[PATCH 7/8] CodingGuidelines: on comparison

[Junio C Hamano <gitster@pobox.com>]

See http://thread.gmane.org/gmane.comp.version-control.git/3903/focus=4126

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/CodingGuidelines | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
index 21e4272..86fb9f6 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines
@@ -212,6 +212,32 @@ For C programs:
  - Double negation is often harder to understand than no negation
    at all.
 
+ - There are two schools of thought when it comes to comparison,
+   especially inside a loop. Some people prefer to have less stable
+   value on the left hand side and more stable value on the right hand
+   side, e.g. if you have a loop that counts variable i down to the
+   lower bound,
+
+	while (i > lower_bound) {
+		do something;
+		i--;
+	}
+
+   Other people prefer to have the textual order of values match the
+   actual order of values in their comparison, so that they can
+   mentally draw a number line from left to right and place these
+   values in order, i.e.
+
+	while (lower_bound < i) {
+		do something;
+		i--;
+	}
+
+   Both are valid, and we use both, even though we tend to see the
+   former the more preferable, the more "stable" the more stable side
+   becomes (comparison with a constant, "i > 0", is an extreme
+   example).  Just do not mix styles in the same part of the code.
+
  - Some clever tricks, like using the !! operator with arithmetic
    constructs, can be extremely confusing to others.  Avoid them,
    unless there is a compelling reason to use them.
-- 
2.0.0-rc1-355-gd6d6511