Add format meta command (#11334)

crates/nu-command/src/default_context.rs

@@ -191,6 +191,7 @@ pub fn add_shell_command_context(mut engine_state: EngineState) -> EngineState {
             StrSubstring,
             StrTrim,
             StrUpcase,
+            Format,
             FormatDate,
             FormatDuration,
             FormatFilesize,

crates/nu-command/src/strings/format/format_.rs

@@ -0,0 +1,49 @@
+use nu_engine::get_full_help;
+use nu_protocol::{
+    ast::Call,
+    engine::{Command, EngineState, Stack},
+    Category, IntoPipelineData, PipelineData, ShellError, Signature, Type, Value,
+};
+
+#[derive(Clone)]
+pub struct Format;
+
+impl Command for Format {
+    fn name(&self) -> &str {
+        "format"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build("format")
+            .category(Category::Strings)
+            .input_output_types(vec![(Type::Nothing, Type::String)])
+    }
+
+    fn usage(&self) -> &str {
+        "Various commands for formatting data."
+    }
+
+    fn extra_usage(&self) -> &str {
+        "You must use one of the following subcommands. Using this command as-is will only produce this help message."
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        stack: &mut Stack,
+        call: &Call,
+        _input: PipelineData,
+    ) -> Result<PipelineData, ShellError> {
+        Ok(Value::string(
+            get_full_help(
+                &Format.signature(),
+                &Format.examples(),
+                engine_state,
+                stack,
+                self.is_parser_keyword(),
+            ),
+            call.head,
+        )
+        .into_pipeline_data())
+    }
+}

crates/nu-command/src/strings/format/mod.rs

@@ -1,7 +1,9 @@
 mod date;
 mod duration;
 mod filesize;
+mod format_;
 
-pub use self::filesize::FormatFilesize;
 pub use date::FormatDate;
 pub use duration::FormatDuration;
+pub use filesize::FormatFilesize;
+pub use format_::Format;