Merge pull request #142 from yvan-sraka/completion-feature

Implement a first proposal of a completion feature

Author: pksunkara

Cargo.toml

@@ -21,6 +21,7 @@ editor = ["tempfile"]
 fuzzy-select = ["fuzzy-matcher"]
 history = []
 password = ["zeroize"]
+completion = []
 
 [dependencies]
 console = "0.15.0"
@@ -44,3 +45,7 @@ required-features = ["fuzzy-select"]
 [[example]]
 name = "history"
 required-features = ["history"]
+
+[[example]]
+name = "completion"
+required-features = ["completion"]

examples/completion.rs

@@ -0,0 +1,40 @@
+use dialoguer::{theme::ColorfulTheme, Completion, Input};
+
+fn main() -> Result<(), std::io::Error> {
+    println!("Use the Right arrow or Tab to complete your command");
+    let completion = MyCompletion::default();
+    Input::<String>::with_theme(&ColorfulTheme::default())
+        .with_prompt("dialoguer")
+        .completion_with(&completion)
+        .interact_text()?;
+    Ok(())
+}
+
+struct MyCompletion {
+    options: Vec<String>,
+}
+
+impl Default for MyCompletion {
+    fn default() -> Self {
+        MyCompletion {
+            options: vec![
+                "orange".to_string(),
+                "apple".to_string(),
+                "banana".to_string(),
+            ],
+        }
+    }
+}
+
+impl Completion for MyCompletion {
+    /// Simple completion implementation based on substring
+    fn get(&self, input: &str) -> Option<String> {
+        let s = input.to_string();
+        let ss: Vec<&String> = self.options.iter().filter(|x| s == x[..s.len()]).collect();
+        if ss.len() == 1 {
+            Some(ss[0].to_string())
+        } else {
+            None
+        }
+    }
+}

src/completion.rs

@@ -0,0 +1,4 @@
+/// Trait for completion handling.
+pub trait Completion {
+    fn get(&self, input: &str) -> Option<String>;
+}

src/lib.rs

@@ -18,6 +18,8 @@
 //! * Other kind of prompts
 //! * Editor launching
 
+#[cfg(feature = "completion")]
+pub use completion::Completion;
 pub use console;
 #[cfg(feature = "editor")]
 pub use edit::Editor;
@@ -35,6 +37,8 @@ pub use prompts::fuzzy_select::FuzzySelect;
 #[cfg(feature = "password")]
 pub use prompts::password::Password;
 
+#[cfg(feature = "completion")]
+mod completion;
 #[cfg(feature = "editor")]
 mod edit;
 #[cfg(feature = "history")]

src/prompts/input.rs

@@ -1,5 +1,7 @@
 use std::{fmt::Debug, io, iter, str::FromStr};
 
+#[cfg(feature = "completion")]
+use crate::completion::Completion;
 #[cfg(feature = "history")]
 use crate::history::History;
 use crate::{
@@ -45,6 +47,8 @@ pub struct Input<'a, T> {
     validator: Option<Box<dyn FnMut(&T) -> Option<String> + 'a>>,
     #[cfg(feature = "history")]
     history: Option<&'a mut dyn History<T>>,
+    #[cfg(feature = "completion")]
+    completion: Option<&'a dyn Completion>,
 }
 
 impl<T> Default for Input<'static, T> {
@@ -114,6 +118,8 @@ impl<'a, T> Input<'a, T> {
             validator: None,
             #[cfg(feature = "history")]
             history: None,
+            #[cfg(feature = "completion")]
+            completion: None,
         }
     }
 
@@ -166,6 +172,16 @@ impl<'a, T> Input<'a, T> {
         self.history = Some(history);
         self
     }
+
+    /// Enable completion
+    #[cfg(feature = "completion")]
+    pub fn completion_with<C>(&mut self, completion: &'a C) -> &mut Self
+    where
+        C: Completion,
+    {
+        self.completion = Some(completion);
+        self
+    }
 }
 
 impl<'a, T> Input<'a, T>
@@ -297,6 +313,23 @@ where
                         position += 1;
                         term.flush()?;
                     }
+                    #[cfg(feature = "completion")]
+                    Key::ArrowRight | Key::Tab => {
+                        if let Some(completion) = &self.completion {
+                            let input: String = chars.clone().into_iter().collect();
+                            if let Some(x) = completion.get(&input) {
+                                term.clear_chars(chars.len())?;
+                                chars.clear();
+                                position = 0;
+                                for ch in x.chars() {
+                                    chars.insert(position, ch);
+                                    position += 1;
+                                }
+                                term.write_str(&x)?;
+                                term.flush()?;
+                            }
+                        }
+                    }
                     #[cfg(feature = "history")]
                     Key::ArrowUp => {
                         if let Some(history) = &self.history {