use mem pool for cons

2 files changed, 11 insertions, 4 deletions

diff --git a/src/libzisp/gc.zig b/src/libzisp/gc.zig
index 6704102..92b4387 100644
--- a/src/libzisp/gc.zig
+++ b/src/libzisp/gc.zig
@@ -2,11 +2,21 @@ const std = @import("std");
 
 const value = @import("value.zig");
 
+const Value = value.Value;
 const Hval = value.Hval;
 
 var _gpa: std.heap.GeneralPurposeAllocator(.{}) = .init;
 const gpa = _gpa.allocator();
 
+var cpool = std.heap.MemoryPool([2]Value).init(gpa);
+
+pub fn cons(v1: Value, v2: Value) *[2]Value {
+    const mem = cpool.create() catch @panic("OOM");
+    mem[0] = v1;
+    mem[1] = v2;
+    return mem;
+}
+
 pub fn alloc(count: usize) []Hval {
     return gpa.alloc(Hval, count) catch @panic("OOM");
 }
diff --git a/src/libzisp/value/pair.zig b/src/libzisp/value/pair.zig
index 1c34096..87e18e7 100644
--- a/src/libzisp/value/pair.zig
+++ b/src/libzisp/value/pair.zig
@@ -26,10 +26,7 @@ pub fn pred(v: Value) Value {
 }
 
 pub fn cons(v1: Value, v2: Value) Value {
-    const mem = gc.alloc(2);
-    mem[0] = .{ .value = v1 };
-    mem[1] = .{ .value = v2 };
-    return ptr.pack(mem.ptr, .pair);
+    return ptr.pack(@ptrCast(gc.cons(v1, v2)), .pair);
 }
 
 fn getMem(v: Value) *[2]Value {