[gnome-calculator] equation: fix precedence of the root operator with regards to the unary minus

[Alberto Ruiz <aruiz src gnome org>]

commit 87f716dacc58a0cebf69142ab10a621ffdf1d907
Author: Alberto Ruiz <aruiz gnome org>
Date:   Sat Apr 16 00:22:06 2016 +0100

    equation: fix precedence of the root operator with regards to the unary minus

 lib/equation-parser.vala |   18 +++++++++---------
 tests/test-equation.vala |    1 +
 2 files changed, 10 insertions(+), 9 deletions(-)
---
diff --git a/lib/equation-parser.vala b/lib/equation-parser.vala
index 0c3ce6d..b00224d 100644
--- a/lib/equation-parser.vala
+++ b/lib/equation-parser.vala
@@ -26,15 +26,15 @@ private enum Precedence
     MOD             = 3,
     DIVIDE          = 3,
     NOT             = 4,
-    ROOT            = 5,
-    FUNCTION        = 6,
-    BOOLEAN         = 7,
-    PERCENTAGE      = 8,
-    /* UNARY_MINUS and POWER must have same precedence. */
-    UNARY_MINUS     = 9,
-    POWER           = 9,
-    FACTORIAL       = 10,
-    NUMBER_VARIABLE = 11,
+    FUNCTION        = 5,
+    BOOLEAN         = 6,
+    PERCENTAGE      = 7,
+    /* UNARY_MINUS, ROOT and POWER must have same precedence. */
+    UNARY_MINUS     = 8,
+    POWER           = 8,
+    ROOT            = 8,
+    FACTORIAL       = 9,
+    NUMBER_VARIABLE = 10,
     /* DEPTH should be always at the bottom. It stops node jumping off the current depth level. */
     DEPTH
 }
diff --git a/tests/test-equation.vala b/tests/test-equation.vala
index bde8e9e..4a4d561 100644
--- a/tests/test-equation.vala
+++ b/tests/test-equation.vala
@@ -689,6 +689,7 @@ private void test_precedence ()
     test ("- 4!", "−24", 0);
     test ("3! ^ 3", "216", 0);
     test ("3 ^ 3!", "729", 0);
+    test ("(−√3)^2", "3", 0);
 }
 
 private void test_custom_functions ()