a new command to query the nushell internals (#3704)

* a new command to query the nushell internals

* added signature

* a little cleanup

Cargo.lock

@@ -4438,7 +4438,7 @@ dependencies = [
  "lz4",
  "num-bigint 0.4.0",
  "parquet-format",
- "rand 0.8.3",
+ "rand 0.8.4",
  "snap",
  "thrift",
  "zstd",

crates/nu-command/src/commands/core_commands/help.rs

@@ -44,11 +44,11 @@ fn help(args: CommandArgs) -> Result<ActionStream, ShellError> {
 
             let (mut subcommand_names, command_names) = sorted_names
                 .into_iter()
-                // Internal only commands shouldn't be displayed
+                // private only commands shouldn't be displayed
                 .filter(|cmd_name| {
                     scope
                         .get_command(cmd_name)
-                        .filter(|command| !command.is_internal())
+                        .filter(|command| !command.is_private())
                         .is_some()
                 })
                 .partition::<Vec<_>, _>(|cmd_name| cmd_name.contains(' '));

crates/nu-command/src/commands/platform/lang.rs

@@ -0,0 +1,229 @@
+use crate::prelude::*;
+use indexmap::IndexMap;
+use nu_engine::WholeStreamCommand;
+use nu_errors::ShellError;
+use nu_protocol::{Dictionary, Signature, UntaggedValue, Value};
+
+pub struct Lang;
+
+impl WholeStreamCommand for Lang {
+    fn name(&self) -> &str {
+        "lang"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("lang")
+    }
+
+    fn usage(&self) -> &str {
+        "Returns the nushell-lang information"
+    }
+
+    fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
+        let tag = args.call_info.name_tag.clone();
+        let full_commands = args.context.scope.get_commands_info();
+        let mut cmd_vec_deque = VecDeque::new();
+        for (key, cmd) in full_commands {
+            let mut indexmap = IndexMap::new();
+            let mut sig = cmd.signature();
+            // eprintln!("{}", get_signature(&sig));
+            indexmap.insert(
+                "name".to_string(),
+                UntaggedValue::string(key).into_value(&tag),
+            );
+            indexmap.insert(
+                "usage".to_string(),
+                UntaggedValue::string(cmd.usage().to_string()).into_value(&tag),
+            );
+            // let sig_deser = serde_json::to_string(&sig).unwrap();
+            // indexmap.insert(
+            //     "signature".to_string(),
+            //     UntaggedValue::string(sig_deser).into_value(&tag),
+            // );
+            let signature_table = get_signature(&mut sig, tag.clone());
+            indexmap.insert(
+                "signature".to_string(),
+                UntaggedValue::Table(signature_table).into_value(&tag),
+            );
+            indexmap.insert(
+                "is_filter".to_string(),
+                UntaggedValue::boolean(sig.is_filter).into_value(&tag),
+            );
+            indexmap.insert(
+                "is_builtin".to_string(),
+                UntaggedValue::boolean(cmd.is_builtin()).into_value(&tag),
+            );
+            indexmap.insert(
+                "is_sub".to_string(),
+                UntaggedValue::boolean(cmd.is_sub()).into_value(&tag),
+            );
+            indexmap.insert(
+                "is_plugin".to_string(),
+                UntaggedValue::boolean(cmd.is_plugin()).into_value(&tag),
+            );
+            indexmap.insert(
+                "is_custom".to_string(),
+                UntaggedValue::boolean(cmd.is_custom()).into_value(&tag),
+            );
+            indexmap.insert(
+                "is_private".to_string(),
+                UntaggedValue::boolean(cmd.is_private()).into_value(&tag),
+            );
+            indexmap.insert(
+                "is_binary".to_string(),
+                UntaggedValue::boolean(cmd.is_binary()).into_value(&tag),
+            );
+            indexmap.insert(
+                "extra_usage".to_string(),
+                UntaggedValue::string(cmd.extra_usage().to_string()).into_value(&tag),
+            );
+
+            cmd_vec_deque
+                .push_back(UntaggedValue::Row(Dictionary::from(indexmap)).into_value(&tag));
+        }
+        Ok(cmd_vec_deque.into_iter().into_output_stream())
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "Query command information from Nushell",
+            example: "lang",
+            result: None,
+        }]
+    }
+}
+
+fn get_signature(sig: &mut Signature, tag: Tag) -> Vec<Value> {
+    sig.remove_named("help");
+    let p = &sig.positional;
+    let r = &sig.rest_positional;
+    let n = &sig.named;
+    let name = &sig.name;
+    let mut sig_vec: Vec<Value> = Vec::new();
+
+    for item in p {
+        let mut indexmap = IndexMap::new();
+
+        let (parameter, syntax_shape) = item.0.get_type_description();
+        let description = &item.1;
+        // let output = format!(
+        //     "Positional|{}|{}|{}|{}\n",
+        //     name, parameter, syntax_shape, description
+        // );
+        // eprintln!("{}", output);
+
+        indexmap.insert(
+            "cmd_name".to_string(),
+            UntaggedValue::string(name).into_value(&tag),
+        );
+        indexmap.insert(
+            "parameter_name".to_string(),
+            UntaggedValue::string(parameter).into_value(&tag),
+        );
+        indexmap.insert(
+            "parameter_type".to_string(),
+            UntaggedValue::string("positional".to_string()).into_value(&tag),
+        );
+        indexmap.insert(
+            "syntax_shape".to_string(),
+            UntaggedValue::string(syntax_shape).into_value(&tag),
+        );
+        indexmap.insert(
+            "description".to_string(),
+            UntaggedValue::string(description).into_value(&tag),
+        );
+        indexmap.insert(
+            "flag_name".to_string(),
+            UntaggedValue::string("".to_string()).into_value(&tag),
+        );
+        indexmap.insert(
+            "flag_type".to_string(),
+            UntaggedValue::string("".to_string()).into_value(&tag),
+        );
+
+        sig_vec.push(UntaggedValue::Row(Dictionary::from(indexmap)).into_value(&tag));
+    }
+
+    match r {
+        Some((shape, desc)) => {
+            let mut indexmap = IndexMap::new();
+            // let output = format!("Rest|{}|{}|{}\n", name, shape.syntax_shape_name(), desc);
+            // eprintln!("{}", output);
+
+            indexmap.insert(
+                "cmd_name".to_string(),
+                UntaggedValue::string(name).into_value(&tag),
+            );
+            indexmap.insert(
+                "parameter_name".to_string(),
+                UntaggedValue::string("".to_string()).into_value(&tag),
+            );
+            indexmap.insert(
+                "parameter_type".to_string(),
+                UntaggedValue::string("rest".to_string()).into_value(&tag),
+            );
+            indexmap.insert(
+                "syntax_shape".to_string(),
+                UntaggedValue::string(shape.syntax_shape_name()).into_value(&tag),
+            );
+            indexmap.insert(
+                "description".to_string(),
+                UntaggedValue::string(desc).into_value(&tag),
+            );
+            indexmap.insert(
+                "flag_name".to_string(),
+                UntaggedValue::string("".to_string()).into_value(&tag),
+            );
+            indexmap.insert(
+                "flag_type".to_string(),
+                UntaggedValue::string("".to_string()).into_value(&tag),
+            );
+
+            sig_vec.push(UntaggedValue::Row(Dictionary::from(indexmap)).into_value(&tag));
+        }
+        None => {}
+    }
+
+    for (parameter, (b, description)) in n {
+        let mut indexmap = IndexMap::new();
+
+        let (named_type, flag_name, shape) = b.get_type_description();
+        // let output = format!(
+        //     "Named|{}|{}|{}|{}|{}|{}\n",
+        //     name, parameter, named_type, flag_name, shape, description
+        // );
+        // eprint!("{}", output);
+
+        indexmap.insert(
+            "cmd_name".to_string(),
+            UntaggedValue::string(name).into_value(&tag),
+        );
+        indexmap.insert(
+            "parameter_name".to_string(),
+            UntaggedValue::string(parameter).into_value(&tag),
+        );
+        indexmap.insert(
+            "parameter_type".to_string(),
+            UntaggedValue::string("named".to_string()).into_value(&tag),
+        );
+        indexmap.insert(
+            "syntax_shape".to_string(),
+            UntaggedValue::string(shape).into_value(&tag),
+        );
+        indexmap.insert(
+            "description".to_string(),
+            UntaggedValue::string(description).into_value(&tag),
+        );
+        indexmap.insert(
+            "flag_name".to_string(),
+            UntaggedValue::string(flag_name).into_value(&tag),
+        );
+        indexmap.insert(
+            "flag_type".to_string(),
+            UntaggedValue::string(named_type).into_value(&tag),
+        );
+        sig_vec.push(UntaggedValue::Row(Dictionary::from(indexmap)).into_value(&tag));
+    }
+
+    sig_vec
+}

crates/nu-command/src/commands/platform/mod.rs

@@ -6,6 +6,7 @@ mod clip;
 mod du;
 mod exec;
 mod kill;
+mod lang;
 #[cfg(feature = "clipboard-cli")]
 mod paste;
 mod pwd;
@@ -22,6 +23,7 @@ pub use clip::Clip;
 pub use du::Du;
 pub use exec::Exec;
 pub use kill::Kill;
+pub use lang::Lang;
 #[cfg(feature = "clipboard-cli")]
 pub use paste::Paste;
 pub use pwd::Pwd;

crates/nu-command/src/commands/platform/run_external.rs

@@ -58,7 +58,7 @@ impl WholeStreamCommand for RunExternalCommand {
         }]
     }
 
-    fn is_internal(&self) -> bool {
+    fn is_private(&self) -> bool {
         true
     }
 

crates/nu-command/src/default_context.rs

@@ -69,6 +69,7 @@ pub fn create_default_context(interactive: bool) -> Result<EvaluationContext, Bo
             whole_stream_command(Benchmark),
             // Metadata
             whole_stream_command(Tags),
+            whole_stream_command(Lang),
             // Shells
             whole_stream_command(Next),
             whole_stream_command(Previous),

crates/nu-engine/src/evaluate/mod.rs

@@ -2,7 +2,7 @@ pub(crate) mod block;
 pub(crate) mod evaluate_args;
 pub mod evaluator;
 pub(crate) mod expr;
-pub(crate) mod internal;
+pub mod internal;
 pub(crate) mod operator;
 pub(crate) mod scope;
 pub(crate) mod variables;

crates/nu-engine/src/evaluate/scope.rs

@@ -65,6 +65,20 @@ impl Scope {
         output.sorted_by(|k1, _v1, k2, _v2| k1.cmp(k2)).collect()
     }
 
+    pub fn get_commands_info(&self) -> IndexMap<String, Command> {
+        let mut output: IndexMap<String, Command> = IndexMap::new();
+
+        for frame in self.frames.lock().iter().rev() {
+            for (name, command) in frame.commands.iter() {
+                if !output.contains_key(name) {
+                    output.insert(name.clone(), command.clone());
+                }
+            }
+        }
+
+        output.sorted_by(|k1, _v1, k2, _v2| k1.cmp(k2)).collect()
+    }
+
     pub fn get_variable_names(&self) -> Vec<String> {
         self.get_vars().iter().map(|(k, _)| k.to_string()).collect()
     }

crates/nu-engine/src/lib.rs

@@ -3,7 +3,7 @@ mod command_args;
 mod config_holder;
 pub mod documentation;
 mod env;
-mod evaluate;
+pub mod evaluate;
 pub mod evaluation_context;
 mod example;
 pub mod filesystem;

crates/nu-engine/src/plugin/run_plugin.rs

@@ -111,9 +111,21 @@ impl WholeStreamCommand for PluginFilter {
         &self.config.usage
     }
 
+    fn extra_usage(&self) -> &str {
+        &self.config.extra_usage
+    }
+
     fn run_with_actions(&self, args: CommandArgs) -> Result<ActionStream, ShellError> {
         run_filter(self.path.clone(), args)
     }
+
+    fn is_plugin(&self) -> bool {
+        true
+    }
+
+    fn is_builtin(&self) -> bool {
+        false
+    }
 }
 
 fn run_filter(path: String, args: CommandArgs) -> Result<ActionStream, ShellError> {
@@ -383,9 +395,21 @@ impl WholeStreamCommand for PluginSink {
         &self.config.usage
     }
 
+    fn extra_usage(&self) -> &str {
+        &self.config.extra_usage
+    }
+
     fn run_with_actions(&self, args: CommandArgs) -> Result<ActionStream, ShellError> {
         run_sink(self.path.clone(), args)
     }
+
+    fn is_plugin(&self) -> bool {
+        true
+    }
+
+    fn is_builtin(&self) -> bool {
+        false
+    }
 }
 
 fn run_sink(path: String, args: CommandArgs) -> Result<ActionStream, ShellError> {

crates/nu-engine/src/whole_stream_command.rs

@@ -47,19 +47,38 @@ pub trait WholeStreamCommand: Send + Sync {
     }
 
     // Commands that are not meant to be run by users
-    fn is_internal(&self) -> bool {
+    fn is_private(&self) -> bool {
         false
     }
 
     fn examples(&self) -> Vec<Example> {
         Vec::new()
     }
+
+    // This is a built-in command
+    fn is_builtin(&self) -> bool {
+        true
+    }
+
+    // Is a sub command
+    fn is_sub(&self) -> bool {
+        self.name().contains(' ')
+    }
+
+    // Is a plugin command
+    fn is_plugin(&self) -> bool {
+        false
+    }
+
+    // Is a custom command i.e. def blah [] { }
+    fn is_custom(&self) -> bool {
+        false
+    }
 }
 
 // Custom commands are blocks, so we can use the information in the block to also
 // implement a WholeStreamCommand
 #[allow(clippy::suspicious_else_formatting)]
-
 impl WholeStreamCommand for Arc<Block> {
     fn name(&self) -> &str {
         &self.params.name
@@ -73,6 +92,10 @@ impl WholeStreamCommand for Arc<Block> {
         &self.params.usage
     }
 
+    fn extra_usage(&self) -> &str {
+        &self.params.extra_usage
+    }
+
     fn run(&self, args: CommandArgs) -> Result<OutputStream, ShellError> {
         let call_info = args.call_info.clone();
 
@@ -184,13 +207,21 @@ impl WholeStreamCommand for Arc<Block> {
         false
     }
 
-    fn is_internal(&self) -> bool {
+    fn is_private(&self) -> bool {
         false
     }
 
     fn examples(&self) -> Vec<Example> {
         vec![]
     }
+
+    fn is_custom(&self) -> bool {
+        true
+    }
+
+    fn is_builtin(&self) -> bool {
+        false
+    }
 }
 
 #[derive(Clone)]
@@ -228,6 +259,10 @@ impl Command {
         self.0.usage()
     }
 
+    pub fn extra_usage(&self) -> &str {
+        self.0.extra_usage()
+    }
+
     pub fn examples(&self) -> Vec<Example> {
         self.0.examples()
     }
@@ -260,13 +295,29 @@ impl Command {
         self.0.is_binary()
     }
 
-    pub fn is_internal(&self) -> bool {
+    pub fn is_private(&self) -> bool {
-        self.0.is_internal()
+        self.0.is_private()
     }
 
     pub fn stream_command(&self) -> &dyn WholeStreamCommand {
         &*self.0
     }
+
+    pub fn is_builtin(&self) -> bool {
+        self.0.is_builtin()
+    }
+
+    pub fn is_sub(&self) -> bool {
+        self.0.is_sub()
+    }
+
+    pub fn is_plugin(&self) -> bool {
+        self.0.is_plugin()
+    }
+
+    pub fn is_custom(&self) -> bool {
+        self.0.is_custom()
+    }
 }
 
 pub fn whole_stream_command(command: impl WholeStreamCommand + 'static) -> Command {

crates/nu-protocol/src/signature.rs

@@ -23,6 +23,32 @@ impl NamedType {
             NamedType::Optional(s, _) => *s,
         }
     }
+
+    pub fn get_type_description(&self) -> (String, String, String) {
+        let empty_string = ("".to_string(), "".to_string(), "".to_string());
+        match self {
+            NamedType::Switch(f) => match f {
+                Some(flag) => ("switch_flag".to_string(), flag.to_string(), "".to_string()),
+                None => empty_string,
+            },
+            NamedType::Mandatory(f, shape) => match f {
+                Some(flag) => (
+                    "mandatory_flag".to_string(),
+                    flag.to_string(),
+                    shape.syntax_shape_name().to_string(),
+                ),
+                None => empty_string,
+            },
+            NamedType::Optional(f, shape) => match f {
+                Some(flag) => (
+                    "optional_flag".to_string(),
+                    flag.to_string(),
+                    shape.syntax_shape_name().to_string(),
+                ),
+                None => empty_string,
+            },
+        }
+    }
 }
 
 /// The type of positional arguments
@@ -96,6 +122,13 @@ impl PositionalType {
             PositionalType::Optional(_, t) => t,
         }
     }
+
+    pub fn get_type_description(&self) -> (String, String) {
+        match &self {
+            PositionalType::Mandatory(c, s) => (c.to_string(), s.syntax_shape_name().to_string()),
+            PositionalType::Optional(c, s) => (c.to_string(), s.syntax_shape_name().to_string()),
+        }
+    }
 }
 
 type Description = String;
@@ -109,6 +142,8 @@ pub struct Signature {
     pub name: String,
     /// Usage instructions about the command
     pub usage: String,
+    /// Longer or more verbose usage statement
+    pub extra_usage: String,
     /// The list of positional arguments, both required and optional, and their corresponding types and help text
     pub positional: Vec<(PositionalType, Description)>,
     /// After the positional arguments, a catch-all for the rest of the arguments that might follow, their type, and help text
@@ -192,6 +227,7 @@ impl Signature {
         Signature {
             name: name.into(),
             usage: String::new(),
+            extra_usage: String::new(),
             positional: vec![],
             rest_positional: None,
             named: indexmap::indexmap! {"help".into() => (NamedType::Switch(Some('h')), "Display this help message".into())},

crates/nu-protocol/src/syntax_shape.rs

@@ -39,10 +39,9 @@ pub enum SyntaxShape {
     MathExpression,
 }
 
-impl PrettyDebug for SyntaxShape {
+impl SyntaxShape {
-    /// Prepare SyntaxShape for pretty-printing
+    pub fn syntax_shape_name(&self) -> &str {
-    fn pretty(&self) -> DebugDocBuilder {
+        match self {
-        DbgDocBldr::kind(match self {
             SyntaxShape::Any => "any",
             SyntaxShape::String => "string",
             SyntaxShape::FullColumnPath => "column path (with variable)",
@@ -59,6 +58,13 @@ impl PrettyDebug for SyntaxShape {
             SyntaxShape::Operator => "operator",
             SyntaxShape::RowCondition => "condition",
             SyntaxShape::MathExpression => "math expression",
-        })
+        }
+    }
+}
+
+impl PrettyDebug for SyntaxShape {
+    /// Prepare SyntaxShape for pretty-printing
+    fn pretty(&self) -> DebugDocBuilder {
+        DbgDocBldr::kind(self.syntax_shape_name().to_string())
     }
 }