From 3524a5df736ce3ca80e31afd13e88bfd55e75cb5 Mon Sep 17 00:00:00 2001
From: Jeremy Wall <jeremy@marzhillstudios.com>
Date: Wed, 6 Jun 2018 21:02:02 -0500
Subject: [PATCH] FEATURE: Comparison binary expressions now support
 non-compare expressions on both sides.

---
 src/build/compile_test.rs | 16 +++++++++-------
 src/parse/mod.rs          |  6 ++++--
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/build/compile_test.rs b/src/build/compile_test.rs
index c714d07..2947d54 100644
--- a/src/build/compile_test.rs
+++ b/src/build/compile_test.rs
@@ -1,5 +1,4 @@
 use super::Builder;
-use std;
 
 fn assert_build(input: &str) {
     let mut b = Builder::new("<Eval>");
@@ -13,8 +12,7 @@ fn assert_build(input: &str) {
 #[test]
 fn test_comparisons() {
     assert_build(
-        "
-    let one = 1;
+        "let one = 1;
     let two = 2;
     let foo = \"foo\";
     let bar = \"bar\";
@@ -45,8 +43,8 @@ fn test_comparisons() {
 
 #[test]
 fn test_deep_comparison() {
-    let input = "
-    let tpl1 = {
+    assert_build(
+        "let tpl1 = {
         foo = \"bar\",
         lst = [1, 2, 3],
         inner = {
@@ -65,8 +63,8 @@ fn test_deep_comparison() {
     assert \"tpl1 == copy\";
     assert \"tpl1 != extra\";
     assert \"tpl1 != less\";
-    ";
-    assert_build(input);
+    ",
+    );
 }
 
 #[test]
@@ -74,6 +72,10 @@ fn test_expression_comparisons() {
     assert_build("assert \"2 == 1+1\";");
     assert_build("assert \"(1+1) == 2\";");
     assert_build("assert \"(1+1) == (1+1)\";");
+    assert_build(
+        "let want = \"foo\";
+    assert \"select want, 1, { foo=2, } == 2\";",
+    );
 }
 
 #[test]
diff --git a/src/parse/mod.rs b/src/parse/mod.rs
index 005d6d5..099bf27 100644
--- a/src/parse/mod.rs
+++ b/src/parse/mod.rs
@@ -386,14 +386,16 @@ fn tuple_to_compare_expression(
     }))
 }
 
+// This macro is much simpler than the math binary expressions since they are the
+// bottom of the precendence tree and we can hard code the precedence in here.
 macro_rules! do_compare_expr {
     ($i:expr, $subrule:ident!( $($args:tt)* ), $typ:expr) => {
         map_res!($i,
             do_parse!(
                 pos: pos >>
-                left: alt!(simple_expression | grouped_expression | math_expression) >>
+                left: alt!(math_expression | non_op_expression) >>
                     $subrule!($($args)*) >>
-                    right: expression >>
+                    right: alt!(math_expression | non_op_expression) >>
                     (pos, $typ, left, right)
             ),
             tuple_to_compare_expression