Move explore command out of nu-command deps (#9421)

# Description
For better parallel compilation, make sure that `nu-command` doesn't
depend on `nu-explore`.

Moves the `nu_protocol::Command` implementation into `nu-explore`. Adds
`nu_explore::add_explore_context()` which is used in `main.rs` to add
the `explore` command.

Minor improvement in compile time ~0.5 sec observed as `nu-command`
still blocks on `nu-cmd-lang` as well.

## `cargo build --timings` before


![grafik](https://github.com/nushell/nushell/assets/15833959/583aa56e-6a1e-47b9-ba00-6a86293a38db)

## `cargo build --timings` after


![grafik](https://github.com/nushell/nushell/assets/15833959/30687575-c1c8-4635-bcdd-7ce9488fcfff)


# User-Facing Changes
None

Cargo.lock

@@ -2656,6 +2656,7 @@ dependencies = [
  "nu-color-config",
  "nu-command",
  "nu-engine",
+ "nu-explore",
  "nu-json",
  "nu-parser",
  "nu-path",
@@ -2829,7 +2830,6 @@ dependencies = [
  "nu-cmd-lang",
  "nu-color-config",
  "nu-engine",
- "nu-explore",
  "nu-glob",
  "nu-json",
  "nu-parser",

Cargo.toml

@@ -51,6 +51,7 @@ nu-cmd-lang = { path = "./crates/nu-cmd-lang", version = "0.81.1" }
 nu-cmd-dataframe = { path = "./crates/nu-cmd-dataframe", version = "0.81.1", optional = true }
 nu-command = { path = "./crates/nu-command", version = "0.81.1" }
 nu-engine = { path = "./crates/nu-engine", version = "0.81.1" }
+nu-explore = { path = "./crates/nu-explore", version = "0.81.1" }
 nu-json = { path = "./crates/nu-json", version = "0.81.1" }
 nu-parser = { path = "./crates/nu-parser", version = "0.81.1" }
 nu-path = { path = "./crates/nu-path", version = "0.81.1" }

crates/nu-command/Cargo.toml

@@ -18,7 +18,6 @@ nu-cmd-dataframe = { path = "../nu-cmd-dataframe", version = "0.81.1", optional
 nu-cmd-extra = { path = "../nu-cmd-extra", version = "0.81.1", optional = true }
 nu-color-config = { path = "../nu-color-config", version = "0.81.1" }
 nu-engine = { path = "../nu-engine", version = "0.81.1" }
-nu-explore = { path = "../nu-explore", version = "0.81.1" }
 nu-glob = { path = "../nu-glob", version = "0.81.1" }
 nu-json = { path = "../nu-json", version = "0.81.1" }
 nu-parser = { path = "../nu-parser", version = "0.81.1" }

crates/nu-command/src/default_context.rs

@@ -311,7 +311,6 @@ pub fn create_default_context() -> EngineState {
         bind_command! {
             Griddle,
             Table,
-            Explore,
         };
 
         // Conversions

crates/nu-command/src/viewers/mod.rs

@@ -1,8 +1,6 @@
-mod explore;
 mod griddle;
 mod icons;
 mod table;
 
-pub use explore::Explore;
 pub use griddle::Griddle;
 pub use table::Table;

crates/nu-explore/src/default_context.rs

@@ -0,0 +1,17 @@
+use nu_protocol::engine::{EngineState, StateWorkingSet};
+
+use crate::explore::*;
+
+pub fn add_explore_context(mut engine_state: EngineState) -> EngineState {
+    let delta = {
+        let mut working_set = StateWorkingSet::new(&engine_state);
+        working_set.add_decl(Box::new(Explore));
+        working_set.render()
+    };
+
+    if let Err(err) = engine_state.merge_delta(delta) {
+        eprintln!("Error creating explore command context: {err:?}");
+    }
+
+    engine_state
+}

crates/nu-explore/src/explore.rs

@@ -1,12 +1,12 @@
+use crate::{
+    run_pager,
+    util::{create_lscolors, create_map, map_into_value},
+    PagerConfig, StyleConfig,
+};
 use ahash::HashMap;
 use nu_ansi_term::{Color, Style};
 use nu_color_config::{get_color_map, StyleComputer};
 use nu_engine::CallExt;
-use nu_explore::{
-    run_pager,
-    util::{create_map, map_into_value},
-    PagerConfig, StyleConfig,
-};
 use nu_protocol::{
     ast::Call,
     engine::{Command, EngineState, Stack},
@@ -82,7 +82,7 @@ impl Command for Explore {
 
         let style = style_from_config(&config);
 
-        let lscolors = nu_explore::util::create_lscolors(engine_state, stack);
+        let lscolors = create_lscolors(engine_state, stack);
 
         let mut config = PagerConfig::new(nu_config, &style_computer, &lscolors, config);
         config.style = style;

crates/nu-explore/src/lib.rs

@@ -1,9 +1,14 @@
 mod commands;
+mod default_context;
+mod explore;
 mod nu_common;
 mod pager;
 mod registry;
 mod views;
 
+pub use default_context::add_explore_context;
+pub use explore::Explore;
+
 use std::io;
 
 use commands::{
@@ -20,13 +25,13 @@ use registry::{Command, CommandRegistry};
 use terminal_size::{Height, Width};
 use views::{InformationView, Orientation, Preview, RecordView};
 
-pub use pager::{PagerConfig, StyleConfig};
+use pager::{PagerConfig, StyleConfig};
 
-pub mod util {
+mod util {
     pub use super::nu_common::{create_lscolors, create_map, map_into_value};
 }
 
-pub fn run_pager(
+fn run_pager(
     engine_state: &EngineState,
     stack: &mut Stack,
     ctrlc: CtrlC,
@@ -83,7 +88,7 @@ fn information_view() -> Option<Page> {
     Some(Page::new(InformationView, true))
 }
 
-pub fn create_command_registry() -> CommandRegistry {
+fn create_command_registry() -> CommandRegistry {
     let mut registry = CommandRegistry::new();
     create_commands(&mut registry);
     create_aliases(&mut registry);
@@ -101,7 +106,7 @@ pub fn create_command_registry() -> CommandRegistry {
     registry
 }
 
-pub fn create_commands(registry: &mut CommandRegistry) {
+fn create_commands(registry: &mut CommandRegistry) {
     registry.register_command_view(NuCmd::new(), false);
     registry.register_command_view(TableCmd::new(), false);
 
@@ -115,7 +120,7 @@ pub fn create_commands(registry: &mut CommandRegistry) {
     registry.register_command_reactive(TweakCmd::default());
 }
 
-pub fn create_aliases(registry: &mut CommandRegistry) {
+fn create_aliases(registry: &mut CommandRegistry) {
     registry.create_aliases("h", HelpCmd::NAME);
     registry.create_aliases("e", ExpandCmd::NAME);
     registry.create_aliases("q", QuitCmd::NAME);

src/main.rs

@@ -43,7 +43,8 @@ fn main() -> Result<()> {
 
     // Get initial current working directory.
     let init_cwd = get_init_cwd();
-    let mut engine_state = nu_cli::add_cli_context(create_default_context());
+    let mut engine_state =
+        nu_explore::add_explore_context(nu_cli::add_cli_context(create_default_context()));
 
     // Custom additions
     let delta = {