feat: Add Visible Aliases for PossibleValue

Before this change, it was not possible to have *visible* aliases
for PossibleValues, all aliases were hidden in help output. This
change adds a new API for adding visible aliases and modifies the
help generation scheme to display these visible aliases.

Author: naftulikay

clap_builder/src/builder/possible_value.rs

@@ -1,3 +1,5 @@
+use anstyle::Style;
+
 use crate::builder::IntoResettable;
 use crate::builder::Str;
 use crate::builder::StyledStr;
@@ -37,6 +39,7 @@ pub struct PossibleValue {
     name: Str,
     help: Option<StyledStr>,
     aliases: Vec<Str>, // (name, visible)
+    visible_aliases: Vec<Str>,
     hide: bool,
 }
 
@@ -130,6 +133,20 @@ impl PossibleValue {
         self
     }
 
+    /// Add a _visible_ alias to this [PossibleValue].
+    ///
+    /// Unlike [PossibleValue::alias], these aliases will show in help output.
+    #[must_use]
+    pub fn visible_alias(mut self, name: impl IntoResettable<Str>) -> Self {
+        if let Some(name) = name.into_resettable().into_option() {
+            self.visible_aliases.push(name);
+        } else {
+            self.visible_aliases.clear();
+        }
+
+        self
+    }
+
     /// Sets multiple *hidden* aliases for this argument value.
     ///
     /// # Examples
@@ -146,6 +163,16 @@ impl PossibleValue {
         self.aliases.extend(names.into_iter().map(|a| a.into()));
         self
     }
+
+    /// Add multiple _visible_ aliases to this [PossibleValue].
+    ///
+    /// Unlike [PossibleValue::aliases], these aliases will show in help output.
+    #[must_use]
+    pub fn visible_aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
+        self.visible_aliases
+            .extend(names.into_iter().map(|a| a.into()));
+        self
+    }
 }
 
 /// Reflection
@@ -156,6 +183,42 @@ impl PossibleValue {
         self.name.as_str()
     }
 
+    /// Get the visible aliases for this argument
+    pub fn get_visible_aliases(&self) -> &Vec<Str> {
+        &self.visible_aliases
+    }
+
+    /// Render help text for this [PossibleValue] with all of its visible aliases included.
+    ///
+    /// If there are no visible aliases, this will simply emit the formatted name, if there are visible aliases, these
+    /// will be appended like this: `name [aliases: a, b, c]`.
+    pub fn render_help_prefix_long(&self, literal: &Style) -> String {
+        const ALIASES_PREFIX: &str = " [aliases: ";
+        const ALIASES_POSTFIX: &str = "]";
+        const ALIASES_JOINER: &str = ", ";
+
+        let name = self.get_name();
+        let aliases = if self.get_visible_aliases().is_empty() {
+            "".to_string()
+        } else {
+            // [aliases: a, b, c]
+            format!(
+                "{ALIASES_PREFIX}{}{ALIASES_POSTFIX}",
+                self.get_visible_aliases()
+                    .iter()
+                    .map(|s| { format!("{}{s}{}", literal.render(), literal.render_reset()) })
+                    .collect::<Vec<_>>()
+                    .join(ALIASES_JOINER)
+            )
+        };
+
+        format!(
+            "{}{name}{}{aliases}",
+            literal.render(),
+            literal.render_reset()
+        )
+    }
+
     /// Get the help specified for this argument, if any
     #[inline]
     pub fn get_help(&self) -> Option<&StyledStr> {
@@ -192,7 +255,9 @@ impl PossibleValue {
     ///
     /// Namely the name and all aliases.
     pub fn get_name_and_aliases(&self) -> impl Iterator<Item = &str> + '_ {
-        std::iter::once(self.get_name()).chain(self.aliases.iter().map(|s| s.as_str()))
+        std::iter::once(self.get_name())
+            .chain(self.aliases.iter().map(|s| s.as_str()))
+            .chain(self.visible_aliases.iter().map(|s| s.as_str()))
     }
 
     /// Tests if the value is valid for this argument value

clap_builder/src/output/help_template.rs

@@ -8,12 +8,12 @@ use std::borrow::Cow;
 use std::cmp;
 use std::usize;
 
+use crate::builder::{Arg, Command};
 // Internal
 use crate::builder::PossibleValue;
 use crate::builder::Str;
 use crate::builder::StyledStr;
 use crate::builder::Styles;
-use crate::builder::{Arg, Command};
 use crate::output::display_width;
 use crate::output::wrap;
 use crate::output::Usage;
@@ -689,10 +689,12 @@ impl<'cmd, 'writer> HelpTemplate<'cmd, 'writer> {
                 let possible_vals = arg.get_possible_values();
                 if !possible_vals.is_empty() {
                     debug!("HelpTemplate::help: Found possible vals...{possible_vals:?}");
+
+                    // FIXME
                     let longest = possible_vals
                         .iter()
                         .filter(|f| !f.is_hide_set())
-                        .map(|f| display_width(f.get_name()))
+                        .map(|f| display_width(f.render_help_prefix_long(literal).as_str()))
                         .max()
                         .expect("Only called with possible value");
 
@@ -705,19 +707,15 @@ impl<'cmd, 'writer> HelpTemplate<'cmd, 'writer> {
                     }
                     self.writer.push_str("Possible values:");
                     for pv in possible_vals.iter().filter(|pv| !pv.is_hide_set()) {
-                        let name = pv.get_name();
+                        let prefix = pv.render_help_prefix_long(literal);
 
                         let mut descr = StyledStr::new();
-                        let _ = write!(
-                            &mut descr,
-                            "{}{name}{}",
-                            literal.render(),
-                            literal.render_reset()
-                        );
+
+                        let _ = write!(&mut descr, "{prefix}",);
                         if let Some(help) = pv.get_help() {
                             debug!("HelpTemplate::help: Possible Value help");
                             // To align help messages
-                            let padding = longest - display_width(name);
+                            let padding = longest - display_width(prefix.as_str());
                             let _ = write!(&mut descr, ": {:padding$}", "");
                             descr.push_styled(help);
                         }
@@ -848,9 +846,15 @@ impl<'cmd, 'writer> HelpTemplate<'cmd, 'writer> {
             if !possible_vals.is_empty() {
                 debug!("HelpTemplate::spec_vals: Found possible vals...{possible_vals:?}");
 
+                // FIXME here is where possible values are formatted in short form, should be a list with no difference
+                //       between possible value names and visible aliases
                 let pvs = possible_vals
                     .iter()
-                    .filter_map(PossibleValue::get_visible_quoted_name)
+                    .filter(|v| !v.is_hide_set())
+                    .flat_map(|v| {
+                        std::iter::once(v.get_name())
+                            .chain(v.get_visible_aliases().iter().map(|s| s.as_str()))
+                    })
                     .collect::<Vec<_>>()
                     .join(", ");