From c5fa746e4ed2e05767306794e8d9480243562d7c Mon Sep 17 00:00:00 2001
From: Shannon Skipper <shannonskipper@gmail.com>
Date: Fri, 21 Jun 2024 22:31:18 +0000
Subject: [PATCH] Switch to `IndexMap` for consistent ordering

---
 Cargo.lock | 23 +++++++++++++++++++++++
 Cargo.toml |  1 +
 src/lib.rs |  8 ++++----
 3 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 356bb05..354cdf0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -289,6 +289,12 @@ version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3dca9240753cf90908d7e4aac30f630662b02aebaa1b58a3cadabdb23385b58b"
 
+[[package]]
+name = "equivalent"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
+
 [[package]]
 name = "float-cmp"
 version = "0.9.0"
@@ -308,6 +314,12 @@ dependencies = [
  "crunchy",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.14.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e5274423e17b7c9fc20b6e7e208532f9b19825d82dfd615708b70edd83df41f1"
+
 [[package]]
 name = "heck"
 version = "0.5.0"
@@ -320,6 +332,16 @@ version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d231dfb89cfffdbc30e7fc41579ed6066ad03abda9e567ccafae602b97ec5024"
 
+[[package]]
+name = "indexmap"
+version = "2.2.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "168fb715dda47215e360912c096649d23d58bf392ac62f73919e831745e40f26"
+dependencies = [
+ "equivalent",
+ "hashbrown",
+]
+
 [[package]]
 name = "is-terminal"
 version = "0.4.12"
@@ -831,6 +853,7 @@ dependencies = [
  "clap",
  "clap-stdin",
  "criterion",
+ "indexmap",
  "once_cell",
  "predicates",
  "serde",
diff --git a/Cargo.toml b/Cargo.toml
index 30ee2b9..341e558 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,6 +14,7 @@ version = "0.7.1"
 anyhow = "1.0.83"
 clap = { version = "4.5.4", features = ["derive"] }
 clap-stdin = "0.4.0"
+indexmap = "2.2.6"
 serde = { version = "1.0.203", features = ["derive"], optional = true } 
 serde_json = { version = "1.0.85", optional = true } 
 unescaper = "0.1.4"
diff --git a/src/lib.rs b/src/lib.rs
index 1a7b84a..af0471c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -33,9 +33,9 @@ use clap::ValueEnum;
 use core::cmp::Reverse;
 use core::fmt;
 use core::hash::{Hash, Hasher};
+use indexmap::IndexMap;
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
 use std::io::{BufRead, BufReader, Read};
 use unicode_segmentation::UnicodeSegmentation;
 
@@ -243,8 +243,8 @@ impl WordTally {
     }
 
     /// Creates a tally of normalized words from an input that implements `Read`.
-    fn tally_map<T: Read>(input: T, case: Case, chars: Chars) -> HashMap<String, u64> {
-        let mut tally = HashMap::new();
+    fn tally_map<T: Read>(input: T, case: Case, chars: Chars) -> IndexMap<String, u64> {
+        let mut tally = IndexMap::new();
         let lines = BufReader::new(input).lines();
 
         for line in lines.map_while(Result::ok) {
@@ -261,7 +261,7 @@ impl WordTally {
     }
 
     /// Removes words from the `tally_map` based on any word `Filters`.
-    fn filter(tally_map: &mut HashMap<String, u64>, filters: Filters, case: Case) {
+    fn filter(tally_map: &mut IndexMap<String, u64>, filters: Filters, case: Case) {
         // Remove any words that lack the minimum number of characters.
         if filters.count.min > 1 {
             tally_map.retain(|_, &mut count| count >= filters.count.min);