From 1392e0c477c7b27840f63821fb6cef393c7cb0f4 Mon Sep 17 00:00:00 2001
From: yyc <395976266@qq.com>
Date: Sun, 15 Nov 2020 17:49:43 +0800
Subject: [PATCH] perf: ListSt->traverse use iterate instead of recursive

---
 .../domain_layer/library/structure/ListSt.re  | 86 +++++--------------
 1 file changed, 21 insertions(+), 65 deletions(-)

diff --git a/src/construct/domain_layer/library/structure/ListSt.re b/src/construct/domain_layer/library/structure/ListSt.re
index afd73d726..cc720067a 100755
--- a/src/construct/domain_layer/library/structure/ListSt.re
+++ b/src/construct/domain_layer/library/structure/ListSt.re
@@ -1,27 +1,6 @@
 type t('index, 'value) = list('value);
 
-let rec traverseResultM = (list, f) => {
-  // define the monadic functions
-  let (>>=) = (x, f) => Result.bind(x, f);
-
-  let retn = Result.succeed;
-
-  // define a "cons" function
-  let cons = (head, tail) => [head, ...tail];
-  // loop through the list
-  switch (list) {
-  | [] =>
-    // if empty, lift [] to a Result
-    retn([])
-  | [head, ...tail] =>
-    // otherwise lift the head to a Result using f
-    // then lift the tail to a Result using traverse
-    // then cons the head and tail and return it
-    f(head) >>= (h => traverseResultM(tail, f) >>= (t => retn(cons(h, t))))
-  };
-};
-
-let traverseResultMi = (list, f) => {
+let traverseResultM = (list, f) => {
   // define the monadic functions
   let (>>=) = (x, f) => Result.bind(x, f);
 
@@ -30,40 +9,25 @@ let traverseResultMi = (list, f) => {
   // define a "cons" function
   let cons = (head, tail) => [head, ...tail];
 
-  let rec _traverse = (list, i, f) => {
-    // loop through the list
-    switch (list) {
-    | [] =>
-      // if empty, lift [] to a Result
-      retn([])
-    | [head, ...tail] =>
-      // otherwise lift the head to a Result using f
-      // then lift the tail to a Result using traverse
-      // then cons the head and tail and return it
-      f(i, head)
-      >>= (h => _traverse(tail, i->succ, f) >>= (t => retn(cons(h, t))))
-    };
-  };
-
-  _traverse(list, 0, f);
+  list
+  ->Belt.List.reduce(retn([]), (newListResult, value) => {
+      f(value)
+      >>= (h => newListResult >>= (newList => retn(cons(h, newList))))
+    })
+  ->Result.mapSuccess(newList => newList->Belt.List.reverse);
 };
 
-let rec traverseReduceResultM =
-        (list: list('a), param: 'b, f: ('b, 'a) => Result.t2('b))
-        : Result.t2('b) => {
+let traverseReduceResultM =
+    (list: list('a), param: 'b, f: ('b, 'a) => Result.t2('b))
+    : Result.t2('b) => {
   // define the monadic functions
   let (>>=) = (x, f) => Result.bind(x, f);
 
   let retn = Result.succeed;
 
-  // define a "cons" function
-  let cons = (head, tail) => [head, ...tail];
-  // loop through the list
-  switch (list) {
-  | [] => retn(param)
-  | [head, ...tail] =>
-    f(param, head) >>= (h => traverseReduceResultM(tail, h, f))
-  };
+  list->Belt.List.reduce(retn(param), (paramResult, value) => {
+    paramResult >>= (param => f(param, value))
+  });
 };
 
 let traverseReduceResultMi =
@@ -74,22 +38,14 @@ let traverseReduceResultMi =
 
   let retn = Result.succeed;
 
-  // define a "cons" function
-  let cons = (head, tail) => [head, ...tail];
-
-  let rec _traverse = (list, param, i, f) => {
-    // loop through the list
-    switch (list) {
-    | [] => retn(param)
-    | [head, ...tail] =>
-      // otherwise lift the head to a Result using f
-      // then lift the tail to a Result using traverse
-      // then cons the head and tail and return it
-      f(param, (i, head)) >>= (h => _traverse(tail, h, i->succ, f))
-    };
-  };
-
-  _traverse(list, param, 0, f);
+  list->Belt.List.reduce(retn((0, param)), (resultData, value) => {
+    resultData
+    >>= (
+      ((index, param)) =>
+        f(param, (index, value)) >>= (param => retn((index->succ, param)))
+    )
+  })
+  >>= (((_, param)) => retn(param));
 };
 
 let _id = value => value;