diff options
Diffstat (limited to 'tvix/eval/src/compiler.rs')
| -rw-r--r-- | tvix/eval/src/compiler.rs | 50 |
1 files changed, 45 insertions, 5 deletions
diff --git a/tvix/eval/src/compiler.rs b/tvix/eval/src/compiler.rs index 1d63acbb0ab4..3b33961d26d9 100644 --- a/tvix/eval/src/compiler.rs +++ b/tvix/eval/src/compiler.rs @@ -9,8 +9,8 @@ //! //! However, at the time that the AST is passed to the compiler we //! have verified that `rnix` considers the code to be correct, so all -//! variants are filed. In cases where the invariant is guaranteed by -//! the code in this module, `debug_assert!` has been used to catch +//! variants are fulfilled. In cases where the invariant is guaranteed +//! by the code in this module, `debug_assert!` has been used to catch //! mistakes early during development. use path_clean::PathClean; @@ -69,6 +69,16 @@ struct Scope { // Stack indices of attribute sets currently in scope through // `with`. with_stack: Vec<With>, + + // Certain symbols are considered to be "poisoning" the scope when + // defined. This is because users are allowed to override symbols + // like 'true' or 'null'. + // + // To support this efficiently, the depth at which a poisoning + // occured is tracked here. + poisoned_true: usize, + poisoned_false: usize, + poisoned_null: usize, } struct Compiler { @@ -343,9 +353,9 @@ impl Compiler { // optimised information about any "weird" stuff that's // happened to the scope (such as overrides of these // literals, or builtins). - "true" => self.chunk.push_op(OpCode::OpTrue), - "false" => self.chunk.push_op(OpCode::OpFalse), - "null" => self.chunk.push_op(OpCode::OpNull), + "true" if self.scope.poisoned_true == 0 => self.chunk.push_op(OpCode::OpTrue), + "false" if self.scope.poisoned_false == 0 => self.chunk.push_op(OpCode::OpFalse), + "null" if self.scope.poisoned_null == 0 => self.chunk.push_op(OpCode::OpNull), name => { // Note: `with` and some other special scoping @@ -817,6 +827,19 @@ impl Compiler { fn end_scope(&mut self) { let mut scope = &mut self.scope; debug_assert!(scope.scope_depth != 0, "can not end top scope"); + + // If this scope poisoned any builtins or special identifiers, + // they need to be reset. + if scope.poisoned_true == scope.scope_depth { + scope.poisoned_true = 0; + } + if scope.poisoned_false == scope.scope_depth { + scope.poisoned_false = 0; + } + if scope.poisoned_null == scope.scope_depth { + scope.poisoned_null = 0; + } + scope.scope_depth -= 1; // When ending a scope, all corresponding locals need to be @@ -846,6 +869,23 @@ impl Compiler { } fn push_local<S: Into<String>>(&mut self, name: S) { + // Set up scope poisoning if required. + let name = name.into(); + match name.as_str() { + "true" if self.scope.poisoned_true == 0 => { + self.scope.poisoned_true = self.scope.scope_depth + } + + "false" if self.scope.poisoned_false == 0 => { + self.scope.poisoned_false = self.scope.scope_depth + } + + "null" if self.scope.poisoned_null == 0 => { + self.scope.poisoned_null = self.scope.scope_depth + } + + _ => {} + }; self.scope.locals.push(Local { name: name.into(), depth: self.scope.scope_depth, |