Added smallvec feature for inlining single completions

Cargo.toml

@@ -17,6 +17,8 @@ atty = "0.2"
 ui = { package = "discourse-ui", path = "./discourse-ui" }
 macros = { package = "discourse-macros", path = "./discourse-macros" }
 
+smallvec = { version = "1.6", optional = true }
+
 [dev-dependencies]
 trybuild = { version = "1.0.42", features = ["diff"] }
 # remove color printing since it messes with the snapshot's colours
@@ -29,6 +31,6 @@ regex = "1.5"           # examples/prompt_module.rs
 fuzzy-matcher = "0.3"   # examples/file.rs
 
 [features]
-default = ["crossterm"]
+default = ["crossterm", "smallvec"]
 crossterm = ["ui/crossterm"]
 termion = ["ui/termion"]

examples/file.rs

@@ -2,7 +2,9 @@ use std::path::Path;
 
 use fuzzy_matcher::{skim::SkimMatcherV2, FuzzyMatcher};
 
-fn auto_complete(p: String) -> Vec<String> {
+use discourse::question::Completions;
+
+fn auto_complete(p: String) -> Completions<String> {
     let current: &Path = p.as_ref();
     let (mut dir, last) = if p.ends_with('/') {
         (current, "")
@@ -19,7 +21,7 @@ fn auto_complete(p: String) -> Vec<String> {
         dir = ".".as_ref();
     }
 
-    let mut files: Vec<_> = match dir.read_dir() {
+    let mut files: Completions<_> = match dir.read_dir() {
         Ok(files) => files
             .flatten()
             .flat_map(|file| {
@@ -32,11 +34,13 @@ fn auto_complete(p: String) -> Vec<String> {
                 }
             })
             .collect(),
-        Err(_) => return vec![p],
+        Err(_) => {
+            return Completions::from([p]);
+        }
     };
 
     if files.is_empty() {
-        return vec![p];
+        Completions::from([p])
     } else {
         let fuzzer = SkimMatcherV2::default();
         files.sort_by_cached_key(|file| fuzzer.fuzzy_match(file, last).unwrap_or(i64::MAX));

src/question/input.rs

@@ -6,7 +6,7 @@ use ui::{
     widgets, Prompt, Validation, Widget,
 };
 
-use super::{AutoComplete, ChoiceList, Filter, Options, Transform, Validate};
+use super::{AutoComplete, ChoiceList, Completions, Filter, Options, Transform, Validate};
 use crate::{Answer, Answers};
 
 #[derive(Debug, Default)]
@@ -269,7 +269,7 @@ mod tests {
             (
                 Input {
                     auto_complete: AutoComplete::Sync(Box::new(|s, _| {
-                        let mut completions: Vec<_> = ('a'..='d')
+                        let mut completions: Completions<_> = ('a'..='d')
                             .map(|c| {
                                 let mut s = s.clone();
                                 s.push(c);

src/question/mod.rs

@@ -210,8 +210,13 @@ macro_rules! handler {
     };
 }
 
+#[cfg(feature = "smallvec")]
+pub type Completions<T> = smallvec::SmallVec<[T; 1]>;
+#[cfg(not(feature = "smallvec"))]
+pub type Completions<T> = Vec<T>;
+
 handler!(Filter, FnOnce(T, &Answers) -> T);
-handler!(AutoComplete, FnMut(T, &Answers) -> Vec<T>);
+handler!(AutoComplete, FnMut(T, &Answers) -> Completions<T>);
 handler!(Validate, ?Sized FnMut(&T, &Answers) -> Result<(), String>);
 handler!(ValidateByVal, FnMut(T, &Answers) -> Result<(), String>);
 handler!(Transform, ?Sized FnOnce(&T, &Answers, &mut dyn Backend) -> error::Result<()>);
@@ -240,7 +245,7 @@ macro_rules! impl_auto_complete_builder {
     ($t:ty; $inner:ident) => {
         pub fn auto_complete<F>(mut self, auto_complete: F) -> Self
         where
-            F: FnMut($t, &crate::Answers) -> Vec<$t> + 'a,
+            F: FnMut($t, &crate::Answers) -> Completions<$t> + 'a,
         {
             self.$inner.auto_complete =
                 crate::question::AutoComplete::Sync(Box::new(auto_complete));

tests/input.rs

@@ -1,4 +1,4 @@
-use discourse::{Answer, Question};
+use discourse::{question::Completions, Answer, Question};
 use ui::{
     events::{KeyCode, TestEvents},
     style::Color,
@@ -107,7 +107,7 @@ fn test_auto_complete() {
     let prompt = Question::input("name")
         .message("message")
         .auto_complete(|s, _| {
-            let mut completions: Vec<_> = ('g'..='j')
+            let mut completions: Completions<_> = ('g'..='j')
                 .map(|c| {
                     let mut s = s.clone();
                     s.push(c);