Add 'interact_text_opt' and 'interact_text_on_opt' for 'Input' prompts

src/prompts/input.rs

@@ -1,6 +1,5 @@
 use std::{
     cmp::Ordering,
-    fmt::Debug,
     io, iter,
     str::FromStr,
     sync::{Arc, Mutex},
@@ -281,20 +280,46 @@ where
 impl<T> Input<'_, T>
 where
     T: Clone + ToString + FromStr,
-    <T as FromStr>::Err: Debug + ToString,
+    <T as FromStr>::Err: ToString,
 {
     /// Enables the user to enter a printable ascii sequence and returns the result.
     ///
     /// Its difference from [`interact`](Self::interact) is that it only allows ascii characters for string,
     /// while [`interact`](Self::interact) allows virtually any character to be used e.g arrow keys.
     ///
     /// The dialog is rendered on stderr.
+    /// This unlike [`interact_text_opt`](Self::interact_text_opt) does not allow to quit with 'Esc'
     pub fn interact_text(self) -> Result<T> {
         self.interact_text_on(&Term::stderr())
     }
 
+    /// Enables the user to enter a printable ascii sequence and returns the result.
+    ///
+    /// Its difference from [`interact_opt`](Self::interact_opt) is that it only allows ascii characters for string,
+    /// while [`interact_opt`](Self::interact_opt) allows virtually any character to be used e.g arrow keys.
+    ///
+    /// The dialog is rendered on stderr.
+    /// Result contains `Some(T)` if user hit 'Enter' or `None` if user cancelled with 'Esc'
+    #[inline]
+    pub fn interact_text_opt(self) -> Result<Option<T>> {
+        self.interact_text_on_opt(&Term::stderr())
+    }
+
     /// Like [`interact_text`](Self::interact_text) but allows a specific terminal to be set.
-    pub fn interact_text_on(mut self, term: &Term) -> Result<T> {
+    #[inline]
+    pub fn interact_text_on(self, term: &Term) -> Result<T> {
+        Ok(self
+            ._interact_text_on(term, false)?
+            .ok_or_else(|| io::Error::new(io::ErrorKind::Other, "Quit not allowed in this case"))?)
+    }
+
+    /// Like [`interact_text_opt`](Self::interact_text_opt) but allows a specific terminal to be set.
+    #[inline]
+    pub fn interact_text_on_opt(self, term: &Term) -> Result<Option<T>> {
+        self._interact_text_on(term, true)
+    }
+
+    fn _interact_text_on(mut self, term: &Term, allow_quit: bool) -> Result<Option<T>> {
         if !term.is_term() {
             return Err(io::Error::new(io::ErrorKind::NotConnected, "not a terminal").into());
         }
@@ -313,11 +338,6 @@ where
                 },
             )?;
 
-            // Read input by keystroke so that we can suppress ascii control characters
-            if !term.features().is_attended() {
-                return Ok("".to_owned().parse::<T>().unwrap());
-            }
-
             let mut chars: Vec<char> = Vec::new();
             let mut position = 0;
             #[cfg(feature = "history")]
@@ -332,6 +352,12 @@ where
 
             loop {
                 match term.read_key()? {
+                    Key::Escape if allow_quit => {
+                        render.clear()?;
+                        term.flush()?;
+                        term.show_cursor()?;
+                        return Ok(None);
+                    }
                     Key::Backspace if position > 0 => {
                         position -= 1;
                         chars.remove(position);
@@ -591,7 +617,7 @@ where
                         render.input_prompt_selection(&self.prompt, &default.to_string())?;
                     }
                     term.flush()?;
-                    return Ok(default.clone());
+                    return Ok(Some(default.clone()));
                 } else if !self.permit_empty {
                     continue;
                 }
@@ -620,7 +646,7 @@ where
                     }
                     term.flush()?;
 
-                    return Ok(value);
+                    return Ok(Some(value));
                 }
                 Err(err) => {
                     render.error(&err.to_string())?;
@@ -629,13 +655,7 @@ where
             }
         }
     }
-}
 
-impl<T> Input<'_, T>
-where
-    T: Clone + ToString + FromStr,
-    <T as FromStr>::Err: ToString,
-{
     /// Enables user interaction and returns the result.
     ///
     /// Allows any characters as input, including e.g arrow keys.