2016 Update

Task/Metaprogramming/ALGOL-68/metaprogramming.alg

@@ -78,7 +78,7 @@ OP   WITH      = ( INSPECTTOREPLACE inspected, STRING replace with )REF STRING:
                   FI
             DO
                 result +:= replace with;
-                rest    := rest[ UPB to replace : ]
+                rest    := rest[ 1 + UPB to replace : ]
             OD
 
         ELIF option OF inspected = replace first

Task/Metaprogramming/Rust/metaprogramming.rust

@@ -0,0 +1,58 @@
+// dry.rs
+use std::ops::{Add, Mul, Sub};
+
+macro_rules! assert_equal_len {
+    // The `tt` (token tree) designator is used for
+    // operators and tokens.
+    ($a:ident, $b: ident, $func:ident, $op:tt) => (
+        assert!($a.len() == $b.len(),
+                "{:?}: dimension mismatch: {:?} {:?} {:?}",
+                stringify!($func),
+                ($a.len(),),
+                stringify!($op),
+                ($b.len(),));
+    )
+}
+
+macro_rules! op {
+    ($func:ident, $bound:ident, $op:tt, $method:ident) => (
+        fn $func<T: $bound<T, Output=T> + Copy>(xs: &mut Vec<T>, ys: &Vec<T>) {
+            assert_equal_len!(xs, ys, $func, $op);
+
+            for (x, y) in xs.iter_mut().zip(ys.iter()) {
+                *x = $bound::$method(*x, *y);
+                // *x = x.$method(*y);
+            }
+        }
+    )
+}
+
+// Implement `add_assign`, `mul_assign`, and `sub_assign` functions.
+op!(add_assign, Add, +=, add);
+op!(mul_assign, Mul, *=, mul);
+op!(sub_assign, Sub, -=, sub);
+
+mod test {
+    use std::iter;
+    macro_rules! test {
+        ($func: ident, $x:expr, $y:expr, $z:expr) => {
+            #[test]
+            fn $func() {
+                for size in 0usize..10 {
+                    let mut x: Vec<_> = iter::repeat($x).take(size).collect();
+                    let y: Vec<_> = iter::repeat($y).take(size).collect();
+                    let z: Vec<_> = iter::repeat($z).take(size).collect();
+
+                    super::$func(&mut x, &y);
+
+                    assert_eq!(x, z);
+                }
+            }
+        }
+    }
+
+    // Test `add_assign`, `mul_assign` and `sub_assign`
+    test!(add_assign, 1u32, 2u32, 3u32);
+    test!(mul_assign, 2u32, 3u32, 6u32);
+    test!(sub_assign, 3u32, 2u32, 1u32);
+}

Task/Metaprogramming/TXR/metaprogramming.txr

@@ -1,27 +1,26 @@
-@(do
-   (defmacro while ((condition : result) . body)
-     (let ((cblk (gensym "cnt-blk-"))
-           (bblk (gensym "brk-blk-")))
-       ^(macrolet ((break (value) ^(return-from ,',bblk ,value)))
-          (symacrolet ((break (return-from ,bblk))
-                       (continue (return-from ,cblk)))
-            (block ,bblk
-              (for () (,condition ,result) ()
-                (block ,cblk ,*body)))))))
+(defmacro whil ((condition : result) . body)
+  (let ((cblk (gensym "cnt-blk-"))
+        (bblk (gensym "brk-blk-")))
+    ^(macrolet ((break (value) ^(return-from ,',bblk ,value)))
+       (symacrolet ((break (return-from ,bblk))
+                    (continue (return-from ,cblk)))
+         (block ,bblk
+           (for () (,condition ,result) ()
+             (block ,cblk ,*body)))))))
 
-   (let ((i 0))
-     (while ((< i 100))
+(let ((i 0))
+  (whil ((< i 100))
+    (if (< (inc i) 20)
+      continue)
+    (if (> i 30)
+      break)
+    (prinl i)))
+
+(prinl
+  (sys:expand
+    '(whil ((< i 100))
        (if (< (inc i) 20)
          continue)
        (if (> i 30)
          break)
-       (prinl i)))
-
-   (prinl
-     (sys:expand
-       '(while ((< i 100))
-          (if (< (inc i) 20)
-            continue)
-          (if (> i 30)
-            break)
-          (prinl i)))))
+       (prinl i))))