Add Source::{VariableValue, Other}

yash-syntax/CHANGELOG.md

@@ -20,6 +20,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   struct is renamed to `syntax::BracedParam`.
 - The `parser::SyntaxError::InvalidParam` variant is added, which is returned
   when a parameter expansion has an invalid name.
+- The `source::Source` enum is extended with new variants `VariableValue` and
+  `Other`.
 
 ### Changed
 

yash-syntax/src/source.rs

@@ -82,6 +82,18 @@ pub enum Source {
         /// Location of the simple command that has set this trap command
         origin: Location,
     },
+
+    /// Value of a variable
+    VariableValue {
+        /// Variable name
+        name: String,
+    },
+
+    /// Other source
+    Other {
+        /// Label that describes the source
+        label: String,
+    },
     // TODO More Source types
 }
 
@@ -159,6 +171,8 @@ impl Source {
             Eval { .. } => "<eval>",
             DotScript { name, .. } => name,
             Trap { condition, .. } => condition,
+            VariableValue { name } => name,
+            Other { label } => label,
         }
     }
 }

yash-syntax/src/source/pretty.rs

@@ -143,7 +143,13 @@ impl super::Source {
     pub fn complement_annotations<'a, 's: 'a, T: Extend<Annotation<'a>>>(&'s self, result: &mut T) {
         use super::Source::*;
         match self {
-            Unknown | Stdin | CommandString | CommandFile { .. } => (),
+            Unknown
+            | Stdin
+            | CommandString
+            | CommandFile { .. }
+            | VariableValue { .. }
+            | Other { .. } => (),
+
             CommandSubst { original } => {
                 // TODO Use Extend::extend_one
                 result.extend(std::iter::once(Annotation::new(