harmonize partial strings with complete strings (#276), make Addr a copyable type

src/prolog/machine/raw_block.rs

@@ -5,7 +5,7 @@ use std::mem;
 use std::ptr;
 
 pub(crate) trait RawBlockTraits {
-    fn init_size() -> usize;    
+    fn init_size() -> usize;
     fn align() -> usize;
 
     #[inline]
@@ -36,20 +36,6 @@ impl<T: RawBlockTraits> RawBlock<T> {
         block
     }
 
-    pub(crate)
-    fn with_capacity(cap: usize) -> Self {
-        let mut block = RawBlock { size: 0,
-                                   base: ptr::null(),
-                                   top: ptr::null(),
-                                   _marker: PhantomData };
-
-        unsafe {
-            block.init_at_size(cap);
-        }
-
-        block
-    }
-
     unsafe fn init_at_size(&mut self, cap: usize) {
         let layout = alloc::Layout::from_size_align_unchecked(cap, T::align());
 
@@ -86,7 +72,6 @@ impl<T: RawBlockTraits> RawBlock<T> {
         mem::replace(self, Self::empty_block())
     }
 
-
     #[inline]
     fn free_space(&self) -> usize {
         debug_assert!(self.top >= self.base,