iterator work

improve performance of split, chars, chars_ref
properly implement lily.iter.Iterator.fold
partially implement lily.iter.Iterator.collect
fix lily.iter.Skip logic
code cleanup
write proposed iterator spec

docs/spec/iter.md

@@ -1,2 +1,20 @@
 # iterators
-## spec to-be-defined
+## spec to-be-defined
+
+## proposed spec:
+
+```rust
+.{IterNext, Iterator} := @use("lily").iter
+
+Iterable := struct {
+    // ! required
+    // IterNext == struct { finished: bool, val: T }
+    next := fn(self: ^Self): IterNext(T)
+    into_iter := fn(self: Self): Iterator(Self)
+    // ! proposed
+    // addition of these two would allow for cheap implementation of `skip`, and `nth` in lily.iter.Iterator
+    peek := fn(self: ^Self): IterNext(T)
+    advance := fn(self: ^Self, n: uint): IterNext(T)
+    // ! proposed (waiting on compiler)
+    iter := fn(self: ^Self): Iterator(^Self)
+}

src/lily/collections/hashmap.hb

@@ -5,8 +5,12 @@ Item := fn($Key: type, $Value: type): type return packed struct {
 	value: Value,
 }
 
-Bucket := fn($Key: type, $Value: type, $Allocator: type): type return Vec(Item(Key, Value), Allocator)
-Buckets := fn($Key: type, $Value: type, $Allocator: type): type return Vec(Bucket(Key, Value, Allocator), Allocator)
+Bucket := fn($Key: type, $Value: type, $Allocator: type): type {
+	return Vec(Item(Key, Value), Allocator)
+}
+Buckets := fn($Key: type, $Value: type, $Allocator: type): type {
+	return Vec(Bucket(Key, Value, Allocator), Allocator)
+}
 
 HashMap := fn($Key: type, $Value: type, $Hasher: type, $Allocator: type): type return struct {
 	allocator: ^Allocator,

src/lily/collections/vec.hb

@@ -69,9 +69,6 @@ Vec := fn($T: type, $Allocator: type): type return struct {
 		i := 0
 		loop if self.get(i) == rhs return i else if i == self.slice.len return null else i += 1
 	}
-	$into_iter := fn(self: Self): iter.Iterator(iter.SliceIter(T)) {
-		return .(.(self.slice, 0))
-	}
 	$sort := fn(self: ^Self): void {
 		_ = quicksort(compare, self.slice, 0, self.slice.len - 1)
 	}

src/lily/iter.hb

@@ -46,9 +46,8 @@ Iterator := fn($T: type): type {
 		fold := fn(self: ^Self, $_fold: type, sum: Value): Value {
 			loop {
 				x := self.next()
-				y := self.next()
-				if y.finished return sum
-				sum += _fold(x.val, y.val)
+				if x.finished return sum
+				sum = _fold(sum, x.val)
 			}
 		}
 		nth := fn(self: ^Self, n: uint): ?Value {
@@ -59,6 +58,23 @@ Iterator := fn($T: type): type {
 				i += 1
 			}
 		}
+		collect := fn(self: ^Self, $A: type): ?A {
+			if Type(A).kind() != .Array {
+				@error("unsupported collect (for now)")
+			}
+			if @ChildOf(A) != Value {
+				@error("cannot collect of iterator of type", Value, "into type", A)
+			}
+			cont := Type(A).uninit()
+			i := 0
+			loop {
+				defer i += 1
+				x := self.next()
+				if i == @lenof(A) & x.finished return cont
+				if i == @lenof(A) | x.finished return null
+				cont[i] = x.val
+			}
+		}
 	}
 }
 
@@ -114,7 +130,7 @@ Skip := fn($T: type): type {
 			n := 0
 			loop {
 				x := self.iter.next()
-				if n == self.step return x
+				if n == self.step | x.finished return x
 				n += 1
 			}
 		}

src/lily/string.hb

@@ -68,21 +68,20 @@ split_once := fn(haystack: []u8, needle: @Any()): ?struct {left: []u8, right: []
 	}
 }
 
-split := fn(str: []u8, needle: @Any()): Iterator(struct {
+$split := fn(str: []u8, needle: @Any()): Iterator(struct {
 	str: []u8,
 	needle: @TypeOf(needle),
 	finished: bool = false,
 
 	next := fn(self: ^Self): IterNext([]u8) {
-		splits := split_once(self.str, self.needle)
 		if self.finished return .(true, Type([]u8).uninit())
+		splits := split_once(self.str, self.needle)
 		if splits != null {
 			self.str = splits.right
 			return .(false, splits.left)
-		} else {
-			self.finished = true
-			return .(false, self.str)
 		}
+		self.finished = true
+		return .(false, self.str)
 	}
 }) {
 	T := @TypeOf(needle)
@@ -92,11 +91,11 @@ split := fn(str: []u8, needle: @Any()): Iterator(struct {
 	return .(.{str, needle})
 }
 
-chars := fn(iter: []u8): Iterator(struct {
+$chars := fn(iter: []u8): Iterator(struct {
 	str: []u8,
 
 	$next := fn(self: ^Self): IterNext(u8) {
-		tmp := IterNext(u8).(self.str.len == 0, self.str[0])
+		tmp := IterNext(u8).(self.str.len == 0, *self.str.ptr)
 		self.str = self.str[1..]
 		return tmp
 	}
@@ -104,7 +103,7 @@ chars := fn(iter: []u8): Iterator(struct {
 	return .(.(iter))
 }
 
-chars_ref := fn(iter: []u8): Iterator(struct {
+$chars_ref := fn(iter: []u8): Iterator(struct {
 	str: []u8,
 
 	$next := fn(self: ^Self): IterNext(^u8) {

src/main.hb

@@ -1,15 +1,4 @@
-lily := @use("lily/lib.hb")
-
-Allocator := lily.alloc.SimpleAllocator
-Vec := lily.collections.Vec
-HashMap := lily.collections.HashMap
-Random := lily.rand.SimpleRandom
-Result := lily.result.Result
-Hasher := lily.hash.FoldHasher
-
-$ref_char_to_str := fn(char: ^u8): []u8 {
-	return char[0..1]
-}
+lily := @use("lily/lib.hb");
 
 Generator := struct {
 	n: uint = 0,
@@ -22,37 +11,28 @@ Generator := struct {
 	}
 }
 
-$add := fn(lhs: uint, rhs: uint): uint {
-	return lhs + rhs
+$add := fn(sum: uint, x: uint): uint {
+	return sum + x
 }
 
-chars_ref := lily.string.chars_ref
-
 main := fn(argc: uint, argv: []^void): uint {
-	a := Generator.{}.into_iter().take(50).fold(add, 0)
-	lily.print(a)
+	sum := Generator.{}.into_iter().take(50).fold(add, 0)
+	lily.print(sum)
 
-	b := chars_ref("Hello,_").chain(chars_ref("World!")).map(ref_char_to_str).for_each(lily.log.info)
-	c := chars_ref("Hello,_").intersperse(chars_ref("World!")).map(ref_char_to_str).for_each(lily.log.info)
+	// ! (libc) (compiler) bug: .collect(T) does not work.
+	if lily.Target.current() != .LibC {
+		str := lily.string.chars("Hello, ").intersperse(
+			lily.string.chars("World!"),
+		).collect([13]u8)
 
-	// allocator := Allocator.new()
-	// defer allocator.deinit()
-	// // ! HashMap only works on AbleOS target (due to compiler bugs)
-	// map := HashMap(uint, uint, Hasher, Allocator).new(&allocator)
-	// defer map.deinit()
-
-	// _ = map.insert(101, 20)
-	// _ = map.insert(202, 30)
-	// _ = map.insert(303, 40)
-
-	// // ! This iterator only works on AbleOS target (due to compiler bugs)
-	// map.items().enumerate().for_each(print)
+		if str != null {
+			lily.log.info(@as([13]u8, str)[..])
+		} else {
+			lily.panic("could not collect (array wrong size)")
+		}
+	} else {
+		lily.log.info("HWeolrllod,! ")
+	}
 
 	return 0
-}
-
-// $print := fn(thing: @Any()): void {
-// 	.{n, val: item} := thing
-// 	// ! printf ALSO only works on AbleOS target (due to compiler bugs)
-// 	lily.printf("nth: {}, key: {}, value: {}", .(n, item.key, item.value))
-// }
+}