scanl added, refactored mapHEADmain

1 files changed, 21 insertions, 0 deletions

diff --git a/src/fold.zig b/src/fold.zig
index ddaf0a9..f967cdf 100644
--- a/src/fold.zig
+++ b/src/fold.zig
@@ -50,3 +50,24 @@ pub fn foldr1(
 ) typeVerify(@TypeOf(func), .{ .@"fn" }).@"fn".return_type.? {
     return foldr(func, items[0], items);
 }
+
+pub fn scanlAlloc(
+    allocator: std.mem.Allocator,
+    comptime func: anytype,
+    base: (typeVerify(@TypeOf(func), .{.@"fn"}).@"fn".params[0].type.?),
+    items: ([]typeVerify(@TypeOf(func), .{.@"fn"}).@"fn".params[1].type.?)
+) ![]typeVerify(@TypeOf(func), .{.@"fn"}).@"fn".return_type.? {
+    var output = try allocator.alloc(typeVerify(@TypeOf(func), .{.@"fn"}).@"fn".return_type.?, items.len);
+    scanlBuffer(func, base, items, &output);
+    return output;
+}
+
+pub fn scanlBuffer(
+    comptime func: anytype,
+    base: (typeVerify(@TypeOf(func), .{.@"fn"}).@"fn".params[0].type.?),
+    items: ([]typeVerify(@TypeOf(func), .{.@"fn"}).@"fn".params[1].type.?),
+    buffer: (*[]typeVerify(@TypeOf(func), .{.@"fn"}).@"fn".return_type.?),
+) void {
+    for (buffer.*, 0..) |*out, i|
+        out.* = foldl(func, base, items[0..i+1]);
+}