Abstract the implementation of Shape.

src/shape.rs

@@ -1,7 +1,7 @@
 use crate::{Error, Result};
 
 #[derive(Clone, PartialEq, Eq)]
-pub struct Shape(pub(crate) Vec<usize>);
+pub struct Shape(Vec<usize>);
 
 impl std::fmt::Debug for Shape {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -63,6 +63,12 @@ impl From<(usize, usize, usize)> for Shape {
     }
 }
 
+impl From<Vec<usize>> for Shape {
+    fn from(dims: Vec<usize>) -> Self {
+        Self(dims)
+    }
+}
+
 macro_rules! extract_dims {
     ($fn_name:ident, $cnt:tt, $dims:expr, $out_type:ty) => {
         pub fn $fn_name(&self) -> Result<$out_type> {
@@ -142,6 +148,11 @@ impl Shape {
         }
         true
     }
+
+    pub fn extend(mut self, additional_dims: &[usize]) -> Self {
+        self.0.extend(additional_dims);
+        self
+    }
 }
 
 #[cfg(test)]