feat: allow clearing namespace, version, sub path, and qualifiers

src/purl.rs

@@ -175,6 +175,12 @@ impl<'a> PackageUrl<'a> {
         self
     }
 
+    /// Clear the namespace
+    pub fn without_namespace(&mut self) -> &mut Self {
+        self.namespace = None;
+        self
+    }
+
     /// Assign a version to the package.
     pub fn with_version<V>(&mut self, version: V) -> &mut Self
     where
@@ -184,6 +190,12 @@ impl<'a> PackageUrl<'a> {
         self
     }
 
+    /// Clear the version
+    pub fn without_version(&mut self) -> &mut Self {
+        self.version = None;
+        self
+    }
+
     /// Assign a subpath to the package.
     ///
     /// Subpaths must not contain empty, local ('.') or parent ('..') segments,
@@ -202,6 +214,18 @@ impl<'a> PackageUrl<'a> {
         Ok(self)
     }
 
+    /// Clear the subpath
+    pub fn without_subpath(&mut self) -> &mut Self {
+        self.subpath = None;
+        self
+    }
+
+    /// Clear qualifiers
+    pub fn clear_qualifiers(&mut self) -> &mut Self {
+        self.qualifiers.clear();
+        self
+    }
+
     /// Add a qualifier to the package.
     pub fn add_qualifier<K, V>(&mut self, key: K, value: V) -> Result<&mut Self>
     where