From 4587bee699efad97f53f809b71267fbdd671a6cb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alexander=20W=C3=BChr?= <alex@pnyhf.eu>
Date: Thu, 19 Sep 2024 17:29:47 +0200
Subject: [PATCH] refactor: straighten stack - part III

---
 src/fortheck/stack.gleam | 35 ++++++++++++-----------------------
 1 file changed, 12 insertions(+), 23 deletions(-)

diff --git a/src/fortheck/stack.gleam b/src/fortheck/stack.gleam
index 2610f1d..8c8eddd 100644
--- a/src/fortheck/stack.gleam
+++ b/src/fortheck/stack.gleam
@@ -1,6 +1,5 @@
-import gleam/bool
-import gleam/list
-import gleam/result
+import gleam/list.{reverse, try_fold}
+import gleam/result.{then, try}
 
 pub type Error {
   StackOverflow
@@ -12,7 +11,7 @@ pub opaque type Stack(a) {
 }
 
 pub fn new() -> Stack(a) {
-  Stack(131_072, 0, [])
+  Stack(capacity: 131_072, length: 0, data: [])
 }
 
 pub fn from_list(list: List(a)) -> Result(Stack(a), Error) {
@@ -20,23 +19,22 @@ pub fn from_list(list: List(a)) -> Result(Stack(a), Error) {
 }
 
 pub fn to_list(stack: Stack(a)) -> List(a) {
-  list.reverse(stack.data)
+  reverse(stack.data)
 }
 
 pub fn push(onto stack: Stack(a), this item: a) -> Result(Stack(a), Error) {
-  use <- bool.guard(
-    when: stack.length >= stack.capacity,
-    return: Error(StackOverflow),
-  )
-
-  Ok(Stack(..stack, length: stack.length + 1, data: [item, ..stack.data]))
+  case stack.length < stack.capacity {
+    True ->
+      Ok(Stack(..stack, length: stack.length + 1, data: [item, ..stack.data]))
+    False -> Error(StackOverflow)
+  }
 }
 
 pub fn push_items(
   onto stack: Stack(a),
   this items: List(a),
 ) -> Result(Stack(a), Error) {
-  list.try_fold(over: items, from: stack, with: push)
+  try_fold(over: items, from: stack, with: push)
 }
 
 pub fn pop(from stack: Stack(a)) -> Result(#(a, Stack(a)), Error) {
@@ -47,17 +45,8 @@ pub fn pop(from stack: Stack(a)) -> Result(#(a, Stack(a)), Error) {
 }
 
 pub fn pop_2(from stack: Stack(a)) -> Result(#(#(a, a), Stack(a)), Error) {
-  use #(b, stack) <- result.try(pop(from: stack))
-  use #(a, stack) <- result.try(pop(from: stack))
+  use #(b, stack) <- try(pop(from: stack))
+  use #(a, stack) <- then(pop(from: stack))
 
   Ok(#(#(a, b), stack))
 }
-
-pub fn try_pop_2(
-  from stack: Stack(a),
-  apply fun: fn(a, a, Stack(a)) -> Result(b, Error),
-) -> Result(b, Error) {
-  use #(#(a, b), stack) <- result.try(pop_2(from: stack))
-
-  fun(a, b, stack)
-}