From 3967757ebd08837b230c308135f9244deb2f4807 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Peter=20Str=C3=B6mberg?= <pez@pezius.com>
Date: Wed, 6 Dec 2023 23:37:51 +0100
Subject: [PATCH] Port `clojure.core/reductions`

* Fixes #418
---
 resources/squint/core.edn |  1 +
 src/squint/core.js        | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/resources/squint/core.edn b/resources/squint/core.edn
index efd9df59..0896605f 100644
--- a/resources/squint/core.edn
+++ b/resources/squint/core.edn
@@ -142,6 +142,7 @@
   reduce_kv
   reduced
   reduced_QMARK_
+  reductions
   regexp_QMARK_
   remove
   remove_watch
diff --git a/src/squint/core.js b/src/squint/core.js
index 4a187aa4..b94284a3 100644
--- a/src/squint/core.js
+++ b/src/squint/core.js
@@ -582,6 +582,32 @@ export function reduce(f, arg1, arg2) {
   return val;
 }
 
+function _reductions(f, arg1, arg2) {
+  const [init, coll] = arg2 === undefined ? [undefined, arg1]: [arg1, arg2];
+  const s = seq(coll);
+  if (init === undefined) {
+    // (reductions f coll)
+    return new LazySeq(function () {
+      return s ? _reductions(f, first(s), rest(s)) : list(f());
+    });
+  } else {
+    // (reductions f val coll)
+    if (reduced_QMARK_(init)) {
+      return list(init.value);
+    }
+    return cons(init, new LazySeq(function () {
+      if (s) {
+        return _reductions(f, f(init, first(s)), rest(s));
+      }
+    }));
+  }
+}
+
+export function reductions(f, arg1, arg2) {
+  f = toFn(f);
+  return _reductions(f, arg1, arg2);
+}
+
 var tolr = false;
 export function warn_on_lazy_reusage_BANG_() {
   tolr = true;