, making sure that recursive imports don't cycle back to the + // current one. + let res = env.with_cycle_detection(location.clone(), |env| { + location.fetch(env, span.clone()) + }); + let typed = match res { + Ok(typed) => typed, + Err(e) => mkerr( + ErrorBuilder::new("error") + .span_err(span.clone(), e.to_string()) + .format(), + )?, + }; + + // Add the resolved import to the caches + let res_id = cx.push_import_result(typed); + env.check_hash(import_id, res_id)?; + env.write_to_disk_cache(&import.hash, res_id); + // Cache the mapping from this location to the result. + env.write_to_mem_cache(location, res_id); + + Ok(res_id) +} + +/// Part of a tree of imports. +#[derive(Debug, Clone, Copy)] +pub enum ImportNode<'cx> { + Import(ImportId<'cx>), + Alternative(ImportAlternativeId<'cx>), +} + +/// Traverse the expression and replace each import and import alternative by an id into the global +/// context. The ids are also accumulated into `nodes` so that we can resolve them afterwards. +fn traverse_accumulate<'cx>( + env: &mut ImportEnv<'cx>, name_env: &mut NameEnv, + nodes: &mut Vec<ImportNode<'cx>>, + base_location: &ImportLocation, expr: &Expr, - f: &mut impl FnMut(Import, Span) -> Result<Typed, Error>, -) -> Result<Hir, Error> { +) -> Hir<'cx> { + let cx = env.cx(); let expr = desugar(expr); - Ok(match expr.kind() { + let kind = match expr.kind() { ExprKind::Var(var) => match name_env.unlabel_var(&var) { - Some(v) => Hir::new(HirKind::Var(v), expr.span()), - None => mkerr( - ErrorBuilder::new(format!("unbound variable `{}`", var)) - .span_err(expr.span(), "not found in this scope") - .format(), - )?, + Some(v) => HirKind::Var(v), + None => HirKind::MissingVar(var.clone()), }, ExprKind::Op(OpKind::BinOp(BinOp::ImportAlt, l, r)) => { - match traverse_resolve_expr(name_env, l, f) { - Ok(l) => l, - Err(_) => { - match traverse_resolve_expr(name_env, r, f) { - Ok(r) => r, - // TODO: keep track of the other error too - Err(e) => return Err(e), - } - } - } + let mut imports_l = Vec::new(); + let l = traverse_accumulate( + env, + name_env, + &mut imports_l, + base_location, + l, + ); + let mut imports_r = Vec::new(); + let r = traverse_accumulate( + env, + name_env, + &mut imports_r, + base_location, + r, + ); + let alt = + cx.push_import_alternative(imports_l.into(), imports_r.into()); + nodes.push(ImportNode::Alternative(alt)); + HirKind::ImportAlternative(alt, l, r) } kind => { - let kind = kind.traverse_ref_maybe_binder(|l, e| { + let kind = kind.map_ref_maybe_binder(|l, e| { if let Some(l) = l { name_env.insert_mut(l); } - let hir = traverse_resolve_expr(name_env, e, f)?; + let hir = + traverse_accumulate(env, name_env, nodes, base_location, e); if l.is_some() { name_env.remove_mut(); } - Ok::<_, Error>(hir) - })?; - let kind = match kind { + hir + }); + match kind { ExprKind::Import(import) => { // TODO: evaluate import headers - let import = import.traverse_ref(|_| Ok::<_, Error>(()))?; - let imported = f(import, expr.span())?; - HirKind::Import(imported.hir, imported.ty) + let import = import.map_ref(|_| ()); + let import_id = cx.push_import( + base_location.clone(), + import, + expr.span(), + ); + nodes.push(ImportNode::Import(import_id)); + HirKind::Import(import_id) } kind => HirKind::Expr(kind), - }; - Hir::new(kind, expr.span()) + } } - }) + }; + Hir::new(kind, expr.span()) } -fn resolve_with_env( - env: &mut ImportEnv, +/// Take a list of nodes and recursively resolve them. +fn resolve_nodes<'cx>( + env: &mut ImportEnv<'cx>, + nodes: &[ImportNode<'cx>], +) -> Result<(), Error> { + for &node in nodes { + match node { + ImportNode::Import(import) => { + let res_id = fetch_import(env, import)?; + env.cx()[import].set_resultid(res_id); + } + ImportNode::Alternative(alt) => { + let alt = &env.cx()[alt]; + if resolve_nodes(env, &alt.left_imports).is_ok() { + alt.set_selected(true); + } else { + resolve_nodes(env, &alt.right_imports)?; + alt.set_selected(false); + } + } + } + } + Ok(()) +} + +fn resolve_with_env<'cx>( + env: &mut ImportEnv<'cx>, parsed: Parsed, -) -> Result<Resolved, Error> { +) -> Result<Resolved<'cx>, Error> { let Parsed(expr, base_location) = parsed; - let resolved = traverse_resolve_expr( + let mut nodes = Vec::new(); + // First we collect all imports. + let resolved = traverse_accumulate( + env, &mut NameEnv::new(), + &mut nodes, + &base_location, &expr, - &mut |import, span| { - let location = base_location.chain(&import)?; - - // If the import is in the in-memory cache, or the hash is in the on-disk cache, return - // the cached contents. - if let Some(typed) = env.get_from_mem_cache(&location) { - // The same location may be used with different or no hashes. Thus we need to check - // the hashes every time. - check_hash(&import, &typed, span)?; - env.write_to_disk_cache(&import.hash, &typed); - return Ok(typed); - } - if let Some(typed) = env.get_from_disk_cache(&import.hash) { - // No need to check the hash, it was checked before reading the file. We also don't - // write to the in-memory cache, because the location might be completely unrelated - // to the cached file (e.g. `missing sha256:...` is valid). - // This actually means that importing many times a same hashed import will take - // longer than importing many times a same non-hashed import. - return Ok(typed); - } - - // Resolve this import, making sure that recursive imports don't cycle back to the - // current one. - let res = env.with_cycle_detection(location.clone(), |env| { - location.fetch(env, span.clone()) - }); - let typed = match res { - Ok(typed) => typed, - Err(e) => mkerr( - ErrorBuilder::new("error") - .span_err(span.clone(), e.to_string()) - .format(), - )?, - }; - - // Add the resolved import to the caches - check_hash(&import, &typed, span)?; - env.write_to_disk_cache(&import.hash, &typed); - env.write_to_mem_cache(location, typed.clone()); - Ok(typed) - }, - )?; + ); + // Then we resolve them and choose sides for the alternatives. + resolve_nodes(env, &nodes)?; Ok(Resolved(resolved)) } -pub fn resolve(parsed: Parsed) -> Result<Resolved, Error> { - resolve_with_env(&mut ImportEnv::new(), parsed) +/// Resolves all imports and names. Returns errors if importing failed. Name errors are deferred to +/// typechecking. +pub fn resolve<'cx>( + cx: Ctxt<'cx>, + parsed: Parsed, +) -> Result<Resolved<'cx>, Error> { + parsed.resolve_with_env(&mut ImportEnv::new(cx)) } -pub fn skip_resolve_expr(expr: &Expr) -> Result<Hir, Error> { - traverse_resolve_expr(&mut NameEnv::new(), expr, &mut |import, _span| { - Err(ImportError::UnexpectedImport(import).into()) - }) +/// Resolves names, and errors if we find any imports. +pub fn skip_resolve<'cx>( + cx: Ctxt<'cx>, + parsed: Parsed, +) -> Result<Resolved<'cx>, Error> { + let parsed = Parsed::from_expr_without_imports(parsed.0); + Ok(resolve(cx, parsed)?) } -pub fn skip_resolve(parsed: Parsed) -> Result<Resolved, Error> { - let Parsed(expr, _) = parsed; - let resolved = skip_resolve_expr(&expr)?; - Ok(Resolved(resolved)) +impl Parsed { + fn resolve_with_env<'cx>( + self, + env: &mut ImportEnv<'cx>, + ) -> Result<Resolved<'cx>, Error> { + resolve_with_env(env, self) + } } pub trait Canonicalize { |