diff options
| -rw-r--r-- | tvix/eval/src/vm.rs | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/tvix/eval/src/vm.rs b/tvix/eval/src/vm.rs index e1f9d3096b89..52de99f490ed 100644 --- a/tvix/eval/src/vm.rs +++ b/tvix/eval/src/vm.rs @@ -38,11 +38,21 @@ impl CallFrame { } pub struct VM<'o> { + /// The VM call stack. One element is pushed onto this stack + /// each time a function is called or a thunk is forced. frames: Vec<CallFrame>, + + /// The VM value stack. This is actually a "stack of stacks", + /// with one stack-of-Values for each CallFrame in frames. This + /// is represented as a Vec<Value> rather than as + /// Vec<Vec<Value>> or a Vec<Value> inside CallFrame for + /// efficiency reasons: it avoids having to allocate a Vec on + /// the heap each time a CallFrame is entered. stack: Vec<Value>, - /// Stack indices of attribute sets from which variables should be - /// dynamically resolved (`with`). + /// Stack indices (absolute indexes into `stack`) of attribute + /// sets from which variables should be dynamically resolved + /// (`with`). with_stack: Vec<usize>, /// Runtime warnings collected during evaluation. |