import GolangLean.PureEval

namespace GolangLean

/-! # Big-step operational semantics.

Mirror of octive-lean's `BigStep`. An inductive relation
`BigStepExpr : Env → Expr → Value → Env → Prop` that serves as the formal
specification of Go semantics, independent of the executable evaluator.

This is the layer where cross-language proof becomes possible: theorems
stated about `BigStepExpr` for Go should look identical in shape to the
Octave version. The shared shape is the candidate for a language-generic
core.

Stub. Constructors will be added one syntactic form at a time. -/

inductive BigStepExpr : Env → Expr → Value → Env → Prop where
  | placeholder : BigStepExpr env e v env  -- delete once real rules exist

end GolangLean