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

crates/nu-protocol/src/engine/command.rs

@@ -1,6 +1,6 @@
 use std::path::PathBuf;
 
-use crate::{ast::Call, BlockId, Example, PipelineData, ShellError, Signature, Type};
+use crate::{ast::Call, BlockId, Example, PipelineData, ShellError, Signature};
 
 use super::{EngineState, Stack};
 
@@ -62,20 +62,6 @@ pub trait Command: Send + Sync + CommandClone {
     fn search_terms(&self) -> Vec<&str> {
         vec![]
     }
-
-    // Command input type. The Type is used during parsing to find the
-    // correct internal command with similar names. The input type is
-    // obtained from the previous expression found in the pipeline
-    fn input_type(&self) -> Type {
-        Type::Any
-    }
-
-    // Command output type. The output type is the value from  the command
-    // It is used during parsing to find the next command in case there
-    // are commands with similar names
-    fn output_type(&self) -> Type {
-        Type::Any
-    }
 }
 
 pub trait CommandClone {

crates/nu-protocol/src/engine/engine_state.rs

@@ -977,7 +977,7 @@ impl<'a> StateWorkingSet<'a> {
 
     pub fn add_decl(&mut self, decl: Box<dyn Command>) -> DeclId {
         let name = decl.name().as_bytes().to_vec();
-        let input_type = decl.input_type();
+        let input_type = decl.signature().input_type;
 
         self.delta.decls.push(decl);
         let decl_id = self.num_decls() - 1;

crates/nu-protocol/src/signature.rs

@@ -10,6 +10,7 @@ use crate::BlockId;
 use crate::PipelineData;
 use crate::ShellError;
 use crate::SyntaxShape;
+use crate::Type;
 use crate::VarId;
 use std::fmt::Write;
 
@@ -106,6 +107,8 @@ pub struct Signature {
     pub optional_positional: Vec<PositionalArg>,
     pub rest_positional: Option<PositionalArg>,
     pub named: Vec<Flag>,
+    pub input_type: Type,
+    pub output_type: Type,
     pub is_filter: bool,
     pub creates_scope: bool,
     // Signature category used to classify commands stored in the list of declarations
@@ -135,6 +138,8 @@ impl Signature {
             required_positional: vec![],
             optional_positional: vec![],
             rest_positional: None,
+            input_type: Type::Any,
+            output_type: Type::Any,
             named: vec![],
             is_filter: false,
             creates_scope: false,
@@ -314,6 +319,18 @@ impl Signature {
         self
     }
 
+    /// Changes the input type of the command signature
+    pub fn input_type(mut self, input_type: Type) -> Signature {
+        self.input_type = input_type;
+        self
+    }
+
+    /// Changes the output type of the command signature
+    pub fn output_type(mut self, output_type: Type) -> Signature {
+        self.output_type = output_type;
+        self
+    }
+
     /// Changes the signature category
     pub fn category(mut self, category: Category) -> Signature {
         self.category = category;