lang: ast: Split off helpers into util file

lang/ast/structs.go

@@ -9981,56 +9981,3 @@ func (obj *ExprIf) Value() (types.Value, error) {
 	}
 	return obj.ElseBranch.Value()
 }
-
-// getScope pulls the local stored scope out of an Expr, without needing to add
-// a similarly named method to the Expr interface. This is private and not part
-// of the interface, because it is only used internally.
-// TODO: we could extend this to include Stmt's if it was ever useful
-func getScope(node interfaces.Expr) (*interfaces.Scope, error) {
-	//if _, ok := node.(interfaces.Expr); !ok {
-	//	return nil, fmt.Errorf("unexpected: %+v", node)
-	//}
-
-	switch expr := node.(type) {
-	case *ExprBool:
-		return expr.scope, nil
-	case *ExprStr:
-		return expr.scope, nil
-	case *ExprInt:
-		return expr.scope, nil
-	case *ExprFloat:
-		return expr.scope, nil
-	case *ExprList:
-		return expr.scope, nil
-	case *ExprMap:
-		return expr.scope, nil
-	case *ExprStruct:
-		return expr.scope, nil
-	case *ExprFunc:
-		return expr.scope, nil
-	case *ExprCall:
-		return expr.scope, nil
-	case *ExprVar:
-		return expr.scope, nil
-	case *ExprIf:
-		return expr.scope, nil
-
-	default:
-		return nil, fmt.Errorf("unexpected: %+v", node)
-	}
-}
-
-// trueCallee is a helper function because ExprTopLevel and ExprSingleton are
-// sometimes added around builtins. This makes it difficult for the type checker
-// to check if a particular builtin is the callee or not. This function removes
-// the ExprTopLevel and ExprSingleton wrappers, if they exist.
-func trueCallee(apparentCallee interfaces.Expr) interfaces.Expr {
-	switch x := apparentCallee.(type) {
-	case *ExprTopLevel:
-		return trueCallee(x.Definition)
-	case *ExprSingleton:
-		return trueCallee(x.Definition)
-	default:
-		return apparentCallee
-	}
-}