diff --git a/Makefile b/Makefile
new file mode 100644
index 00000000..5fc26cf8
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,10 @@
+
+default: main
+.PHONY: default
+
+include $(PUREC_DIR)/mk/target.mk
+
+SHELL := /bin/bash
+srcs := src test
+deps := bower_components/purescript-*/src
+$(eval $(call purs_mk_target,main,Test.Main,$(srcs),$(deps)))
diff --git a/src/Data/Array.c b/src/Data/Array.c
new file mode 100644
index 00000000..7d3f7f10
--- /dev/null
+++ b/src/Data/Array.c
@@ -0,0 +1,314 @@
+#include <purescript.h>
+
+//------------------------------------------------------------------------------
+// Array creation --------------------------------------------------------------
+//------------------------------------------------------------------------------
+
+PURS_FFI_FUNC_2(Data_Array_range, _start, _end, {
+	const purs_any_int_t start = purs_any_get_int(_start);
+	const purs_any_int_t end = purs_any_get_int(_end);
+	purs_any_int_t step = start > end ? -1 : 1;
+	purs_vec_t * result = (purs_vec_t *) purs_vec_new();
+	purs_any_int_t i = start;
+	while (i != end) {
+		purs_vec_push_mut(result, purs_any_int_new(i));
+		i += step;
+	}
+	purs_vec_push_mut(result, purs_any_int_new(i));
+	return purs_any_array_new(result);
+});
+
+PURS_FFI_FUNC_2(Data_Array_replicate, _count, value, {
+	const purs_any_int_t count = purs_any_get_int(_count);
+	purs_vec_t * result = (purs_vec_t *) purs_vec_new();
+	for (purs_any_int_t i = 0; i < count; i++) {
+		purs_vec_push_mut(result, value);
+	}
+	return purs_any_array_new(result);
+});
+
+PURS_FFI_FUNC_2(Data_Array_curryCons, head, tail, {
+	return purs_any_record_new(
+		purs_record_new_from_kvps(2, "head", head, "tail", tail));
+});
+
+PURS_FFI_FUNC_1(Data_Array_listToArray, list, {
+	purs_vec_t * result = (purs_vec_t *) purs_vec_new();
+	purs_any_t * xs = (purs_any_t *) list;
+	while (xs != NULL) {
+		const purs_record_t * record = purs_any_get_record(xs);
+		const purs_any_t * head = purs_record_find_by_key(record, "head")->value;
+		const purs_any_t * tail = purs_record_find_by_key(record, "tail")->value;
+		purs_vec_push_mut(result, head);
+		xs = (purs_any_t *) tail;
+	}
+	return purs_any_array_new(result);
+});
+
+PURS_FFI_FUNC_2(Data_Array_fromFoldableImpl, foldr, xs, {
+	return purs_any_app(Data_Array_listToArray$,
+				purs_any_app(
+					purs_any_app(
+						purs_any_app(foldr, Data_Array_curryCons$),
+						NULL
+					),
+					xs
+				)
+		 );
+});
+
+//------------------------------------------------------------------------------
+// Array size ------------------------------------------------------------------
+//------------------------------------------------------------------------------
+
+PURS_FFI_FUNC_1(Data_Array_length, _xs, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	return purs_any_int_new(xs->length);
+});
+
+//------------------------------------------------------------------------------
+// Extending arrays ------------------------------------------------------------
+//------------------------------------------------------------------------------
+
+PURS_FFI_FUNC_2(Data_Array_cons, e, l, {
+	return purs_any_array_new(purs_vec_insert(purs_any_get_array(l), 0, e));
+});
+
+PURS_FFI_FUNC_2(Data_Array_snoc, _l, e, {
+	const purs_vec_t * l = purs_any_get_array(_l);
+	return purs_any_array_new(purs_vec_insert(l, l->length, e));
+});
+
+//------------------------------------------------------------------------------
+// Non-indexed reads -----------------------------------------------------------
+//------------------------------------------------------------------------------
+
+PURS_FFI_FUNC_3(Data_Array_uncons$, empty, next, _xs, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	if (xs->length == 0) {
+		return purs_any_app(empty, NULL);
+	} else {
+		return purs_any_app(purs_any_app(next, xs->data[0]), purs_any_array_new(purs_vec_slice(xs, 1)));
+	}
+});
+
+//------------------------------------------------------------------------------
+// Indexed operations ----------------------------------------------------------
+//------------------------------------------------------------------------------
+
+PURS_FFI_FUNC_4(Data_Array_indexImpl, just, nothing, _xs, _i, {
+	const purs_any_int_t i = purs_any_get_int(_i);
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	if (i < 0 || i >= xs->length) {
+		return nothing;
+	} else {
+		return purs_any_app(just, xs->data[i]);
+	}
+});
+
+PURS_FFI_FUNC_4(Data_Array_findIndexImpl, just, nothing, f, _xs, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	for (purs_any_int_t i = 0; i < xs->length; i++) {
+		if (purs_any_app(f, xs->data[i]) == purs_any_true) {
+			return purs_any_app(just, purs_any_int_new(i));
+		}
+	}
+	return nothing;
+});
+
+PURS_FFI_FUNC_4(Data_Array_findLastIndexImpl, just, nothing, f, _xs, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	for (purs_any_int_t i = xs->length - 1; i >= 0; i--) {
+		if (purs_any_app(f, xs->data[i]) == purs_any_true) {
+			return purs_any_app(just, purs_any_int_new(i));
+		}
+	}
+	return nothing;
+});
+
+PURS_FFI_FUNC_5(Data_Array__insertAt, just, nothing, _i, a, _l, {
+	const purs_any_int_t i = purs_any_get_int(_i);
+	const purs_vec_t * l = purs_any_get_array(_l);
+	if (i < 0 || i > l->length) {
+		return nothing;
+	}
+	return purs_any_app(just, purs_any_array_new(purs_vec_insert(l, i, a)));
+});
+
+PURS_FFI_FUNC_4(Data_Array__deleteAt, just, nothing, _i, _l, {
+	const purs_any_int_t i = purs_any_get_int(_i);
+	const purs_vec_t * l = purs_any_get_array(_l);
+	if (i < 0 || i >= l->length) {
+		return nothing;
+	}
+	purs_vec_t * l1 = (purs_vec_t *) purs_vec_copy(l);
+	vec_splice(l1, i, 1);
+	return purs_any_app(just, purs_any_array_new(l1));
+});
+
+PURS_FFI_FUNC_5(Data_Array__updateAt, just, nothing, _i, a, _l, {
+	const purs_any_int_t i = purs_any_get_int(_i);
+	const purs_vec_t * l = purs_any_get_array(_l);
+	if (i < 0 || i >= l->length) {
+		return nothing;
+	}
+	purs_vec_t * l1 = (purs_vec_t *) purs_vec_copy(l);
+	l1->data[i] = a;
+	return purs_any_app(just, purs_any_array_new(l1));
+});
+
+//------------------------------------------------------------------------------
+// Transformations -------------------------------------------------------------
+//------------------------------------------------------------------------------
+
+PURS_FFI_FUNC_1(Data_Array_reverse, _l, {
+	const purs_vec_t * l = purs_any_get_array(_l);
+	purs_vec_t * result = (purs_vec_t *) purs_vec_new();
+	for (purs_any_int_t i = l -> length - 1; i >= 0; i--) {
+		purs_vec_push_mut(result, l->data[i]);
+	}
+	return purs_any_array_new(result);
+});
+
+PURS_FFI_FUNC_1(Data_Array_concat, xss, {
+	purs_any_int_t i;
+	purs_any_int_t j;
+	const purs_any_t * xs;
+	const purs_any_t * tmp;
+	purs_vec_t * result = (purs_vec_t *) purs_vec_new();
+	purs_vec_foreach(purs_any_get_array(xss), xs, i) {
+		purs_vec_foreach(purs_any_get_array(xs), tmp, j) {
+			purs_vec_push_mut(result, tmp);
+		}
+	}
+	return purs_any_array_new(result);
+});
+
+PURS_FFI_FUNC_2(Data_Array_filter, f, xs, {
+	const purs_any_t * tmp;
+	purs_any_int_t i;
+	purs_vec_t * result = (purs_vec_t *) purs_vec_new();
+	purs_vec_foreach(purs_any_get_array(xs), tmp, i) {
+		if (purs_any_app(f, tmp) == purs_any_true) {
+			purs_vec_push_mut(result, tmp);
+		}
+	}
+	return purs_any_array_new(result);
+});
+
+PURS_FFI_FUNC_2(Data_Array_partition, f, xs, {
+	purs_vec_t * yes = (purs_vec_t *) purs_vec_new();
+	purs_vec_t * no = (purs_vec_t *) purs_vec_new();
+	purs_any_int_t i;
+	const purs_any_t * tmp;
+	purs_vec_foreach(purs_any_get_array(xs), tmp, i) {
+		if (purs_any_app(f, tmp) == purs_any_true) {
+			purs_vec_push_mut(yes, tmp);
+		} else {
+			purs_vec_push_mut(no, tmp);
+		}
+	}
+	return purs_any_record_new(
+		purs_record_new_from_kvps(2,
+			"yes", purs_any_array_new(yes),
+			"no", purs_any_array_new(no)));
+});
+
+//------------------------------------------------------------------------------
+// Sorting ---------------------------------------------------------------------
+//------------------------------------------------------------------------------
+
+PURS_FFI_FUNC_2(Data_Array_sortImpl, f, _l, {
+	purs_vec_t * l = (purs_vec_t *) purs_vec_copy(purs_any_get_array(_l));
+	purs_any_int_t i;
+	purs_any_int_t j;
+	purs_any_int_t swapped;
+	const purs_any_t * tmp;
+
+	for (i = 0; i < l->length-1; i++) {
+		swapped = 0;
+		for (j = 0; j < l->length-i-1; j++) {
+		const purs_any_t * r = purs_any_app(purs_any_app(f, l->data[j]), l->data[j+1]);
+			if (purs_any_get_int(r) > 0) {
+				tmp = l->data[j];
+				l->data[j] = l->data[j+1];
+				l->data[j+1] = tmp;
+				swapped = 1;
+			}
+		}
+
+		// IF no two elements were swapped by inner loop, then break
+		if (swapped == 0) {
+			break;
+		}
+	}
+
+	return purs_any_array_new(l);
+});
+
+//------------------------------------------------------------------------------
+// Subarrays -------------------------------------------------------------------
+//------------------------------------------------------------------------------
+
+PURS_FFI_FUNC_3(Data_Array_slice, _s, _e, _l, {
+	const purs_any_int_t s = purs_any_get_int(_s);
+	const purs_any_int_t e = purs_any_get_int(_e);
+	const purs_vec_t * l = purs_any_get_array(_l);
+	purs_vec_t * out = (purs_vec_t *) purs_vec_new();
+	for (purs_any_int_t i = s; i < e; i ++) {
+		if (i >= 0 && i < l->length) {
+			purs_vec_push_mut(out, l->data[i]);
+		}
+	}
+	return purs_any_array_new(out);
+});
+
+PURS_FFI_FUNC_2(Data_Array_take, _n, _l, {
+	const purs_any_int_t n = purs_any_get_int(_n);
+	const purs_vec_t * l = purs_any_get_array(_l);
+	purs_vec_t * out = (purs_vec_t *) purs_vec_new();
+	for (purs_any_int_t i = 0; i < n; i ++) {
+		if (i >= 0 && i < l->length) {
+			purs_vec_push_mut(out, l->data[i]);
+		}
+	}
+	return purs_any_array_new(out);
+});
+
+PURS_FFI_FUNC_2(Data_Array_drop, _n, _l, {
+	const purs_any_int_t n = purs_any_get_int(_n);
+	const purs_vec_t * l = purs_any_get_array(_l);
+	if (n < 1) {
+		return _l;
+	}
+	purs_vec_t * out = (purs_vec_t *) purs_vec_new();
+	for (purs_any_int_t i = n; i < l->length; i++) {
+		purs_vec_push_mut(out, l->data[i]);
+	}
+	return purs_any_array_new(out);
+});
+
+//------------------------------------------------------------------------------
+// Zipping ---------------------------------------------------------------------
+//------------------------------------------------------------------------------
+
+PURS_FFI_FUNC_3(Data_Array_zipWith, f, _xs, _ys, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	const purs_vec_t * ys = purs_any_get_array(_ys);
+	purs_any_int_t l = xs->length < ys->length ? xs->length : ys->length;
+	purs_vec_t * out = (purs_vec_t *) purs_vec_new();
+	for (purs_any_int_t i = 0; i < l; i++) {
+		purs_vec_push_mut(out, purs_any_app(purs_any_app(f, xs->data[i]), ys->data[i]));
+	}
+	return purs_any_array_new(out);
+});
+
+//------------------------------------------------------------------------------
+// Partial ---------------------------------------------------------------------
+//------------------------------------------------------------------------------
+
+PURS_FFI_FUNC_2(Data_Array_unsafeIndexImpl, _xs, _n, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	const purs_any_int_t n = purs_any_get_int(_n);
+	return xs->data[n];
+});
diff --git a/src/Data/Array.h b/src/Data/Array.h
new file mode 100644
index 00000000..6a3a1162
--- /dev/null
+++ b/src/Data/Array.h
@@ -0,0 +1,30 @@
+#ifndef Data_Array_H
+#define Data_Array_H
+
+#include <purescript.h>
+
+PURS_FFI_EXPORT(Data_Array_range);
+PURS_FFI_EXPORT(Data_Array_replicate);
+PURS_FFI_EXPORT(Data_Array_fromFoldableImpl);
+PURS_FFI_EXPORT(Data_Array_length);
+PURS_FFI_EXPORT(Data_Array_cons);
+PURS_FFI_EXPORT(Data_Array_snoc);
+PURS_FFI_EXPORT(Data_Array_uncons$);
+PURS_FFI_EXPORT(Data_Array_indexImpl);
+PURS_FFI_EXPORT(Data_Array_findIndexImpl);
+PURS_FFI_EXPORT(Data_Array_findLastIndexImpl);
+PURS_FFI_EXPORT(Data_Array__insertAt);
+PURS_FFI_EXPORT(Data_Array__deleteAt);
+PURS_FFI_EXPORT(Data_Array__updateAt);
+PURS_FFI_EXPORT(Data_Array_reverse);
+PURS_FFI_EXPORT(Data_Array_concat);
+PURS_FFI_EXPORT(Data_Array_filter);
+PURS_FFI_EXPORT(Data_Array_partition);
+PURS_FFI_EXPORT(Data_Array_sortImpl);
+PURS_FFI_EXPORT(Data_Array_slice);
+PURS_FFI_EXPORT(Data_Array_take);
+PURS_FFI_EXPORT(Data_Array_drop);
+PURS_FFI_EXPORT(Data_Array_zipWith);
+PURS_FFI_EXPORT(Data_Array_unsafeIndexImpl);
+
+#endif // Data_Array_H
diff --git a/src/Data/Array.purs b/src/Data/Array.purs
index 9cdf06fe..d43d3a1d 100644
--- a/src/Data/Array.purs
+++ b/src/Data/Array.purs
@@ -866,8 +866,8 @@ groupBy op xs =
     iter <- STAI.iterator (xs !! _)
     STAI.iterate iter \x -> void do
       sub <- STA.empty
-      STAI.pushWhile (op x) iter sub
       _ <- STA.push x sub
+      STAI.pushWhile (op x) iter sub
       grp <- STA.unsafeFreeze sub
       STA.push ((unsafeCoerce :: Array ~> NonEmptyArray) grp) result
     STA.unsafeFreeze result
diff --git a/src/Data/Array/NonEmpty/Internal.c b/src/Data/Array/NonEmpty/Internal.c
new file mode 100644
index 00000000..471185eb
--- /dev/null
+++ b/src/Data/Array/NonEmpty/Internal.c
@@ -0,0 +1,102 @@
+#include <purescript.h>
+
+PURS_FFI_FUNC_2(Data_Array_NonEmpty_Internal_fold1Impl, f, _xs, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	const purs_any_t * acc = xs->data[0];
+	for (purs_any_int_t i = 1; i < xs->length; i++) {
+		acc = purs_any_app(purs_any_app(f, acc), xs->data[i]);
+	}
+	return acc;
+});
+
+PURS_FFI_FUNC_1(Cont, fn, {
+	return purs_any_record_new(
+				purs_record_new_from_kvps(2,
+					"type", purs_any_string_new("Cont"),
+					"fn", fn));
+});
+
+PURS_FFI_FUNC_1(finalCell, head, {
+	return purs_any_record_new(
+				purs_record_new_from_kvps(3,
+					"type", purs_any_string_new("ConsCell"),
+					"head", head,
+					"tail", NULL));
+});
+
+PURS_FFI_FUNC_2(consList, x, xs, {
+	return purs_any_record_new(
+				purs_record_new_from_kvps(3,
+					"type", purs_any_string_new("ConsCell"),
+					"head", x,
+					"tail", xs));
+});
+
+PURS_FFI_FUNC_1(listToArray, list, {
+	purs_vec_t * result = (purs_vec_t *) purs_vec_new();
+	purs_any_t * xs = (purs_any_t *) list;
+	while (xs != NULL) {
+		const purs_record_t * record = purs_any_get_record(xs);
+		const purs_any_t * head = purs_record_find_by_key(record, "head")->value;
+		const purs_any_t * tail = purs_record_find_by_key(record, "tail")->value;
+		purs_vec_push_mut(result, head);
+		xs = (purs_any_t *) tail;
+	}
+	return purs_any_array_new(result);
+});
+
+const purs_any_t * buildFrom(
+		const purs_any_t * apply,
+		const purs_any_t * map,
+		const purs_any_t * f,
+		const purs_any_t * x,
+		const purs_any_t * ys) {
+		return purs_any_app(
+					purs_any_app(
+						apply,
+						purs_any_app(
+							purs_any_app(map, consList$),
+							purs_any_app(f, x)
+						)
+					),
+					ys
+				 );
+}
+
+const purs_any_t * go(
+		const purs_any_t * apply,
+		const purs_any_t * map,
+		const purs_any_t * f,
+		const purs_any_t * acc,
+		const purs_any_int_t currentLen,
+		const purs_vec_t * xs) {
+	if (currentLen == 0) {
+		return acc;
+	} else {
+		const purs_any_t * last = xs->data[currentLen - 1];
+		const purs_any_t * fn = go(apply, map, f, buildFrom(apply, map, f, last, acc), currentLen - 1, xs);
+		return purs_any_app(Cont$, fn);
+	}
+}
+
+PURS_FFI_FUNC_4(Data_Array_NonEmpty_Internal_traverse1Impl, apply, map, f, _array, {
+	const purs_vec_t * array = purs_any_get_array(_array);
+	const purs_any_t * acc = purs_any_app(
+					purs_any_app(map, finalCell$),
+					purs_any_app(f, array->data[array->length - 1]));
+	const purs_any_t * result = go(apply, map, f, acc, array->length - 1, array);
+	while (1) {
+		if (result -> tag != PURS_ANY_TAG_RECORD) {
+			break;
+		}
+		const purs_record_t * record = purs_any_get_record(result);
+		const purs_any_t * tp = purs_record_find_by_key(record, "type")->value;
+		if (purs_any_eq_string(tp, "Cont")) {
+			result = purs_record_find_by_key(record, "fn")->value;
+		} else {
+			break;
+		}
+	}
+
+	return purs_any_app(purs_any_app(map, listToArray$), result);
+});
diff --git a/src/Data/Array/NonEmpty/Internal.h b/src/Data/Array/NonEmpty/Internal.h
new file mode 100644
index 00000000..fcdef01d
--- /dev/null
+++ b/src/Data/Array/NonEmpty/Internal.h
@@ -0,0 +1,9 @@
+#ifndef Data_Array_NonEmpty_Internal_H
+#define Data_Array_NonEmpty_Internal_H
+
+#include <purescript.h>
+
+PURS_FFI_EXPORT(Data_Array_NonEmpty_Internal_fold1Impl);
+PURS_FFI_EXPORT(Data_Array_NonEmpty_Internal_traverse1Impl);
+
+#endif // Data_Array_NonEmpty_Internal_H
diff --git a/src/Data/Array/ST.c b/src/Data/Array/ST.c
new file mode 100644
index 00000000..1a5a7125
--- /dev/null
+++ b/src/Data/Array/ST.c
@@ -0,0 +1,115 @@
+#include <purescript.h>
+
+PURS_FFI_FUNC_1(Data_Array_ST_empty, _, {
+	return purs_any_array_new(purs_vec_new());
+});
+
+PURS_FFI_FUNC_5(Data_Array_ST_peekImpl, just, nothing, _i, _xs, _, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	const purs_any_int_t i = purs_any_get_int(_i);
+	if (i >= 0 && i< xs->length) {
+		return purs_any_app(just, xs->data[i]);
+	} else {
+		return nothing;
+	}
+});
+
+PURS_FFI_FUNC_4(Data_Array_ST_poke, _i, a, _xs, _, {
+	purs_vec_t * xs = (purs_vec_t *) purs_any_get_array(_xs);
+	const purs_any_int_t i = purs_any_get_int(_i);
+	if (i >= 0 && i < xs->length) {
+		xs->data[i] = a;
+		return purs_any_true;
+		} else {
+			return purs_any_false;
+		}
+});
+
+PURS_FFI_FUNC_3(Data_Array_ST_pushAll, _as, _xs, _, {
+	purs_vec_t * xs = (purs_vec_t *) purs_any_get_array(_xs);
+	const purs_vec_t * as = purs_any_get_array(_as);
+	const purs_any_t * tmp;
+	purs_any_int_t i;
+	purs_vec_foreach(as, tmp, i) {
+		purs_vec_push_mut(xs, tmp);
+	}
+	return purs_any_int_new(xs -> length);
+});
+
+PURS_FFI_FUNC_5(Data_Array_ST_splice, _i, _howMany, _bs, _xs, _, {
+	const purs_any_int_t i = purs_any_get_int(_i);
+	const purs_any_int_t howMany = purs_any_get_int(_howMany);
+	const purs_vec_t * bs = purs_any_get_array(_bs);
+	purs_vec_t * xs = (purs_vec_t *) purs_any_get_array(_xs);
+	purs_vec_t * out = (purs_vec_t *) purs_vec_new();
+	purs_vec_t * head = (purs_vec_t *) purs_vec_new();
+	purs_vec_t * tail = (purs_vec_t *) purs_vec_new();
+	const purs_any_t * tmp;
+	purs_any_int_t j;
+	purs_vec_foreach(xs, tmp, j) {
+		if (j >= i) {
+			if (out->length < howMany) {
+				purs_vec_push_mut(out, tmp);
+			} else {
+				purs_vec_push_mut(tail, tmp);
+			}
+		} else {
+			purs_vec_push_mut(head, tmp);
+		}
+	}
+	purs_vec_reserve(xs, head->length + tail->length + bs->length);
+	purs_vec_foreach(bs, tmp, j) {
+		xs->data[head->length + j] = tmp;
+	}
+	purs_vec_foreach(tail, tmp, j) {
+		xs->data[head->length + bs->length + j] = tmp;
+	}
+	xs->length = head->length + tail->length + bs->length;
+	return purs_any_array_new(out);
+});
+
+PURS_FFI_FUNC_2(Data_Array_ST_copyImpl, _xs, _, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	return purs_any_array_new(purs_vec_copy(xs));
+});
+
+PURS_FFI_FUNC_3(Data_Array_ST_sortByImpl, comp, _xs, _, {
+	purs_vec_t * xs = (purs_vec_t *) purs_any_get_array(_xs);
+	purs_any_int_t i;
+	purs_any_int_t j;
+	purs_any_int_t swapped;
+	const purs_any_t * tmp;
+
+	for (i = 0; i < xs->length-1; i++) {
+		swapped = 0;
+		for (j = 0; j < xs->length-i-1; j++) {
+		const purs_any_t * r = purs_any_app(purs_any_app(comp, xs->data[j]), xs->data[j+1]);
+			if (purs_any_get_int(r) > 0) {
+				tmp = xs->data[j];
+				xs->data[j] = xs->data[j+1];
+				xs->data[j+1] = tmp;
+				swapped = 1;
+			}
+		}
+
+		// IF no two elements were swapped by inner loop, then break
+		if (swapped == 0) {
+			break;
+		}
+	}
+
+	return purs_any_array_new(xs);
+});
+
+PURS_FFI_FUNC_2(Data_Array_ST_toAssocArray, _xs, _, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	purs_any_int_t i;
+	const purs_any_t * tmp;
+	purs_vec_t * out = (purs_vec_t *) purs_vec_new();
+	purs_vec_foreach(xs, tmp, i) {
+	purs_vec_push_mut(out, purs_any_record_new(
+				purs_record_new_from_kvps(2, "value", tmp, "index", purs_any_int_new(i))
+				));
+	}
+	return purs_any_array_new(out);
+});
diff --git a/src/Data/Array/ST.h b/src/Data/Array/ST.h
new file mode 100644
index 00000000..e01625c7
--- /dev/null
+++ b/src/Data/Array/ST.h
@@ -0,0 +1,15 @@
+#ifndef Data_Array_ST_H
+#define Data_Array_ST_H
+
+#include <purescript.h>
+
+PURS_FFI_EXPORT(Data_Array_ST_empty);
+PURS_FFI_EXPORT(Data_Array_ST_peekImpl);
+PURS_FFI_EXPORT(Data_Array_ST_poke);
+PURS_FFI_EXPORT(Data_Array_ST_pushAll);
+PURS_FFI_EXPORT(Data_Array_ST_splice);
+PURS_FFI_EXPORT(Data_Array_ST_copyImpl);
+PURS_FFI_EXPORT(Data_Array_ST_sortByImpl);
+PURS_FFI_EXPORT(Data_Array_ST_toAssocArray);
+
+#endif // Data_Array_ST_H
diff --git a/src/Data/Array/ST/Partial.c b/src/Data/Array/ST/Partial.c
new file mode 100644
index 00000000..011321b2
--- /dev/null
+++ b/src/Data/Array/ST/Partial.c
@@ -0,0 +1,14 @@
+#include <purescript.h>
+
+PURS_FFI_FUNC_3(Data_Array_ST_Partial_peekImpl, _i, _xs, _, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	const purs_any_int_t i = purs_any_get_int(_i);
+	return xs->data[i];
+});
+
+PURS_FFI_FUNC_4(Data_Array_ST_Partial_pokeImpl, _i, a, _xs, _, {
+	const purs_vec_t * xs = purs_any_get_array(_xs);
+	const purs_any_int_t i = purs_any_get_int(_i);
+	xs->data[i] = a;
+	return NULL;
+});
diff --git a/src/Data/Array/ST/Partial.h b/src/Data/Array/ST/Partial.h
new file mode 100644
index 00000000..c9fd9032
--- /dev/null
+++ b/src/Data/Array/ST/Partial.h
@@ -0,0 +1,9 @@
+#ifndef Data_Array_ST_Partial_H
+#define Data_Array_ST_Partial_H
+
+#include <purescript.h>
+
+PURS_FFI_EXPORT(Data_Array_ST_Partial_peekImpl);
+PURS_FFI_EXPORT(Data_Array_ST_Partial_pokeImpl);
+
+#endif // Data_Array_ST_Partial_H
diff --git a/test/Test/Data/Array.purs b/test/Test/Data/Array.purs
index 53556ac6..d1c59f6a 100644
--- a/test/Test/Data/Array.purs
+++ b/test/Test/Data/Array.purs
@@ -306,6 +306,9 @@ testArray = do
   log "groupBy should group consecutive equal elements into arrays based on an equivalence relation"
   assert $ A.groupBy (\x y -> odd x && odd y) [1, 1, 2, 2, 3, 3] == [nea [1, 1], NEA.singleton 2, NEA.singleton 2, nea [3, 3]]
 
+  log "groupBy should be stable"
+  assert $ A.groupBy (\_ _ -> true) [1, 2, 3] == [nea [1, 2, 3]]
+
   log "nub should remove duplicate elements from the list, keeping the first occurence"
   assert $ A.nub [1, 2, 2, 3, 4, 1] == [1, 2, 3, 4]