distinguish eq from structural_eq on strings

src/prolog/string_list.rs

@@ -1,5 +1,3 @@
-use prolog::tabled_rc::*;
-
 use std::cell::{Cell, Ref, RefCell};
 use std::cmp::Ordering;
 use std::hash::{Hash, Hasher};
@@ -17,25 +15,28 @@ impl Hash for StringListWrapper {
 // cursor is ignored if the double_quotes flag is set to atom
 #[derive(Clone)]
 pub struct StringList {
-    body: TabledRc<StringListWrapper>,
+    body: Rc<StringListWrapper>,
     cursor: usize, // use this to generate a chars() iterator on the fly,
                    // and skip over the first cursor chars.
     expandable: Rc<Cell<bool>>
 }
 
 impl Hash for StringList {
+    #[inline]    
     fn hash<H: Hasher>(&self, state: &mut H) {
         (self.borrow().as_str(), self.cursor, self.expandable.get()).hash(state);
     }
 }
 
 impl PartialOrd for StringList {
+    #[inline]    
     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
         Some(self.body.cmp(&other.body))
     }
 }
 
 impl Ord for StringList {
+    #[inline]
     fn cmp(&self, other: &Self) -> Ordering {
         if self.expandable.get() && !self.expandable.get() {
             Ordering::Greater
@@ -48,8 +49,9 @@ impl Ord for StringList {
 }
 
 impl PartialEq for StringList {
+    #[inline]
     fn eq(&self, other: &Self) -> bool {
-        self.borrow()[self.cursor ..] == other.borrow()[other.cursor ..] && self.expandable == other.expandable
+        Rc::ptr_eq(&self.body, &other.body)
     }
 }
 
@@ -57,8 +59,8 @@ impl Eq for StringList {}
 
 impl StringList {
     #[inline]
-    pub fn new(s: String, expandable: bool, string_tbl: TabledData<StringListWrapper>) -> Self {
-        let body = TabledRc::new(StringListWrapper(RefCell::new(s)), string_tbl);
+    pub fn new(s: String, expandable: bool) -> Self {
+        let body = Rc::new(StringListWrapper(RefCell::new(s)));
 
         StringList {
             cursor: 0,
@@ -76,12 +78,12 @@ impl StringList {
     pub fn set_expandable(&self) {
         self.expandable.set(true);
     }
-    
+
     #[inline]
     pub fn set_non_expandable(&self) {
         self.expandable.set(false);
     }
-    
+
     #[inline]
     pub fn push_char(&mut self, c: char) -> Self {
         if self.expandable.get() {
@@ -101,12 +103,12 @@ impl StringList {
         self.body.0.borrow_mut().extend(s.borrow()[s.cursor ..].chars());
         self.expandable.set(s.expandable.get());
     }
-    
+
     #[inline]
     pub fn cursor(&self) -> usize {
         self.cursor
-    }        
-    
+    }
+
     #[inline]
     pub fn head(&self) -> Option<char> {
         self.borrow()[self.cursor ..].chars().next()
@@ -127,7 +129,7 @@ impl StringList {
     pub fn is_empty(&self) -> bool {
         self.borrow().len() == self.cursor
     }
-    
+
     #[inline]
     pub fn borrow(&self) -> Ref<String> {
         self.body.0.borrow()