Move input/output type from Command to Signature (#5880)

crates/nu-command/src/database/commands/alias.rs

@@ -19,6 +19,8 @@ impl Command for AliasDb {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("alias", SyntaxShape::String, "alias name")
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -82,14 +84,6 @@ impl Command for AliasDb {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn search_terms(&self) -> Vec<&str> {
         vec!["database", "alias", "column"]
     }

crates/nu-command/src/database/commands/and.rs

@@ -25,6 +25,8 @@ impl Command for AndDb {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("where", SyntaxShape::Any, "Where expression on the table")
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -32,14 +34,6 @@ impl Command for AndDb {
         vec!["database", "where"]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![
             Example {

crates/nu-command/src/database/commands/collect.rs

@@ -15,21 +15,16 @@ impl Command for CollectDb {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("database".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Any)
+            .category(Category::Custom("database".into()))
     }
 
     fn usage(&self) -> &str {
         "Collects a query from a database database connection"
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Any
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![Example {
             description: "Collect from a select query",

crates/nu-command/src/database/commands/describe.rs

@@ -15,21 +15,16 @@ impl Command for DescribeDb {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("database".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Any)
+            .category(Category::Custom("database".into()))
     }
 
     fn usage(&self) -> &str {
         "Describes connection and query of the DB object"
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Any
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![Example {
             description: "Describe SQLite database constructed query",

crates/nu-command/src/database/commands/from.rs

@@ -35,6 +35,8 @@ impl Command for FromDb {
                 "Alias for the selected table",
                 Some('a'),
             )
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -42,14 +44,6 @@ impl Command for FromDb {
         vec!["database", "from"]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![Example {
             description: "Selects a table from database",

crates/nu-command/src/database/commands/group_by.rs

@@ -29,6 +29,8 @@ impl Command for GroupByDb {
                 SyntaxShape::Any,
                 "Select expression(s) on the table",
             )
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -36,14 +38,6 @@ impl Command for GroupByDb {
         vec!["database", "select"]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![
             Example {

crates/nu-command/src/database/commands/join.rs

@@ -41,6 +41,8 @@ impl Command for JoinDb {
             .switch("right", "right outer join", Some('r'))
             .switch("outer", "full outer join", Some('o'))
             .switch("cross", "cross join", Some('c'))
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -48,14 +50,6 @@ impl Command for JoinDb {
         vec!["database", "join"]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![
             Example {

crates/nu-command/src/database/commands/limit.rs

@@ -28,6 +28,8 @@ impl Command for LimitDb {
                 SyntaxShape::Int,
                 "Number of rows to extract for query",
             )
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -61,14 +63,6 @@ impl Command for LimitDb {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/database/commands/open.rs

@@ -19,6 +19,8 @@ impl Command for OpenDb {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("query", SyntaxShape::Filepath, "SQLite file to be opened")
+            .input_type(Type::Any)
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -38,14 +40,6 @@ impl Command for OpenDb {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/database/commands/or.rs

@@ -25,6 +25,8 @@ impl Command for OrDb {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("where", SyntaxShape::Any, "Where expression on the table")
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -32,14 +34,6 @@ impl Command for OrDb {
         vec!["database", "where"]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![
             Example {

crates/nu-command/src/database/commands/order_by.rs

@@ -31,6 +31,8 @@ impl Command for OrderByDb {
                 SyntaxShape::Any,
                 "Select expression(s) on the table",
             )
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -38,14 +40,6 @@ impl Command for OrderByDb {
         vec!["database", "order-by"]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![
             Example {

crates/nu-command/src/database/commands/query.rs

@@ -23,6 +23,8 @@ impl Command for QueryDb {
                 SyntaxShape::String,
                 "SQL to execute against the database",
             )
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Any)
             .category(Category::Custom("database".into()))
     }
 
@@ -30,14 +32,6 @@ impl Command for QueryDb {
         "Query a database using SQL."
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Any
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![Example {
             description: "Execute a query statement using the database connection",

crates/nu-command/src/database/commands/schema.rs

@@ -15,21 +15,16 @@ impl Command for SchemaDb {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("database".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Any)
+            .category(Category::Custom("database".into()))
     }
 
     fn usage(&self) -> &str {
         "Show sqlite database information, including its schema."
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Any
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![Example {
             description: "Show the schema of a SQLite database",

crates/nu-command/src/database/commands/select.rs

@@ -27,6 +27,8 @@ impl Command for ProjectionDb {
                 SyntaxShape::Any,
                 "Select expression(s) on the table",
             )
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -34,14 +36,6 @@ impl Command for ProjectionDb {
         vec!["database", "select"]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![
             Example {

crates/nu-command/src/database/commands/to_db.rs

@@ -19,7 +19,10 @@ impl Command for ToDataBase {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("database".into()))
+        Signature::build(self.name())
+            .input_type(Type::Any)
+            .output_type(Type::Custom("database".into()))
+            .category(Category::Custom("database".into()))
     }
 
     fn search_terms(&self) -> Vec<&str> {
@@ -34,14 +37,6 @@ impl Command for ToDataBase {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn run(
         &self,
         _engine_state: &EngineState,

crates/nu-command/src/database/commands/where_.rs

@@ -25,6 +25,8 @@ impl Command for WhereDb {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("where", SyntaxShape::Any, "Where expression on the table")
+            .input_type(Type::Custom("database".into()))
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -32,14 +34,6 @@ impl Command for WhereDb {
         vec!["database", "where"]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![Example {
             description: "selects a column from a database with a where clause",

crates/nu-command/src/database/expressions/alias.rs

@@ -19,6 +19,8 @@ impl Command for AliasExpr {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("alias", SyntaxShape::String, "alias name")
+            .input_type(Type::Custom("db-expression".into()))
+            .output_type(Type::Custom("db-expression".into()))
             .category(Category::Custom("db-expression".into()))
     }
 
@@ -67,14 +69,6 @@ impl Command for AliasExpr {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
     fn search_terms(&self) -> Vec<&str> {
         vec!["database", "alias", "column"]
     }

crates/nu-command/src/database/expressions/and.rs

@@ -24,6 +24,8 @@ impl Command for AndExpr {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("and", SyntaxShape::Any, "AND expression")
+            .input_type(Type::Custom("db-expression".into()))
+            .output_type(Type::Custom("db-expression".into()))
             .category(Category::Custom("db-expression".into()))
     }
 
@@ -31,14 +33,6 @@ impl Command for AndExpr {
         vec!["database", "and", "expression"]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![Example {
             description: "Creates an AND expression",

crates/nu-command/src/database/expressions/as_nu.rs

@@ -19,7 +19,10 @@ impl Command for ExprAsNu {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("db-expression".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("db-expression".into()))
+            .output_type(Type::Any)
+            .category(Category::Custom("db-expression".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -43,14 +46,6 @@ impl Command for ExprAsNu {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Any
-    }
-
     fn run(
         &self,
         _engine_state: &EngineState,

crates/nu-command/src/database/expressions/field.rs

@@ -18,6 +18,8 @@ impl Command for FieldExpr {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("name", SyntaxShape::String, "column name")
+            .input_type(Type::Any)
+            .output_type(Type::Custom("db-expression".into()))
             .category(Category::Custom("db-expression".into()))
     }
 
@@ -50,14 +52,6 @@ impl Command for FieldExpr {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/database/expressions/function.rs

@@ -21,6 +21,8 @@ impl Command for FunctionExpr {
             .required("name", SyntaxShape::String, "function name")
             .switch("distinct", "distict values", Some('d'))
             .rest("arguments", SyntaxShape::Any, "function arguments")
+            .input_type(Type::Any)
+            .output_type(Type::Custom("db-expression".into()))
             .category(Category::Custom("db-expression".into()))
     }
 
@@ -89,14 +91,6 @@ impl Command for FunctionExpr {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
     fn search_terms(&self) -> Vec<&str> {
         vec!["database", "function", "expression"]
     }

crates/nu-command/src/database/expressions/or.rs

@@ -24,6 +24,8 @@ impl Command for OrExpr {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("or", SyntaxShape::Any, "OR expression")
+            .input_type(Type::Custom("db-expression".into()))
+            .output_type(Type::Custom("db-expression".into()))
             .category(Category::Custom("db-expression".into()))
     }
 
@@ -31,14 +33,6 @@ impl Command for OrExpr {
         vec!["database", "or", "expression"]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
     fn examples(&self) -> Vec<Example> {
         vec![Example {
             description: "Creates an AND expression",

crates/nu-command/src/database/expressions/over.rs

@@ -23,6 +23,8 @@ impl Command for OverExpr {
                 SyntaxShape::Any,
                 "columns to partition the window function",
             )
+            .input_type(Type::Custom("db-expression".into()))
+            .output_type(Type::Custom("db-expression".into()))
             .category(Category::Custom("db-expression".into()))
     }
 
@@ -90,14 +92,6 @@ impl Command for OverExpr {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("db-expression".into())
-    }
-
     fn search_terms(&self) -> Vec<&str> {
         vec!["database", "over", "expression"]
     }

crates/nu-command/src/database/test_database.rs

@@ -29,6 +29,8 @@ impl Command for CustomOpen {
                 nu_protocol::SyntaxShape::String,
                 "the filename to use",
             )
+            .input_type(Type::Any)
+            .output_type(Type::Custom("database".into()))
             .category(Category::Custom("database".into()))
     }
 
@@ -45,14 +47,6 @@ impl Command for CustomOpen {
         let db = SQLiteDatabase::new(path);
         Ok(db.into_value(call.head).into_pipeline_data())
     }
-
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("database".into())
-    }
 }
 
 pub fn test_database(cmds: Vec<Box<dyn Command + 'static>>) {

crates/nu-command/src/dataframe/eager/append.rs

@@ -23,6 +23,8 @@ impl Command for AppendDF {
         Signature::build(self.name())
             .required("other", SyntaxShape::Any, "dataframe to be appended")
             .switch("col", "appends in col orientation", Some('c'))
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -87,14 +89,6 @@ impl Command for AppendDF {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/describe.rs

@@ -29,6 +29,8 @@ impl Command for DescribeDF {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .category(Category::Custom("dataframe".into()))
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .named(
                 "quantiles",
                 SyntaxShape::Table,
@@ -95,14 +97,6 @@ impl Command for DescribeDF {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/drop.rs

@@ -23,6 +23,8 @@ impl Command for DropDF {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .rest("rest", SyntaxShape::Any, "column names to be dropped")
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -41,14 +43,6 @@ impl Command for DropDF {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/drop_duplicates.rs

@@ -34,6 +34,8 @@ impl Command for DropDuplicates {
                 "keeps last duplicate value (by default keeps first)",
                 Some('l'),
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -58,14 +60,6 @@ impl Command for DropDuplicates {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/drop_nulls.rs

@@ -27,6 +27,8 @@ impl Command for DropNulls {
                 SyntaxShape::Table,
                 "subset of columns to drop nulls",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -78,14 +80,6 @@ impl Command for DropNulls {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/dtypes.rs

@@ -18,7 +18,10 @@ impl Command for DataTypes {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -42,14 +45,6 @@ impl Command for DataTypes {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/dummies.rs

@@ -19,7 +19,10 @@ impl Command for Dummies {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -93,14 +96,6 @@ impl Command for Dummies {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/filter_with.rs

@@ -29,6 +29,8 @@ impl Command for FilterWith {
                 SyntaxShape::Any,
                 "boolean mask used to filter data",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe or lazyframe".into()))
     }
 
@@ -62,14 +64,6 @@ impl Command for FilterWith {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/first.rs

@@ -21,6 +21,8 @@ impl Command for FirstDF {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .optional("rows", SyntaxShape::Int, "Number of rows for head")
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -39,14 +41,6 @@ impl Command for FirstDF {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/get.rs

@@ -24,6 +24,8 @@ impl Command for GetDF {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .rest("rest", SyntaxShape::Any, "column names to sort dataframe")
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -42,14 +44,6 @@ impl Command for GetDF {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/last.rs

@@ -21,6 +21,8 @@ impl Command for LastDF {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .optional("rows", SyntaxShape::Int, "Number of rows for tail")
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -39,14 +41,6 @@ impl Command for LastDF {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/melt.rs

@@ -48,6 +48,8 @@ impl Command for MeltDF {
                 "optional name for value column",
                 Some('l'),
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -109,14 +111,6 @@ impl Command for MeltDF {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/open.rs

@@ -58,6 +58,8 @@ impl Command for OpenDataFrame {
                 "Columns to be selected from csv file. CSV and Parquet file",
                 None,
             )
+            .input_type(Type::Any)
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -69,14 +71,6 @@ impl Command for OpenDataFrame {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/rename.rs

@@ -33,6 +33,8 @@ impl Command for RenameDF {
                 SyntaxShape::Any,
                 "New names for the selected column(s). A string or list of strings",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe or lazyframe".into()))
     }
 
@@ -94,14 +96,6 @@ impl Command for RenameDF {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/sample.rs

@@ -41,6 +41,8 @@ impl Command for SampleDF {
             )
             .switch("replace", "sample with replace", Some('e'))
             .switch("shuffle", "shuffle sample", Some('u'))
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -59,14 +61,6 @@ impl Command for SampleDF {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/shape.rs

@@ -21,7 +21,10 @@ impl Command for ShapeDF {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -39,14 +42,6 @@ impl Command for ShapeDF {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/slice.rs

@@ -25,6 +25,8 @@ impl Command for SliceDF {
         Signature::build(self.name())
             .required("offset", SyntaxShape::Int, "start of slice")
             .required("size", SyntaxShape::Int, "size of slice")
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -43,14 +45,6 @@ impl Command for SliceDF {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/take.rs

@@ -29,6 +29,8 @@ impl Command for TakeDF {
                 SyntaxShape::Any,
                 "list of indices used to take data",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -71,14 +73,6 @@ impl Command for TakeDF {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/to_csv.rs

@@ -32,6 +32,8 @@ impl Command for ToCSV {
                 Some('d'),
             )
             .switch("no-header", "Indicates if file doesn't have header", None)
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Any)
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -50,14 +52,6 @@ impl Command for ToCSV {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Any
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/to_df.rs

@@ -19,7 +19,10 @@ impl Command for ToDataFrame {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Any)
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -103,14 +106,6 @@ impl Command for ToDataFrame {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         _engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/to_nu.rs

@@ -28,6 +28,8 @@ impl Command for ToNu {
                 Some('n'),
             )
             .switch("tail", "shows tail rows", Some('t'))
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Any)
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -64,14 +66,6 @@ impl Command for ToNu {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Any
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/to_parquet.rs

@@ -25,6 +25,8 @@ impl Command for ToParquet {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("file", SyntaxShape::Filepath, "file path to save dataframe")
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Any)
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -36,14 +38,6 @@ impl Command for ToParquet {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Any
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/eager/with_column.rs

@@ -27,6 +27,8 @@ impl Command for WithColumn {
                 SyntaxShape::Any,
                 "series to be added or expressions used to define the new columns",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe or lazyframe".into()))
     }
 
@@ -91,14 +93,6 @@ impl Command for WithColumn {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/expressions/alias.rs

@@ -26,6 +26,8 @@ impl Command for ExprAlias {
                 SyntaxShape::String,
                 "Alias name for the expression",
             )
+            .input_type(Type::Custom("expression".into()))
+            .output_type(Type::Custom("expression".into()))
             .category(Category::Custom("expression".into()))
     }
 
@@ -57,14 +59,6 @@ impl Command for ExprAlias {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("expression".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("expression".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/expressions/as_nu.rs

@@ -19,7 +19,10 @@ impl Command for ExprAsNu {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("expression".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("expression".into()))
+            .output_type(Type::Any)
+            .category(Category::Custom("expression".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -43,14 +46,6 @@ impl Command for ExprAsNu {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("expression".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Any
-    }
-
     fn run(
         &self,
         _engine_state: &EngineState,

crates/nu-command/src/dataframe/expressions/col.rs

@@ -26,6 +26,8 @@ impl Command for ExprCol {
                 SyntaxShape::String,
                 "Name of column to be used",
             )
+            .input_type(Type::Any)
+            .output_type(Type::Custom("expression".into()))
             .category(Category::Custom("expression".into()))
     }
 
@@ -50,14 +52,6 @@ impl Command for ExprCol {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("expression".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/expressions/expressions_macro.rs

@@ -25,21 +25,16 @@ macro_rules! expr_command {
             }
 
             fn signature(&self) -> Signature {
-                Signature::build(self.name()).category(Category::Custom("expression".into()))
+                Signature::build(self.name())
+                    .input_type(Type::Custom("expression".into()))
+                    .output_type(Type::Custom("expression".into()))
+                    .category(Category::Custom("expression".into()))
             }
 
             fn examples(&self) -> Vec<Example> {
                 $examples
             }
 
-            fn input_type(&self) -> Type {
-                Type::Custom("expression".into())
-            }
-
-            fn output_type(&self) -> Type {
-                Type::Custom("expression".into())
-            }
-
             fn run(
                 &self,
                 _engine_state: &EngineState,

crates/nu-command/src/dataframe/expressions/lit.rs

@@ -25,6 +25,8 @@ impl Command for ExprLit {
                 SyntaxShape::Any,
                 "literal to construct the expression",
             )
+            .input_type(Type::Any)
+            .output_type(Type::Custom("expression".into()))
             .category(Category::Custom("expression".into()))
     }
 
@@ -49,14 +51,6 @@ impl Command for ExprLit {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("expression".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/expressions/otherwise.rs

@@ -25,6 +25,8 @@ impl Command for ExprOtherwise {
                 SyntaxShape::Any,
                 "expressioini to apply when no when predicate matches",
             )
+            .input_type(Type::Any)
+            .output_type(Type::Custom("expression".into()))
             .category(Category::Custom("expression".into()))
     }
 
@@ -77,14 +79,6 @@ impl Command for ExprOtherwise {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("expression".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/expressions/quantile.rs

@@ -26,6 +26,8 @@ impl Command for ExprQuantile {
                 SyntaxShape::Number,
                 "quantile value for quantile operation",
             )
+            .input_type(Type::Custom("expression".into()))
+            .output_type(Type::Custom("expression".into()))
             .category(Category::Custom("expression".into()))
     }
 
@@ -53,14 +55,6 @@ impl Command for ExprQuantile {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("expression".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("expression".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/expressions/when.rs

@@ -31,6 +31,8 @@ impl Command for ExprWhen {
                 SyntaxShape::Any,
                 "expression that will be applied when predicate is true",
             )
+            .input_type(Type::Custom("expression".into()))
+            .output_type(Type::Custom("expression".into()))
             .category(Category::Custom("expression".into()))
     }
 
@@ -83,14 +85,6 @@ impl Command for ExprWhen {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("expression".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("expression".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/aggregate.rs

@@ -26,6 +26,8 @@ impl Command for LazyAggregate {
                 SyntaxShape::Any,
                 "Expression(s) that define the aggregations to be applied",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("lazyframe".into()))
     }
 
@@ -101,14 +103,6 @@ impl Command for LazyAggregate {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/collect.rs

@@ -20,7 +20,10 @@ impl Command for LazyCollect {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("lazyframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("lazyframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -44,14 +47,6 @@ impl Command for LazyCollect {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         _engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/fetch.rs

@@ -26,6 +26,8 @@ impl Command for LazyFetch {
                 SyntaxShape::Int,
                 "number of rows to be fetched from lazyframe",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("lazyframe".into()))
     }
 
@@ -50,14 +52,6 @@ impl Command for LazyFetch {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/fill_na.rs

@@ -25,6 +25,8 @@ impl Command for LazyFillNA {
                 SyntaxShape::Any,
                 "Expression to use to fill the NAN values",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("lazyframe".into()))
     }
 
@@ -36,14 +38,6 @@ impl Command for LazyFillNA {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/fill_null.rs

@@ -25,6 +25,8 @@ impl Command for LazyFillNull {
                 SyntaxShape::Any,
                 "Expression to use to fill the null values",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("lazyframe".into()))
     }
 
@@ -49,14 +51,6 @@ impl Command for LazyFillNull {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/groupby.rs

@@ -26,6 +26,8 @@ impl Command for ToLazyGroupBy {
                 SyntaxShape::Any,
                 "Expression(s) that define the lazy group by",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("lazyframe".into()))
     }
 
@@ -101,14 +103,6 @@ impl Command for ToLazyGroupBy {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/join.rs

@@ -38,6 +38,8 @@ impl Command for LazyJoin {
                 "Suffix to use on columns with same name",
                 Some('s'),
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("lazyframe".into()))
     }
 
@@ -160,14 +162,6 @@ impl Command for LazyJoin {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/macro_commands.rs

@@ -23,21 +23,16 @@ macro_rules! lazy_command {
             }
 
             fn signature(&self) -> Signature {
-                Signature::build(self.name()).category(Category::Custom("lazyframe".into()))
+                Signature::build(self.name())
+                    .input_type(Type::Custom("dataframe".into()))
+                    .output_type(Type::Custom("dataframe".into()))
+                    .category(Category::Custom("lazyframe".into()))
             }
 
             fn examples(&self) -> Vec<Example> {
                 $examples
             }
 
-            fn input_type(&self) -> Type {
-                Type::Custom("dataframe".into())
-            }
-
-            fn output_type(&self) -> Type {
-                Type::Custom("dataframe".into())
-            }
-
             fn run(
                 &self,
                 _engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/quantile.rs

@@ -26,6 +26,8 @@ impl Command for LazyQuantile {
                 SyntaxShape::Number,
                 "quantile value for quantile operation",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("lazyframe".into()))
     }
 
@@ -44,14 +46,6 @@ impl Command for LazyQuantile {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/select.rs

@@ -27,6 +27,8 @@ impl Command for LazySelect {
                 SyntaxShape::Any,
                 "Expression(s) that define the column selection",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("lazyframe".into()))
     }
 
@@ -45,14 +47,6 @@ impl Command for LazySelect {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/sort_by_expr.rs

@@ -32,6 +32,8 @@ impl Command for LazySortBy {
                 "Reverse sorting. Default is false",
                 Some('r'),
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("lazyframe".into()))
     }
 
@@ -87,14 +89,6 @@ impl Command for LazySortBy {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/lazy/to_lazy.rs

@@ -19,7 +19,10 @@ impl Command for ToLazyFrame {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("lazyframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Any)
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("lazyframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -30,14 +33,6 @@ impl Command for ToLazyFrame {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         _engine_state: &EngineState,

crates/nu-command/src/dataframe/series/all_false.rs

@@ -19,7 +19,10 @@ impl Command for AllFalse {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -53,14 +56,6 @@ impl Command for AllFalse {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/all_true.rs

@@ -19,7 +19,10 @@ impl Command for AllTrue {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -53,14 +56,6 @@ impl Command for AllTrue {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/arg_max.rs

@@ -20,7 +20,10 @@ impl Command for ArgMax {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -38,14 +41,6 @@ impl Command for ArgMax {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/arg_min.rs

@@ -20,7 +20,10 @@ impl Command for ArgMin {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -38,14 +41,6 @@ impl Command for ArgMin {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/cumulative.rs

@@ -56,6 +56,8 @@ impl Command for Cumulative {
         Signature::build(self.name())
             .required("type", SyntaxShape::String, "rolling operation")
             .switch("reverse", "Reverse cumulative calculation", Some('r'))
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -80,14 +82,6 @@ impl Command for Cumulative {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/as_date.rs

@@ -31,7 +31,9 @@ impl Command for AsDate {
         Signature::build(self.name())
             .required("format", SyntaxShape::String, "formatting date string")
             .switch("not-exact", "the format string may be contained in the date (e.g. foo-2021-01-01-bar could match 2021-01-01)", Some('n'))
-            .category(Category::Custom("dataframe".into()))
+                        .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+.category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -42,14 +44,6 @@ impl Command for AsDate {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/as_datetime.rs

@@ -40,7 +40,9 @@ impl Command for AsDateTime {
         Signature::build(self.name())
             .required("format", SyntaxShape::String, "formatting date time string")
             .switch("not-exact", "the format string may be contained in the date (e.g. foo-2021-01-01-bar could match 2021-01-01)", Some('n'))
-            .category(Category::Custom("dataframe".into()))
+                        .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+.category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -75,14 +77,6 @@ impl Command for AsDateTime {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/get_day.rs

@@ -20,7 +20,10 @@ impl Command for GetDay {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -40,14 +43,6 @@ impl Command for GetDay {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/get_hour.rs

@@ -20,7 +20,10 @@ impl Command for GetHour {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -40,14 +43,6 @@ impl Command for GetHour {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/get_minute.rs

@@ -20,7 +20,10 @@ impl Command for GetMinute {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -40,14 +43,6 @@ impl Command for GetMinute {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/get_month.rs

@@ -20,7 +20,10 @@ impl Command for GetMonth {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -40,14 +43,6 @@ impl Command for GetMonth {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/get_nanosecond.rs

@@ -20,7 +20,10 @@ impl Command for GetNanosecond {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -40,14 +43,6 @@ impl Command for GetNanosecond {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/get_ordinal.rs

@@ -20,7 +20,10 @@ impl Command for GetOrdinal {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -40,14 +43,6 @@ impl Command for GetOrdinal {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/get_second.rs

@@ -20,7 +20,10 @@ impl Command for GetSecond {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -40,14 +43,6 @@ impl Command for GetSecond {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/get_week.rs

@@ -20,7 +20,10 @@ impl Command for GetWeek {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -40,14 +43,6 @@ impl Command for GetWeek {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/get_weekday.rs

@@ -20,7 +20,10 @@ impl Command for GetWeekDay {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -40,14 +43,6 @@ impl Command for GetWeekDay {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/date/get_year.rs

@@ -20,7 +20,10 @@ impl Command for GetYear {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -40,14 +43,6 @@ impl Command for GetYear {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/indexes/arg_sort.rs

@@ -23,6 +23,8 @@ impl Command for ArgSort {
         Signature::build(self.name())
             .switch("reverse", "reverse order", Some('r'))
             .switch("nulls-last", "nulls ordered last", Some('n'))
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -67,14 +69,6 @@ impl Command for ArgSort {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/indexes/arg_true.rs

@@ -20,7 +20,10 @@ impl Command for ArgTrue {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -38,14 +41,6 @@ impl Command for ArgTrue {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/indexes/arg_unique.rs

@@ -20,7 +20,10 @@ impl Command for ArgUnique {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -38,14 +41,6 @@ impl Command for ArgUnique {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/indexes/set_with_idx.rs

@@ -29,6 +29,8 @@ impl Command for SetWithIndex {
                 "list of indices indicating where to set the value",
                 Some('i'),
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -56,14 +58,6 @@ impl Command for SetWithIndex {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/masks/is_duplicated.rs

@@ -20,7 +20,10 @@ impl Command for IsDuplicated {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -46,14 +49,6 @@ impl Command for IsDuplicated {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/masks/is_in.rs

@@ -23,6 +23,8 @@ impl Command for IsIn {
     fn signature(&self) -> Signature {
         Signature::build(self.name())
             .required("other", SyntaxShape::Any, "right series")
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -50,14 +52,6 @@ impl Command for IsIn {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/masks/is_not_null.rs

@@ -19,7 +19,10 @@ impl Command for IsNotNull {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -44,14 +47,6 @@ impl Command for IsNotNull {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/masks/is_null.rs

@@ -19,7 +19,10 @@ impl Command for IsNull {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -44,14 +47,6 @@ impl Command for IsNull {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/masks/is_unique.rs

@@ -20,7 +20,10 @@ impl Command for IsUnique {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -46,14 +49,6 @@ impl Command for IsUnique {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/masks/not.rs

@@ -21,7 +21,10 @@ impl Command for NotSeries {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -43,14 +46,6 @@ impl Command for NotSeries {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/masks/set.rs

@@ -29,6 +29,8 @@ impl Command for SetSeries {
                 "mask indicating insertions",
                 Some('m'),
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -55,14 +57,6 @@ impl Command for SetSeries {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/n_null.rs

@@ -19,7 +19,10 @@ impl Command for NNull {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -38,14 +41,6 @@ impl Command for NNull {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/n_unique.rs

@@ -18,7 +18,10 @@ impl Command for NUnique {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build(self.name()).category(Category::Custom("dataframe".into()))
+        Signature::build(self.name())
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
+            .category(Category::Custom("dataframe".into()))
     }
 
     fn examples(&self) -> Vec<Example> {
@@ -36,14 +39,6 @@ impl Command for NUnique {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/rolling.rs

@@ -59,6 +59,8 @@ impl Command for Rolling {
         Signature::build(self.name())
             .required("type", SyntaxShape::String, "rolling operation")
             .required("window", SyntaxShape::Int, "Window size for rolling")
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -101,14 +103,6 @@ impl Command for Rolling {
         ]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/shift.rs

@@ -30,6 +30,8 @@ impl Command for Shift {
                 "Expression used to fill the null values (lazy df)",
                 Some('f'),
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe or lazyframe".into()))
     }
 
@@ -48,14 +50,6 @@ impl Command for Shift {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,

crates/nu-command/src/dataframe/series/string/concatenate.rs

@@ -27,6 +27,8 @@ impl Command for Concatenate {
                 SyntaxShape::Any,
                 "Other array with string to be concatenated",
             )
+            .input_type(Type::Custom("dataframe".into()))
+            .output_type(Type::Custom("dataframe".into()))
             .category(Category::Custom("dataframe".into()))
     }
 
@@ -50,14 +52,6 @@ impl Command for Concatenate {
         }]
     }
 
-    fn input_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
-    fn output_type(&self) -> Type {
-        Type::Custom("dataframe".into())
-    }
-
     fn run(
         &self,
         engine_state: &EngineState,