Add Support for Partial Completions (#3432)

This commit adds a conditional event handler that inserts the next word of the
hint text when the user presses control and right arrow.

Cargo.lock

@@ -1686,6 +1686,16 @@ dependencies = [
  "instant",
 ]
 
+[[package]]
+name = "fd-lock"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0010f02effd88c702318c5dde0463206be67495d0b4d906ba7c0a8f166cc7f06"
+dependencies = [
+ "libc",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "filesize"
 version = "0.2.0"
@@ -1766,16 +1776,6 @@ dependencies = [
  "percent-encoding 2.1.0",
 ]
 
-[[package]]
-name = "fs2"
-version = "0.4.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9564fc758e15025b46aa6643b1b77d047d1a56a1aea6e01002ac0c7026876213"
-dependencies = [
- "libc",
- "winapi 0.3.9",
-]
-
 [[package]]
 name = "fs_extra"
 version = "1.2.0"
@@ -5349,13 +5349,14 @@ checksum = "cb5d2a036dc6d2d8fd16fde3498b04306e29bd193bf306a57427019b823d5acd"
 [[package]]
 name = "rustyline"
 version = "8.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
+source = "git+https://github.com/kkawakam/rustyline.git#795867591dc72c2be172af45aabd1c6ecd579225"
-checksum = "b9e1b597fcd1eeb1d6b25b493538e5aa19629eb08932184b85fef931ba87e893"
 dependencies = [
  "bitflags",
  "cfg-if 1.0.0",
+ "clipboard-win",
  "dirs-next",
- "fs2",
+ "error-code",
+ "fd-lock",
  "libc",
  "log 0.4.14",
  "memchr",

crates/nu-cli/Cargo.toml

@@ -76,7 +76,7 @@ rayon = "1.5.0"
 regex = "1.4.3"
 roxmltree = "0.14.0"
 rust-embed = "5.9.0"
-rustyline = { version = "8.0.0", optional = true }
+rustyline = { git = "https://github.com/kkawakam/rustyline.git", optional = true }
 serde = { version = "1.0.123", features = ["derive"] }
 serde_bytes = "0.11.5"
 serde_ini = "0.2.0"

crates/nu-cli/src/line_editor.rs

@@ -19,7 +19,8 @@ use rustyline::{
     config::Configurer,
     config::{ColorMode, CompletionType, Config},
     error::ReadlineError,
-    At, Cmd, Editor, Movement, Word,
+    line_buffer::LineBuffer,
+    At, Cmd, ConditionalEventHandler, Editor, EventHandler, Movement, Word,
 };
 
 #[cfg(feature = "rustyline-support")]
@@ -36,6 +37,34 @@ pub fn convert_rustyline_result_to_string(input: Result<String, ReadlineError>)
     }
 }
 
+#[derive(Clone)]
+#[cfg(feature = "rustyline-support")]
+struct PartialCompleteHintHandler;
+
+#[cfg(feature = "rustyline-support")]
+impl ConditionalEventHandler for PartialCompleteHintHandler {
+    fn handle(
+        &self,
+        _evt: &rustyline::Event,
+        _n: rustyline::RepeatCount,
+        _positive: bool,
+        ctx: &rustyline::EventContext,
+    ) -> Option<Cmd> {
+        Some(match ctx.hint_text() {
+            Some(hint_text) if ctx.pos() == ctx.line().len() => {
+                let mut line_buffer = LineBuffer::with_capacity(hint_text.len());
+                line_buffer.update(hint_text, 0);
+                line_buffer.move_to_next_word(At::AfterEnd, Word::Vi, 1);
+
+                let text = hint_text[0..line_buffer.pos()].to_string();
+
+                Cmd::Insert(1, text)
+            }
+            _ => Cmd::Move(Movement::ForwardWord(1, At::AfterEnd, Word::Vi)),
+        })
+    }
+}
+
 #[cfg(feature = "rustyline-support")]
 pub fn default_rustyline_editor_configuration() -> Editor<Helper> {
     #[cfg(windows)]
@@ -56,7 +85,7 @@ pub fn default_rustyline_editor_configuration() -> Editor<Helper> {
     );
     rl.bind_sequence(
         convert_keyevent(KeyEvent::ControlRight),
-        Cmd::Move(Movement::ForwardWord(1, At::AfterEnd, Word::Vi)),
+        EventHandler::Conditional(Box::new(PartialCompleteHintHandler)),
     );
 
     // workaround for multiline-paste hang in rustyline (see https://github.com/kkawakam/rustyline/issues/202)

crates/nu-command/Cargo.toml

@@ -74,7 +74,7 @@ rayon = "1.5.0"
 regex = "1.4.3"
 roxmltree = "0.14.0"
 rust-embed = "5.9.0"
-rustyline = { version = "8.0.0", optional = true }
+rustyline = { git = "https://github.com/kkawakam/rustyline.git", optional = true }
 serde = { version = "1.0.123", features = ["derive"] }
 serde_bytes = "0.11.5"
 serde_ini = "0.2.0"