Add subcommands. Switch from-* and to-* to them (#1708)

crates/nu-cli/src/cli.rs

@@ -320,6 +320,7 @@ pub fn create_default_context(
             whole_stream_command(Histogram),
             whole_stream_command(Sum),
             // File format output
+            whole_stream_command(To),
             whole_stream_command(ToBSON),
             whole_stream_command(ToCSV),
             whole_stream_command(ToHTML),
@@ -332,6 +333,7 @@ pub fn create_default_context(
             whole_stream_command(ToURL),
             whole_stream_command(ToYAML),
             // File format input
+            whole_stream_command(From),
             whole_stream_command(FromCSV),
             whole_stream_command(FromEML),
             whole_stream_command(FromTSV),

crates/nu-cli/src/commands.rs

@@ -31,6 +31,7 @@ pub(crate) mod evaluate_by;
 pub(crate) mod exit;
 pub(crate) mod first;
 pub(crate) mod format;
+pub(crate) mod from;
 pub(crate) mod from_bson;
 pub(crate) mod from_csv;
 pub(crate) mod from_eml;
@@ -101,6 +102,7 @@ pub(crate) mod sum;
 pub(crate) mod t_sort_by;
 pub(crate) mod table;
 pub(crate) mod tags;
+pub(crate) mod to;
 pub(crate) mod to_bson;
 pub(crate) mod to_csv;
 pub(crate) mod to_html;
@@ -150,6 +152,7 @@ pub(crate) use evaluate_by::EvaluateBy;
 pub(crate) use exit::Exit;
 pub(crate) use first::First;
 pub(crate) use format::Format;
+pub(crate) use from::From;
 pub(crate) use from_bson::FromBSON;
 pub(crate) use from_csv::FromCSV;
 pub(crate) use from_eml::FromEML;
@@ -219,6 +222,7 @@ pub(crate) use sum::Sum;
 pub(crate) use t_sort_by::TSortBy;
 pub(crate) use table::Table;
 pub(crate) use tags::Tags;
+pub(crate) use to::To;
 pub(crate) use to_bson::ToBSON;
 pub(crate) use to_csv::ToCSV;
 pub(crate) use to_html::ToHTML;

crates/nu-cli/src/commands/classified/internal.rs

@@ -51,7 +51,7 @@ pub(crate) fn run_internal_command(
                     }
                     CommandAction::AutoConvert(tagged_contents, extension) => {
                         let contents_tag = tagged_contents.tag.clone();
-                        let command_name = format!("from-{}", extension);
+                        let command_name = format!("from {}", extension);
                         let command = command.clone();
                         if let Some(converter) = context.registry.get_command(&command_name) {
                             let new_args = RawCommandArgs {

crates/nu-cli/src/commands/command.rs

@@ -407,7 +407,7 @@ impl Command {
 
     pub fn run(&self, args: CommandArgs, registry: &CommandRegistry) -> OutputStream {
         if args.call_info.switch_present("help") {
-            get_help(self.name(), self.usage(), self.signature()).into()
+            get_help(self.name(), self.usage(), self.signature(), registry).into()
         } else {
             match self.0.run(args, registry) {
                 Ok(stream) => stream,

crates/nu-cli/src/commands/enter.rs

@@ -95,7 +95,7 @@ fn enter(
                     let tagged_contents = contents.into_value(&contents_tag);
 
                     if let Some(extension) = file_extension {
-                        let command_name = format!("from-{}", extension);
+                        let command_name = format!("from {}", extension);
                         if let Some(converter) =
                             registry.get_command(&command_name)
                         {

crates/nu-cli/src/commands/from.rs

@@ -0,0 +1,31 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::Signature;
+
+pub struct From;
+
+impl WholeStreamCommand for From {
+    fn name(&self) -> &str {
+        "from"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("from")
+    }
+
+    fn usage(&self) -> &str {
+        "Parse content (string or binary) as a table."
+    }
+
+    fn run(
+        &self,
+        _args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        Ok(
+            crate::commands::help::get_help(self.name(), self.usage(), self.signature(), registry)
+                .into(),
+        )
+    }
+}

crates/nu-cli/src/commands/from_bson.rs

@@ -10,15 +10,15 @@ pub struct FromBSON;
 
 impl WholeStreamCommand for FromBSON {
     fn name(&self) -> &str {
-        "from-bson"
+        "from bson"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-bson")
+        Signature::build("from bson")
     }
 
     fn usage(&self) -> &str {
-        "Parse text as .bson and create table."
+        "Parse binary as .bson and create table."
     }
 
     fn run(

crates/nu-cli/src/commands/from_csv.rs

@@ -14,11 +14,11 @@ pub struct FromCSVArgs {
 
 impl WholeStreamCommand for FromCSV {
     fn name(&self) -> &str {
-        "from-csv"
+        "from csv"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-csv")
+        Signature::build("from csv")
             .named(
                 "separator",
                 SyntaxShape::String,

crates/nu-cli/src/commands/from_eml.rs

@@ -18,11 +18,11 @@ pub struct FromEMLArgs {
 
 impl WholeStreamCommand for FromEML {
     fn name(&self) -> &str {
-        "from-eml"
+        "from eml"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-eml").named(
+        Signature::build("from eml").named(
             "preview-body",
             SyntaxShape::Int,
             "How many bytes of the body to preview",

crates/nu-cli/src/commands/from_ics.rs

@@ -11,11 +11,11 @@ pub struct FromIcs;
 
 impl WholeStreamCommand for FromIcs {
     fn name(&self) -> &str {
-        "from-ics"
+        "from ics"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-ics")
+        Signature::build("from ics")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/from_ini.rs

@@ -8,11 +8,11 @@ pub struct FromINI;
 
 impl WholeStreamCommand for FromINI {
     fn name(&self) -> &str {
-        "from-ini"
+        "from ini"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-ini")
+        Signature::build("from ini")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/from_json.rs

@@ -12,11 +12,11 @@ pub struct FromJSONArgs {
 
 impl WholeStreamCommand for FromJSON {
     fn name(&self) -> &str {
-        "from-json"
+        "from json"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-json").switch(
+        Signature::build("from json").switch(
             "objects",
             "treat each line as a separate value",
             Some('o'),

crates/nu-cli/src/commands/from_ods.rs

@@ -15,11 +15,11 @@ pub struct FromODSArgs {
 
 impl WholeStreamCommand for FromODS {
     fn name(&self) -> &str {
-        "from-ods"
+        "from ods"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-ods").switch(
+        Signature::build("from ods").switch(
             "headerless",
             "don't treat the first row as column names",
             None,

crates/nu-cli/src/commands/from_sqlite.rs

@@ -10,11 +10,11 @@ pub struct FromSQLite;
 
 impl WholeStreamCommand for FromSQLite {
     fn name(&self) -> &str {
-        "from-sqlite"
+        "from sqlite"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-sqlite")
+        Signature::build("from sqlite")
     }
 
     fn usage(&self) -> &str {
@@ -34,11 +34,11 @@ pub struct FromDB;
 
 impl WholeStreamCommand for FromDB {
     fn name(&self) -> &str {
-        "from-db"
+        "from db"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-db")
+        Signature::build("from db")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/from_ssv.rs

@@ -17,7 +17,7 @@ pub struct FromSSVArgs {
     minimum_spaces: Option<Tagged<usize>>,
 }
 
-const STRING_REPRESENTATION: &str = "from-ssv";
+const STRING_REPRESENTATION: &str = "from ssv";
 const DEFAULT_MINIMUM_SPACES: usize = 2;
 
 impl WholeStreamCommand for FromSSV {

crates/nu-cli/src/commands/from_toml.rs

@@ -7,11 +7,11 @@ pub struct FromTOML;
 
 impl WholeStreamCommand for FromTOML {
     fn name(&self) -> &str {
-        "from-toml"
+        "from toml"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-toml")
+        Signature::build("from toml")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/from_tsv.rs

@@ -13,11 +13,11 @@ pub struct FromTSVArgs {
 
 impl WholeStreamCommand for FromTSV {
     fn name(&self) -> &str {
-        "from-tsv"
+        "from tsv"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-tsv").switch(
+        Signature::build("from tsv").switch(
             "headerless",
             "don't treat the first row as column names",
             None,

crates/nu-cli/src/commands/from_url.rs

@@ -7,11 +7,11 @@ pub struct FromURL;
 
 impl WholeStreamCommand for FromURL {
     fn name(&self) -> &str {
-        "from-url"
+        "from url"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-url")
+        Signature::build("from url")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/from_vcf.rs

@@ -11,11 +11,11 @@ pub struct FromVcf;
 
 impl WholeStreamCommand for FromVcf {
     fn name(&self) -> &str {
-        "from-vcf"
+        "from vcf"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-vcf")
+        Signature::build("from vcf")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/from_xlsx.rs

@@ -15,11 +15,11 @@ pub struct FromXLSXArgs {
 
 impl WholeStreamCommand for FromXLSX {
     fn name(&self) -> &str {
-        "from-xlsx"
+        "from xlsx"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-xlsx").switch(
+        Signature::build("from xlsx").switch(
             "headerless",
             "don't treat the first row as column names",
             None,

crates/nu-cli/src/commands/from_xml.rs

@@ -7,11 +7,11 @@ pub struct FromXML;
 
 impl WholeStreamCommand for FromXML {
     fn name(&self) -> &str {
-        "from-xml"
+        "from xml"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-xml")
+        Signature::build("from xml")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/from_yaml.rs

@@ -7,11 +7,11 @@ pub struct FromYAML;
 
 impl WholeStreamCommand for FromYAML {
     fn name(&self) -> &str {
-        "from-yaml"
+        "from yaml"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-yaml")
+        Signature::build("from yaml")
     }
 
     fn usage(&self) -> &str {
@@ -31,11 +31,11 @@ pub struct FromYML;
 
 impl WholeStreamCommand for FromYML {
     fn name(&self) -> &str {
-        "from-yml"
+        "from yml"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("from-yml")
+        Signature::build("from yml")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/help.rs

@@ -14,7 +14,7 @@ pub struct Help;
 
 #[derive(Deserialize)]
 pub struct HelpArgs {
-    command: Option<Tagged<String>>,
+    rest: Vec<Tagged<String>>,
 }
 
 impl WholeStreamCommand for Help {
@@ -23,11 +23,7 @@ impl WholeStreamCommand for Help {
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("help").optional(
-            "command",
-            SyntaxShape::String,
-            "the name of command(s) to get help on",
-        )
+        Signature::build("help").rest(SyntaxShape::String, "the name of command to get help on")
     }
 
     fn usage(&self) -> &str {
@@ -44,15 +40,19 @@ impl WholeStreamCommand for Help {
 }
 
 fn help(
-    HelpArgs { command }: HelpArgs,
+    HelpArgs { rest }: HelpArgs,
     RunnableContext { registry, name, .. }: RunnableContext,
 ) -> Result<OutputStream, ShellError> {
-    if let Some(document) = command {
+    if let Some(document) = rest.get(0) {
         let mut help = VecDeque::new();
         if document.item == "commands" {
             let mut sorted_names = registry.names();
             sorted_names.sort();
             for cmd in sorted_names {
+                // If it's a subcommand, don't list it during the commands list
+                if cmd.contains(' ') {
+                    continue;
+                }
                 let mut short_desc = TaggedDictBuilder::new(name.clone());
                 let document_tag = document.tag.clone();
                 let value = command_dict(
@@ -82,13 +82,31 @@ fn help(
 
                 help.push_back(ReturnSuccess::value(short_desc.into_value()));
             }
+        } else if rest.len() == 2 {
+            // Check for a subcommand
+            let command_name = format!("{} {}", rest[0].item, rest[1].item);
+            if let Some(command) = registry.get_command(&command_name) {
+                return Ok(get_help(
+                    &command.name(),
+                    &command.usage(),
+                    command.signature(),
+                    &registry,
+                )
+                .into());
+            }
         } else if let Some(command) = registry.get_command(&document.item) {
-            return Ok(get_help(&command.name(), &command.usage(), command.signature()).into());
+            return Ok(get_help(
+                &command.name(),
+                &command.usage(),
+                command.signature(),
+                &registry,
+            )
+            .into());
         } else {
             return Err(ShellError::labeled_error(
                 "Can't find command (use 'help commands' for full list)",
                 "can't find command",
-                document.tag,
+                document.tag.span,
             ));
         }
         let help = futures::stream::iter(help);
@@ -128,6 +146,7 @@ pub(crate) fn get_help(
     cmd_name: &str,
     cmd_usage: &str,
     cmd_sig: Signature,
+    registry: &CommandRegistry,
 ) -> impl Into<OutputStream> {
     let mut help = VecDeque::new();
     let mut long_desc = String::new();
@@ -137,6 +156,15 @@ pub(crate) fn get_help(
 
     let signature = cmd_sig;
 
+    let mut subcommands = String::new();
+    for name in registry.names() {
+        if name.starts_with(&format!("{} ", cmd_name)) {
+            let subcommand = registry.get_command(&name).expect("This shouldn't happen");
+
+            subcommands.push_str(&format!("  {} - {}\n", name, subcommand.usage()));
+        }
+    }
+
     let mut one_liner = String::new();
     one_liner.push_str(&signature.name);
     one_liner.push_str(" ");
@@ -156,14 +184,23 @@ pub(crate) fn get_help(
         one_liner.push_str(" ...args");
     }
 
+    if !subcommands.is_empty() {
+        one_liner.push_str("<subcommand> ");
+    }
+
     if !signature.named.is_empty() {
         one_liner.push_str("{flags} ");
     }
 
     long_desc.push_str(&format!("\nUsage:\n  > {}\n", one_liner));
 
+    if !subcommands.is_empty() {
+        long_desc.push_str("\nSubcommands:\n");
+        long_desc.push_str(&subcommands);
+    }
+
     if !signature.positional.is_empty() || signature.rest_positional.is_some() {
-        long_desc.push_str("\nparameters:\n");
+        long_desc.push_str("\nParameters:\n");
         for positional in signature.positional {
             match positional.0 {
                 PositionalType::Mandatory(name, _m) => {
@@ -180,7 +217,7 @@ pub(crate) fn get_help(
         }
     }
     if !signature.named.is_empty() {
-        long_desc.push_str("\nflags:\n");
+        long_desc.push_str("\nFlags:\n");
         for (flag, ty) in signature.named {
             let msg = match ty.0 {
                 NamedType::Switch(s) => {

crates/nu-cli/src/commands/save.rs

@@ -221,7 +221,7 @@ fn save(
         let content : Result<Vec<u8>, ShellError> = 'scope: loop {
             break if !save_raw {
                 if let Some(extension) = full_path.extension() {
-                    let command_name = format!("to-{}", extension.to_string_lossy());
+                    let command_name = format!("to {}", extension.to_string_lossy());
                     if let Some(converter) = registry.get_command(&command_name) {
                         let new_args = RawCommandArgs {
                             host,

crates/nu-cli/src/commands/to.rs

@@ -0,0 +1,31 @@
+use crate::commands::WholeStreamCommand;
+use crate::prelude::*;
+use nu_errors::ShellError;
+use nu_protocol::Signature;
+
+pub struct To;
+
+impl WholeStreamCommand for To {
+    fn name(&self) -> &str {
+        "to"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("to")
+    }
+
+    fn usage(&self) -> &str {
+        "Convert table into an output format."
+    }
+
+    fn run(
+        &self,
+        _args: CommandArgs,
+        registry: &CommandRegistry,
+    ) -> Result<OutputStream, ShellError> {
+        Ok(
+            crate::commands::help::get_help(self.name(), self.usage(), self.signature(), registry)
+                .into(),
+        )
+    }
+}

crates/nu-cli/src/commands/to_bson.rs

@@ -12,11 +12,11 @@ pub struct ToBSON;
 
 impl WholeStreamCommand for ToBSON {
     fn name(&self) -> &str {
-        "to-bson"
+        "to bson"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-bson")
+        Signature::build("to bson")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/to_csv.rs

@@ -14,11 +14,11 @@ pub struct ToCSVArgs {
 
 impl WholeStreamCommand for ToCSV {
     fn name(&self) -> &str {
-        "to-csv"
+        "to csv"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-csv")
+        Signature::build("to csv")
             .named(
                 "separator",
                 SyntaxShape::String,

crates/nu-cli/src/commands/to_html.rs

@@ -10,11 +10,11 @@ pub struct ToHTML;
 
 impl WholeStreamCommand for ToHTML {
     fn name(&self) -> &str {
-        "to-html"
+        "to html"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-html")
+        Signature::build("to html")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/to_json.rs

@@ -7,11 +7,11 @@ pub struct ToJSON;
 
 impl WholeStreamCommand for ToJSON {
     fn name(&self) -> &str {
-        "to-json"
+        "to json"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-json")
+        Signature::build("to json")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/to_md.rs

@@ -9,11 +9,11 @@ pub struct ToMarkdown;
 
 impl WholeStreamCommand for ToMarkdown {
     fn name(&self) -> &str {
-        "to-md"
+        "to md"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-md")
+        Signature::build("to md")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/to_sqlite.rs

@@ -10,11 +10,11 @@ pub struct ToSQLite;
 
 impl WholeStreamCommand for ToSQLite {
     fn name(&self) -> &str {
-        "to-sqlite"
+        "to sqlite"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-sqlite")
+        Signature::build("to sqlite")
     }
 
     fn usage(&self) -> &str {
@@ -38,11 +38,11 @@ pub struct ToDB;
 
 impl WholeStreamCommand for ToDB {
     fn name(&self) -> &str {
-        "to-db"
+        "to db"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-db")
+        Signature::build("to db")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/to_toml.rs

@@ -7,11 +7,11 @@ pub struct ToTOML;
 
 impl WholeStreamCommand for ToTOML {
     fn name(&self) -> &str {
-        "to-toml"
+        "to toml"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-toml")
+        Signature::build("to toml")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/to_tsv.rs

@@ -13,11 +13,11 @@ pub struct ToTSVArgs {
 
 impl WholeStreamCommand for ToTSV {
     fn name(&self) -> &str {
-        "to-tsv"
+        "to tsv"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-tsv").switch(
+        Signature::build("to tsv").switch(
             "headerless",
             "do not output the column names as the first row",
             None,

crates/nu-cli/src/commands/to_url.rs

@@ -7,11 +7,11 @@ pub struct ToURL;
 
 impl WholeStreamCommand for ToURL {
     fn name(&self) -> &str {
-        "to-url"
+        "to url"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-url")
+        Signature::build("to url")
     }
 
     fn usage(&self) -> &str {

crates/nu-cli/src/commands/to_yaml.rs

@@ -7,11 +7,11 @@ pub struct ToYAML;
 
 impl WholeStreamCommand for ToYAML {
     fn name(&self) -> &str {
-        "to-yaml"
+        "to yaml"
     }
 
     fn signature(&self) -> Signature {
-        Signature::build("to-yaml")
+        Signature::build("to yaml")
     }
 
     fn usage(&self) -> &str {