From ff63e410cec670ec7f5f2b1205dab34c6f1f305e Mon Sep 17 00:00:00 2001
From: neeldug <5161147+neeldug@users.noreply.github.com>
Date: Thu, 10 Aug 2023 22:54:19 +0100
Subject: [PATCH] feat(Header): `Header::num_vars` implementation

---
 src/lib.rs   | 25 +++++++++++++++++++++++++
 src/scope.rs | 11 +++++++++++
 2 files changed, 36 insertions(+)

diff --git a/src/lib.rs b/src/lib.rs
index 5990e5b..67cad49 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -318,4 +318,29 @@ impl Header {
             _ => None,
         })
     }
+
+    /// Find the variable object at a specified path.
+    ///
+    /// ## Example
+    ///
+    /// ```rust
+    /// let mut parser = vcd::Parser::new(&b"
+    /// $scope module a $end
+    /// $var integer 32 y counter_b $end
+    /// $scope module b $end
+    /// $var integer 16 n0 counter $end
+    /// $upscope $end
+    /// $upscope $end
+    /// $enddefinitions $end
+    /// "[..]);
+    /// let header = parser.parse_header().unwrap();
+    /// let var_count = header.num_vars();
+    /// assert_eq!(var_count, 2);
+    /// ```
+    pub fn num_vars(&self) -> usize {
+        self.items
+            .iter()
+            .filter(|item| matches!(item, ScopeItem::Var(_) | ScopeItem::Scope(_)))
+            .fold(0, |acc, scope_item| acc + scope_item.num_vars())
+    }
 }
diff --git a/src/scope.rs b/src/scope.rs
index a7c641f..6c483ce 100644
--- a/src/scope.rs
+++ b/src/scope.rs
@@ -292,3 +292,14 @@ pub enum ScopeItem {
     /// `$comment` - Comment
     Comment(String),
 }
+
+impl ScopeItem {
+    /// Returns the number of variables in this scope item.
+    pub fn num_vars(&self) -> usize {
+        match self {
+            ScopeItem::Scope(s) => s.items.iter().map(ScopeItem::num_vars).sum(),
+            ScopeItem::Var(_) => 1,
+            ScopeItem::Comment(_) => 0,
+        }
+    }
+}