add findall/3

src/prolog/heap.rs

@@ -0,0 +1,71 @@
+use prolog_parser::ast::*;
+
+use prolog::instructions::*;
+
+use std::ops::{Index, IndexMut};
+
+pub struct Heap {
+    heap: Vec<HeapCellValue>,
+    pub h: usize,
+}
+
+impl Heap {
+    pub fn with_capacity(cap: usize) -> Self {
+        Heap { heap: Vec::with_capacity(cap),
+               h: 0 }
+    }
+
+    pub fn push(&mut self, val: HeapCellValue) {
+        self.heap.push(val);
+        self.h += 1;
+    }
+
+    pub fn truncate(&mut self, h: usize) {
+        self.h = h;
+        self.heap.truncate(h);
+    }
+
+    pub fn len(&self) -> usize {
+        self.heap.len()
+    }
+
+    pub fn append(&mut self, vals: Vec<HeapCellValue>) {
+        let n = vals.len();
+
+        self.heap.extend(vals.into_iter());
+        self.h += n;
+    }
+
+    pub fn clear(&mut self) {
+        self.heap.clear();
+        self.h = 0;
+    }
+
+    pub fn to_list<Iter: Iterator<Item=Addr>>(&mut self, values: Iter) -> usize {
+        let head_addr = self.h;
+
+        for value in values {
+            let h = self.h;
+
+            self.push(HeapCellValue::Addr(Addr::Lis(h+1)));
+            self.push(HeapCellValue::Addr(value));
+        }
+
+        self.push(HeapCellValue::Addr(Addr::Con(Constant::EmptyList)));
+        head_addr
+    }
+}
+
+impl Index<usize> for Heap {
+    type Output = HeapCellValue;
+
+    fn index(&self, index: usize) -> &Self::Output {
+        &self.heap[index]
+    }
+}
+
+impl IndexMut<usize> for Heap {
+    fn index_mut(&mut self, index: usize) -> &mut Self::Output {
+        &mut self.heap[index]
+    }
+}