From e7f08cb21d6b3669e1df6b16684b1832f02d9ff2 Mon Sep 17 00:00:00 2001
From: Michael Nitschinger <michael@nitschinger.at>
Date: Thu, 14 May 2020 02:35:22 +0200
Subject: [PATCH] Allow external binary to register custom commands. (#1780)

This changeset contains everything that a separate binary needs to
register its own commands (including the new help function). It is
very possible that this commit misses other pub use exports, but
the contained ones work for our use cases so far.
---
 crates/nu-cli/src/cli.rs           | 9 +++++----
 crates/nu-cli/src/commands/help.rs | 2 +-
 crates/nu-cli/src/lib.rs           | 6 ++++++
 src/main.rs                        | 6 +++++-
 4 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/crates/nu-cli/src/cli.rs b/crates/nu-cli/src/cli.rs
index 65f42d9158..65abe93a70 100644
--- a/crates/nu-cli/src/cli.rs
+++ b/crates/nu-cli/src/cli.rs
@@ -8,6 +8,7 @@ use crate::context::Context;
 use crate::git::current_branch;
 use crate::path::canonicalize;
 use crate::prelude::*;
+use crate::EnvironmentSyncer;
 use futures_codec::FramedRead;
 
 use nu_errors::ShellError;
@@ -482,15 +483,15 @@ pub async fn run_pipeline_standalone(
 }
 
 /// The entry point for the CLI. Will register all known internal commands, load experimental commands, load plugins, then prepare the prompt and line reader for input.
-pub async fn cli() -> Result<(), Box<dyn Error>> {
+pub async fn cli(
+    mut syncer: EnvironmentSyncer,
+    mut context: Context,
+) -> Result<(), Box<dyn Error>> {
     #[cfg(windows)]
     const DEFAULT_COMPLETION_MODE: CompletionType = CompletionType::Circular;
     #[cfg(not(windows))]
     const DEFAULT_COMPLETION_MODE: CompletionType = CompletionType::List;
 
-    let mut syncer = crate::EnvironmentSyncer::new();
-    let mut context = create_default_context(&mut syncer, true)?;
-
     let _ = load_plugins(&mut context);
 
     let config = Config::builder().color_mode(ColorMode::Forced).build();
diff --git a/crates/nu-cli/src/commands/help.rs b/crates/nu-cli/src/commands/help.rs
index 23c5eba6fe..9f7076fe70 100644
--- a/crates/nu-cli/src/commands/help.rs
+++ b/crates/nu-cli/src/commands/help.rs
@@ -131,7 +131,7 @@ You can also learn more at https://www.nushell.sh/book/"#;
 }
 
 #[allow(clippy::cognitive_complexity)]
-pub(crate) fn get_help(
+pub fn get_help(
     cmd: &dyn WholeStreamCommand,
     registry: &CommandRegistry,
 ) -> impl Into<OutputStream> {
diff --git a/crates/nu-cli/src/lib.rs b/crates/nu-cli/src/lib.rs
index 6c6ce62d8c..3b50b353aa 100644
--- a/crates/nu-cli/src/lib.rs
+++ b/crates/nu-cli/src/lib.rs
@@ -31,11 +31,17 @@ mod utils;
 pub use crate::cli::{
     cli, create_default_context, load_plugins, run_pipeline_standalone, run_vec_of_pipelines,
 };
+pub use crate::commands::command::{
+    whole_stream_command, CommandArgs, EvaluatedWholeStreamCommandArgs, WholeStreamCommand,
+};
+pub use crate::commands::help::get_help;
+pub use crate::context::CommandRegistry;
 pub use crate::data::dict::TaggedListBuilder;
 pub use crate::data::primitive;
 pub use crate::data::value;
 pub use crate::env::environment_syncer::EnvironmentSyncer;
 pub use crate::env::host::BasicHost;
+pub use crate::stream::OutputStream;
 pub use nu_value_ext::ValueExt;
 pub use num_traits::cast::ToPrimitive;
 
diff --git a/src/main.rs b/src/main.rs
index 58ac6d5515..2ccfcbee11 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,6 @@
 use clap::{App, Arg};
 use log::LevelFilter;
+use nu_cli::{create_default_context, EnvironmentSyncer};
 use std::error::Error;
 use std::fs::File;
 use std::io::{prelude::*, BufReader};
@@ -128,7 +129,10 @@ fn main() -> Result<(), Box<dyn Error>> {
                 "Welcome to Nushell {} (type 'help' for more info)",
                 clap::crate_version!()
             );
-            futures::executor::block_on(nu_cli::cli())?;
+
+            let mut syncer = EnvironmentSyncer::new();
+            let context = create_default_context(&mut syncer, true)?;
+            futures::executor::block_on(nu_cli::cli(syncer, context))?;
         }
     }