From 20cd0dd77a34c3a7feaef3338b5fddcb134d5cb1 Mon Sep 17 00:00:00 2001
From: Mark Thom <markjordanthom@gmail.com>
Date: Thu, 11 Feb 2021 15:35:14 -0700
Subject: [PATCH] use IndexMap over HashMap in prolog_parser

---
 crates/prolog_parser/Cargo.toml | 1 +
 crates/prolog_parser/src/ast.rs | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/crates/prolog_parser/Cargo.toml b/crates/prolog_parser/Cargo.toml
index e022c66c..b9dab9fd 100644
--- a/crates/prolog_parser/Cargo.toml
+++ b/crates/prolog_parser/Cargo.toml
@@ -8,6 +8,7 @@ description = " An operator precedence parser for the Rebis development version
 license = "BSD-3-Clause"
 
 [dependencies]
+indexmap = "1.0.2"
 lexical = "2.1.0"
 ordered-float = "0.5.0"
 rug = { optional = true, version = "1.4.0" }
diff --git a/crates/prolog_parser/src/ast.rs b/crates/prolog_parser/src/ast.rs
index fcde5b5a..3b9a9287 100644
--- a/crates/prolog_parser/src/ast.rs
+++ b/crates/prolog_parser/src/ast.rs
@@ -6,7 +6,6 @@ use crate::put_back_n::*;
 
 use std::cell::Cell;
 use std::cmp::Ordering;
-use std::collections::HashMap;
 use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::io::{Bytes, Error as IOError, Read};
@@ -14,6 +13,7 @@ use std::ops::Deref;
 use std::rc::Rc;
 use std::vec::Vec;
 
+use indexmap::IndexMap;
 use unicode_reader::CodePoints;
 
 pub type Atom = String;
@@ -278,7 +278,7 @@ impl OpDirValue {
 }
 
 // name and fixity -> operator type and precedence.
-pub type OpDir = HashMap<OpDirKey, OpDirValue>;
+pub type OpDir = IndexMap<OpDirKey, OpDirValue>;
 
 #[derive(Debug, Clone, Copy)]
 pub struct MachineFlags {
-- 
2.54.0