From 00d4ef7ad8fa1974f0f95f98333774ec3362c9e2 Mon Sep 17 00:00:00 2001
From: Mark Thom <markjordanthom@gmail.com>
Date: Thu, 9 Aug 2018 18:23:47 -0600
Subject: [PATCH] print equations lexographically by variable name, re: #26

---
 src/prolog/machine/mod.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/prolog/machine/mod.rs b/src/prolog/machine/mod.rs
index 734baedc..d37f0055 100644
--- a/src/prolog/machine/mod.rs
+++ b/src/prolog/machine/mod.rs
@@ -481,7 +481,10 @@ impl Machine {
     pub fn heap_view<Outputter>(&self, var_dir: &HeapVarDict, mut output: Outputter) -> Outputter
        where Outputter: HCValueOutputter
     {
-        for (var, addr) in var_dir {
+        let mut sorted_vars: Vec<(&Rc<Var>, &Addr)> = var_dir.iter().collect();
+        sorted_vars.sort_by_key(|ref v| v.0);
+        
+        for (var, addr) in sorted_vars {
             let fmt = TermFormatter {};
             output = self.ms.print_var_eq(var.clone(), addr.clone(), var_dir, fmt, output);
         }
-- 
2.54.0