refactor to actual modules

src/prolog/machine/and_stack.rs

@@ -0,0 +1,91 @@
+use prolog::machine::machine_indices::*;
+
+use std::ops::{Index, IndexMut};
+use std::vec::Vec;
+
+#[derive(Clone)]
+pub struct Frame {
+    pub global_index: usize,
+    pub e: usize,
+    pub cp: LocalCodePtr,
+    pub special_form_cp: LocalCodePtr,
+    perms: Vec<Addr>
+}
+
+impl Frame {
+    fn new(global_index: usize, fr: usize, e: usize, cp: LocalCodePtr, n: usize) -> Self {
+        Frame {
+            global_index,
+            e: e,
+            cp: cp,
+            special_form_cp: LocalCodePtr::default(),
+            perms: (1 .. n+1).map(|i| Addr::StackCell(fr, i)).collect()
+        }
+    }
+
+    #[inline]
+    pub fn len(&self) -> usize {
+        self.perms.len()
+    }
+}
+
+pub struct AndStack(Vec<Frame>);
+
+impl AndStack {
+    pub fn new() -> Self {
+        AndStack(Vec::new())
+    }
+
+    pub fn push(&mut self, global_index: usize, e: usize, cp: LocalCodePtr, n: usize) {
+        let len = self.0.len();
+        self.0.push(Frame::new(global_index, len, e, cp, n));
+    }
+
+    pub fn len(&self) -> usize {
+        self.0.len()
+    }
+
+    pub fn clear(&mut self) {
+        self.0.clear()
+    }
+
+    pub fn resize(&mut self, fr: usize, n: usize) {
+        let len = self[fr].perms.len();
+
+        if len < n {
+            self[fr].perms.reserve(n - len);
+
+            for i in len .. n {
+                self[fr].perms.push(Addr::StackCell(fr, i));
+            }
+        }
+    }
+}
+
+impl Index<usize> for AndStack {
+    type Output = Frame;
+
+    fn index(&self, index: usize) -> &Self::Output {
+        self.0.index(index)
+    }
+}
+
+impl IndexMut<usize> for AndStack {
+    fn index_mut(&mut self, index: usize) -> &mut Self::Output {
+        self.0.index_mut(index)
+    }
+}
+
+impl Index<usize> for Frame {
+    type Output = Addr;
+
+    fn index(&self, index: usize) -> &Self::Output {
+        self.perms.index(index - 1)
+    }
+}
+
+impl IndexMut<usize> for Frame {
+    fn index_mut(&mut self, index: usize) -> &mut Self::Output {
+        self.perms.index_mut(index - 1)
+    }
+}