Currying, Combinators, and organization

1 files changed, 50 insertions, 0 deletions

diff --git a/src/combinators.zig b/src/combinators.zig
new file mode 100644
index 0000000..d78e40c
--- /dev/null
+++ b/src/combinators.zig
@@ -0,0 +1,50 @@
+const std = @import("std");
+const typeVerify = @import("util.zig").typeVerify;
+
+pub fn I(x: anytype) @TypeOf(x) {
+    return x;
+}
+
+pub fn K(x: anytype) fn(anytype) @TypeOf(x) {
+    return struct {
+        fn Kinner(y: anytype) @TypeOf(x) {
+            _=y;
+            return x;
+        }
+    }.Kinner;
+}
+
+fn SHelper(comptime x: anytype) type {
+    return struct {
+        pub fn call(comptime y: anytype) type {
+            return struct {
+                pub fn call(z: anytype) @TypeOf(x(z)(y(z))) {
+                    return x(z)(y(z));
+                }
+            };
+        }
+    };
+}
+
+pub fn S(comptime x: anytype) fn(anytype) fn(anytype) @TypeOf(blk: {
+    const dummy = struct {
+        fn d(a: anytype) @TypeOf(a) { return a; }
+    }.d;
+    break :blk x(dummy)(dummy);
+}) {
+    const Helper = SHelper(x);
+    return struct {
+        fn inner1(y: anytype) fn(anytype) @TypeOf(blk: {
+            const dummy = struct {
+                fn d(a: anytype) @TypeOf(a) { return a; }
+            }.d;
+            break :blk x(dummy)(y(dummy));
+        }) {
+            return struct {
+                fn inner2(z: anytype) @TypeOf(x(z)(y(z))) {
+                    return Helper.call(y).call(z);
+                }
+            }.inner2;
+        }
+    }.inner1;
+}