feat(commands): add `selection` variable expansion

book/src/command-line.md

@@ -48,6 +48,7 @@ The following variables are supported:
 | `buffer_name` | The relative path of the currently focused document. `[scratch]` is expanded instead for scratch buffers. |
 | `line_ending` | A string containing the line ending of the currently focused document. For example on Unix systems this is usually a line-feed character (`\n`) but on Windows systems this may be a carriage-return plus a line-feed (`\r\n`). The line ending kind of the currently focused document can be inspected with the `:line-ending` command. |
 | `language` | A string containing the language name of the currently focused document.|
+| `selection` | A string containing the primary selection of the currently focused document. |
 
 Aside from editor variables, the following expansions may be used:
 

helix-view/src/expansion.rs

@@ -35,6 +35,8 @@ pub enum Variable {
     LineEnding,
     // The name of current buffers language as set in `languages.toml`
     Language,
+    // Primary selection
+    Selection,
 }
 
 impl Variable {
@@ -44,6 +46,7 @@ impl Variable {
         Self::BufferName,
         Self::LineEnding,
         Self::Language,
+        Self::Selection,
     ];
 
     pub const fn as_str(&self) -> &'static str {
@@ -53,6 +56,7 @@ impl Variable {
             Self::BufferName => "buffer_name",
             Self::LineEnding => "line_ending",
             Self::Language => "language",
+            Self::Selection => "selection",
         }
     }
 
@@ -63,6 +67,7 @@ impl Variable {
             "buffer_name" => Some(Self::BufferName),
             "line_ending" => Some(Self::LineEnding),
             "language" => Some(Self::Language),
+            "selection" => Some(Self::Selection),
             _ => None,
         }
     }
@@ -224,5 +229,8 @@ fn expand_variable(editor: &Editor, variable: Variable) -> Result<Cow<'static, s
             Some(lang) => Cow::Owned(lang.to_owned()),
             None => Cow::Borrowed("text"),
         }),
+        Variable::Selection => Ok(Cow::Owned(
+            doc.selection(view.id).primary().fragment(text).to_string(),
+        )),
     }
 }